Host immune response in immunodeficient mice against infection with Cryptosporidium parvum

Immunantwort von immundefizienten Mäusen gegenüber Infektionen mit Cryptosporidium parvum. Cryptosporidium parvum ist ein intrazellulärer, protozoischer Krankheitserreger, der im immunkompromittierten Wirt zu lebensbedrohender Enteritis führen kann. CD4+ T-Zellen und Interferon (IFN)-γ spielen wesentliche Rollen bei der Wirtsimmunantwort gegen die Infektion. Dennoch sind die Effektormechanismen, die zur Resistenz führen nur wenig verstanden. In dieser Studie wurde die Immunantwort von IFN-γ- und Interleukin (IL)-12-Defektmäusen parallel zu Wildtypmäusen analysiert. Die Ergebnisse identifizierten IFN-γ als Schlüsselzytokin bei der natürlichen und erworbenen Immunität während der Erst- und Folgeinfektion mit C. parvum. Tumornekrosefaktor (TNF)-α ist möglicherweise ein Induktor der frühen IFN-γ-Antwort in IL-12 Knockout-Mäusen. Weiterhin tragen offenbar sowohl Th1- als auch Th2-Zytokine zur Überwindung der Primärinfektion bei, die ersten mehr als die letztgenannten. Zytokingene waren am Ort der Infektion (Ileum) dramatisch verändert, nicht aber in den lokalen Lymphknoten und der Milz. Nach Folgeinfektion ergab sich in Abwesenheit von IFN-γ eine signifikante Erhöhung der Th2-Zytokine IL-5 and IL-13. Die Ergebnisse zeigten weiterhin, dass das Th1-Zytokin IL-18 zur Resistenz gegenüber C. parvum beiträgt, möglicherweise durch verschiedene Immunfunktionen, wie der Regulation von Serum-IFN-γ während der Infektion und/oder der Erhaltung der Homeostase der Th1/Th2-Zytokine durch Regulation der Th2-Zytokine. Weiterhin zeigten diese Untersuchungen den Transfer von Resistenz gegenüber C. parvum von infizierten auf naïve Mäuse mittels stimulierter intraepithelialer Lymphozyten und CD4+ T-Zellen. Diese Ergebnisse weisen auf die Gegenwart von C. parvum-spezifischen CD4+ T-Zellen in anderen lymphatischen Geweben neben der Darmmukosa hin. Eine Stimulation der Spendertiere durch Infektion war notwendig für eine übertragbare schützende Immunität. Dennoch konnte die übertragene Immunität nicht die Infektion der Empfängertiere vollständig verhindern; eine Verdopplung der Spenderzellen führte zu keinem besseren Ergebnis. Weiterhin ergab der Transfer von CD4+ und CD8+ T-Zellen (Pan-T-Zellen) keinen erhöhten Schutz der naiven Empfängertiere als der alleinige Transfer von CD4+ T-Zellen. Dies weist auf die fehlende Bedeutung der CD8+ T-Zellen beim Schutz vor C. parvum-Infektion hin.

Immune response in human melanoma after transfer of an allogeneic class I major histocompatibility complex gene with DNA–liposome complexes

Analysis of the antitumor immune response after gene transfer of a foreign major histocompatibility complex class I protein, HLA-B7, was performed. Ten HLA-B7-negative patients with stage IV melanoma were treated in an effort to stimulate local tumor immunity. Plasmid DNA was detected within treated tumor nodules, and RNA encoding recombinant HLA-B7 or HLA-B7 protein was demonstrated in 9 of 10 patients. T cell migration into treated lesions was observed and tumor-infiltrating lymphocyte reactivity was enhanced in six of seven and two of two patients analyzed, respectively. In contrast, the frequency of cytotoxic T lymphocyte against autologous tumor in circulating peripheral blood lymphocytes was not altered significantly, suggesting that peripheral blood lymphocyte reactivity is not indicative of local tumor responsiveness. Local inhibition of tumor growth was detected after gene transfer in two patients, one of whom showed a partial remission. This patient subsequently received treatment with tumor-infiltrating lymphocytes derived from gene-modified tumor, with a complete regression of residual disease. Thus, gene transfer with DNA–liposome complexes encoding an allogeneic major histocompatibility complex protein stimulated local antitumor immune responses that facilitated the generation of effector cells for immunotherapy of cancer.

In vivo- und in vitro-Untersuchungen zur Immunantwort und Parasitenentwicklung bei Infektionen mit dem Darmparasiten Cryptosporidium parvum

Cryptosporidium parvum ist ein intrazellulärer protozoischer Darmparasit (Apikomplexa), der weltweit zu den bedeutendsten Erregern von Diarrhöen beim Menschen und einer Reihe von Nutztieren zählt. Vor allem immunkompromittierte Personen wie zum Beispiel AIDS-Patienten erleiden schwere, chronische bis lebensbedrohende Erkrankungen. Da nach wie vor keine effektive Therapie gegen eine Kryptosporidiose in Form eines spezifisch wirkenden Chemotherapeutikums oder einer Vakzine existiert, ist es notwendig, die Immunantwort des Wirtes gegen den Parasiten und dessen Bindung, Invasion und die intrazelluläre Entwicklung in den Epithelzellen eingehend zu studieren, um neue Ansatzpunkte zu entwickeln. Wohingegen Menschen zeitlebens suszeptibel für eine Infektion mit C. parvum sind, entwickeln Mäuse eine natürliche Resistenz und können als adulte Tiere nicht mehr infiziert werden. Daher sind Mausmodelle der Kryptosporidiose auf neonatale oder immunsupprimierte und immundefiziente adulte Mäuse beschränkt. Bei der Überwindung einer C. parvum-Infektion sind Effektoren der natürlichen und adaptiven Immunität beteiligt. Die zentrale Rolle spielen CD4+-T-Zellen, sowie Interferon-gamma und Interleukin-12. Im Rahmen dieser Arbeit wurden Infektionen in IFN-gamma (GKO)- und IL-12 p40 (IL12KO)-Knockout-Mäusen (C57BL/6) etabliert, für die bereits gezeigt wurde, dass sie eine Suszeptibilität gegenüber einer Erstinfektion besitzen. Erstmals wurden die beiden Infektionsmodelle parallel unter denselben Bedingungen analysiert, um Rückschlüsse auf die Funktion und die Bedeutung der beiden Th1-Zytokine IFN-gamma und IL-12 bei der Auseinandersetzung mit dem Parasiten und der Überwindung einer Infektion ziehen zu können. Es wurden deutliche Unterschiede im Infektionsverlauf, bei der Höhe und Dauer der Parasitenausscheidung und der induzierten systemischen und mukosalen Antikörperantwort beobachtet. Zum ersten Mal konnte gezeigt werden, dass neben IL12KO auch GKO in der Lage sind, eine erste Infektion zu überwinden und eine Resistenz gegenüber einer erneuten Konfrontation mit dem Parasiten zu entwickeln. Alle Ergebnisse deuten darauf hin, dass die Etablierung einer protektiven Immunität gegen eine Kryptosporidiose generell unabhängig von der Anwesenheit der Zytokine IFN-gamma und IL-12 ist, der Verlust von IFN-gamma jedoch schwerer wiegt. Bei GKO-Mäusen persistierte der Parasit in Form einer niedriggradigen chronischen Infektion. Die beiden Infektionsmodelle stellten sich als ideales System für die Etablierung einer effektiven Immunisierungsstrategie heraus. Intranasale Immunisierungen, welche neben einer systemischen auch eine mukosale Immunantwort induzieren können, schienen einen richtigen Ansatz darzustellen. Intraperitoneale und subkutane Immunisierungen führten zwar zur Ausbildung einer starken spezifischen IgG-Antwort im Serum, diese war jedoch nicht in der Lage, einen Schutz vor einer Infektion zu vermitteln. Neben den in vivo Untersuchungen wurde des Weiteren auch die intrazelluläre Entwicklung von C. parvum in einem in vitro Kultursystem verfolgt. Zum ersten Mal wurde die Genexpression von vier Oberflächenproteinen der invasiven Zoitenstadien und eines Oozystenwandproteins parallel durch RT-PCR analysiert. Es konnte gezeigt werden, dass alle untersuchten Gene während der intrazellulären Entwicklung differentiell exprimiert werden, was eine unterschiedliche Funktion der Proteine während des Entwicklungszyklus nahe legt. Das Expressionsmuster der verschiedenen Gene charakterisiert bestimmte Abschnitte innerhalb des Entwicklungszyklus. Dabei wurden Marker für die Invasion (CP17) sowie für die asexuelle (GP900) und sexuelle Replikation (COWP) identifiziert.

Broiler breeder feeding programs and trace minerals on maternal antibody transfer and broiler humoral immune response

Breeder feed restriction may negatively affect broiler progeny immunity. Sources of trace minerals (TM) with higher bioavailability in breeder diets have been reported to enhance humoral and cellular immunity in broiler progeny. An experiment was conducted to examine the effects of breeder feeding programs and TM dietary sources on maternal antibody transfer and humoral immune response of progeny to a live vaccine against Newcastle disease virus (NDV). Cobb 500 breeders were fed according to 2 feed allocation programs, sigmoid late fast and sigmoid late slow, from 14 to 29 wk of age. From 56 to 62 wk of age, breeders were fed with either inorganic TM or an organic source (OTM) to replace 30% of Cu, Zn, and Mn. Progeny broilers were vaccinated intraocularly with La Sota NDV vaccine at 7 d of age. Blood samples were collected at hatching, 4, and 14 d postvaccination. Serum antibody levels against NDV were assessed by ELISA and cytokine expression by real time PCR. At hatching, late slow breeder progeny fed diets with 30% OTM had higher antibody titers as compared with progeny of breeders fed 100% inorganic TM. Similar results were observed 2 wk postvaccination. Breeder feeding programs and TM sources affected the expression level of IL-4 in NDV vaccinated broiler progeny. It was concluded that breeder feeding programs influenced humoral immune response to NDV vaccine in the broiler progeny, and 30% OTM may increase these responses. © 2013 Poultry Science Association, Inc.

Immune response in pemphigus and beyond: progresses and emerging concepts

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are two severe autoimmune bullous diseases of the mucosae and/or skin associated with autoantibodies directed against desmoglein (Dsg) 3 and/or Dsg1. These two desmosomal cadherins, typifying stratified epithelia, are components of cell adhesion complexes called desmosomes and represent extra-desmosomal adhesion receptors. We herein review the advances in our understanding of the immune response underlying pemphigus, including human leucocyte antigen (HLA) class II-associated genetic susceptibility, characteristics of pathogenic anti-Dsg antibodies, antigenic mapping studies as well as findings about Dsg-specific B and T cells. The pathogenicity of anti-Dsg autoantibodies has been convincingly demonstrated. Disease activity and clinical phenotype correlate with anti-Dsg antibody titers and profile while passive transfer of anti-Dsg IgG from pemphigus patients' results in pemphigus-like lesions in neonatal and adult mice. Finally, adoptive transfer of splenocytes from Dsg3-knockout mice immunized with murine Dsg3 into immunodeficient mice phenotypically recapitulates PV. Although the exact pathogenic mechanisms leading to blister formation have not been fully elucidated, intracellular signaling following antibody binding has been found to be necessary for inducing cell-cell dissociation, at least for PV. These new insights not only highlight the key role of Dsgs in maintenance of tissue homeostasis but are expected to progressively change pemphigus management, paving the way for novel targeted immunologic and pharmacologic therapies.

Comparative T cell receptor repertoire selection by antigen after adoptive transfer: A glimpse at an antigen-specific preimmune repertoire

The low frequency of precursor cells specific for any particular antigen (Ag) makes it difficult to characterize preimmune T cell receptor (TCR) repertoires and to understand repertoire selection during an immune response. We have undertaken a combined adoptive transfer single-cell PCR approach to probe the Ag-specific preimmune repertoires of individual mice. Our strategy was to inject paired irradiated recipient mice with normal spleen cells prepared from individual donors and to compare the TCR repertoires subsequently selected during a CD8 response to a defined model Ag. We found that although some TCRs were shared, the TCR repertoires selected by mice receiving splenocytes from the same donor were not identical in terms of the TCRs selected and their relative frequencies. Our results together with computer simulations imply that individual mice express distinct Ag-specific preimmune TCR repertoires composed of expanded clones and that selection by Ag is a random process.

Re-examination of the rainbow trout (Oncorhynchus mykiss) immune response to flagellin : Yersinia ruckeri flagellin is a potent activator of acute phase proteins, anti-microbial peptides and pro-inflammatory cytokines in vitro

Copyright © 2015. Published by Elsevier Ltd. E.W. was supported by a PhD studentship from the Ministry of Science and Technology of Thailand and Mahasarakham University. T.W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), that is funded by the Scottish Funding Council (grant reference HR09011). This research was also funded by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (grant agreement No. 311993 TARGETFISH).

Studies on the protective immune response to Plasmodium chabaudi in mice

Inbred strains of C5731 and NIH nice infected with the A/S strain of Plasmodium chaubaudi usually developed high parasitaemias but infections were rarely fatal in immunocompetent mice and in most mice the parasites could be eradicated within 53 days or less. The immune response of C57B1 and NTH mice to infection with the A/S strain of P. chabaudi was studied. The principle method used in this study for investigating the immune response of the mice was to examine the immunity conferred on syngeneic mice, either X-irradiated or non-irradiated, by transferring to them lymphoid cells or serum from immune or semi-immune donors. The lymphoid cell populations examined were unfractionated spleen cells, nylon wool column enriched subpopulations of thymus-derived lymphocytes (T cells) and the so-called bursa-derived lymphocytes (B cells), bone marrow cells and phagocytic cells. In the course of these experiments observations were made on the effect of X-irradiation on the subsequent growth and multiplication of the parasite. In addition, an in vitro assay for antibody-dependent cell mediated cytotoxicity was used to investigate the activity of splenic K cells during malaria infection. K cells are lymphoid cells which may include lymphocytes of an undefined category, but possess receptors for the Fc portion of antibody on their surface and have the ability to non-specifically lyse target cells coated in antibodies. a) The adoptive transfer of immunity to P.chabaudi with immune spleen cells. Spleen cells from mice which had previously been infected with P.chabaudi were able to confer some immunity on syngeneic mice which had been irradiated with 600 or 800 rads. The protection was detected as a shortened patent parasitaemia in immune cell recipients compared to controls. The early experiments indicated the value of using irradiated recipients rather than non-irradiated recipients. In irradiated mice, a) smaller numbers of immune cells were required to promote detectable immunity than in non-irradiated mice, b) there was an amplification of the difference in the duration of primary parasitaemias in recipients of immune cells and normal cells compared to non-irradiated mice and c) as the irradiated host is immunodepressed, the protective effect of donor cells can be examined with a reduced contribution by the hosts own immune system. An initial non-specific resistance to P.chabaudi infection was observed in irradiated mice, although the infection in most of these mice was subsequently more severe than in non-irradiated mice. The non-specific resistance could be reduced or abolished by injecting lymphoid cells into mice shortly after irradiation or by infecting irradiated mice more than 15 days after irradiation. Other workers suggest that following irradiation, the reticulo-endothelial system is stimulated at the time that the non-specific resistance to P.chabaudi was observed. b) the adoptive transfer of immunity in syngeneic mice with enriched subpopulations of splenic immune T cells, B. cells, bone marrow cells and phagocytes. Immunity to P.chabaudi could be adoptively transferred with enriched spleen subpopulations of immune T cells or immune B cells in mice which had been irradiated 600 or 300 rads. The protective effects of unfractionated immune cells was, however, usually better than that of either immune T or F cell subpopulations. In most experiments enriched immune T cell recipients were more likely to suffer relapsing patent parasitaemias than either enriched immune B cell recipients or unfractionated immune cell recipients. In one experiment a comparison was made of the course of P.chabaudi infection in mice which had been irradiated with either 600 rads or 300 rads and which received injections of different immune cells. A dose of 600 rads permits the immune system of mice to recover from the effects of irradiation, but a dose of 800 rads is lethal to mice unless lymphoid cells are injected after irradiation. It was found that in recipients of enriched immune T or B cells, which had been irradiated with 600 rads, the parasitaemia became subpatent before their equivalents irradiated with 800 rads, but that there was little difference in parasitaemias between recipients of unfractionated immune cells given 600 or 800 rads. Experiments in which enriched immune T cells and B cells were recombined and injected into syngeneic mice gave inconclusive results as to whether the immune subpopulations acted synergistically. Similar experiments in which immune subpopulations of lymphoid cells were recombined with normal subpopulations of lymphoid cells demonstrated that the latter cells did not enhance the protective effect of the former cells. Bone marrow cells from immune mice were able to confer some protection on syngeneic recipients, but were not as protective as enriched immune T cells or B cells. The results obtained in adoptive transfer experiments using phagocytic cells from the spleen of immune mice depended on the length of time spleen cells were incubated in petri-dishes at 37° C before harvesting the phagocytes. Using C57B1 mice, phagocytes harvested after 15 hours incubation were as protective as unfractionated immune cells in a cell transfer experiment, but phagocytes harvested after 16 hours incubation were not protective. Examination of NIH phagocytic cells after 2.5 hours incubation at 37°C, which were as protective as unfractionated immune spleen cells in a cell transfer experiment, demonstrated that the petri-dish adherent cells may have contained B lymphocytes. c) The passive transfer of immunity with serum from P.chabaudi infected mice. The passive transfer of serum from C57B1 mice which had been previously infected with P.chabaudi to normal or irradiated syngeneic mice demonstrated that the serum recipients were initially protected from infection. Irradiated mice, however, were delayed longer in the onset of parasitaemia compared to non-irradiated mice. Using NIH mice, sera were collected from unfractionated immune spleen cell recipients, enriched immune T cell recipients and normal spleen recipients on the 11th day of a P.chabaudi infection, just after peak parasitaemia, and also on the 14th day of infection. On day 14, all immune cells recipients and most of the enriched immune T cell recipients had become subpatent but all normal cell recipients still had patent infections. Sera collected from the different spleen cell recipients on the 11th day of infection and passively transferred to irradiated mice demonstrated little protection. Sera collected on the 14th day of infect ion, however, reflected the immune status of the donors in their protective properties in mice infected with P.chabaudi. The serum from unfractionated immune cell recipients was the most protective of the 3 sera when compared to normal NIH serum and the serum from enriched immune T cell recipients was slightly protective, but the serum from normal cell recipients produced an enhanced infection in mice infected with P.chabaudi. d) Antibody-dependent cell-mediated cytotoxicity of spleen cells in P.chabaudi infected mice. In a preliminary investigation of K cell activity in the spleens of P.chabaudi infected mice, it was found that there was an increased activity of K cells collected at around peak parasitaemia compared to the activity of K cells in non-infected mice, and that this increased activity could also be found in mice which had recently become subpatent. As the target cell for antibody-dependent cell-mediated cytotoxicity employed was the thick red blood cell, it is not known whether the K cell is involved in the killing of P.chabaudi parasites. These results suggest that both T cells and B cells and antibody may be important in the immune response to P.chabaudi in mice. Primed T cells may act as helper cells in the production of malarial antibodies, but, as enriched primed T cells could confer protection on immunodepressed mice, it is possible that a cell-mediated mechanism of immunity may also exist.

The relationship between angiogenesis and the immune response in carcinogenesis and the progression of malignant disease

Recent studies have demonstrated that angiogenesis and suppressed cell- mediated immunity (CMI) play a central role in the pathogenesis of malignant disease facilitating tumour growth, invasion and metastasis. In the majority of tumours, the malignant process is preceded by a pathological condition or exposure to an irritant which itself is associated with the induction of angiogenesis and/or suppressed CMI. These include: cigarette smoking, chronic bronchitis and lung cancer; chronic oesophagitis and oesophageal cancer; chronic viral infections such as human papilloma virus and ano-genital cancers, chronic hepatitis B and C and hepatocellular carcinoma, and Epstein- Barr virus (EBV) and lymphomas; chronic inflammatory conditions such as Crohn's disease and ulcerative colitis and colorectal cancer; asbestos exposure and mesothelioma and excessive sunlight exposure/sunburn and malignant melanoma. Chronic exposure to growth factors (insulin-like growth factor-I in acromegaly), mutations in tumour suppressor genes (TP53 in Li Fraumeni syndrome) and long-term exposure to immunosuppressive agents (cyclosporin A) may also give rise to similar environments and are associated with the development of a range of solid tumours. The increased blood supply would facilitate the development and proliferation of an abnormal clone or clones of cells arising as the result of: (a) an inherited genetic abnormality; and/or (b) acquired somatic mutations, the latter due to local production and/or enhanced delivery of carcinogens and mutagenic growth factors. With progressive detrimental mutations and growth-induced tumour hypoxia, the transformed cell, to a lesser or greater extent, may amplify the angiogenic process and CMI suppression, thereby facilitating further tumour growth and metastasis. There is accumulating evidence that long-term treatment with cyclo-oxygenase inhibitors (aspirin and indomethacin), cytokines such as interferon-α, anti-oestrogens (tamoxifen and raloxifene) and captopril significantly reduces the incidence of solid tumours such as breast and colorectal cancer. These agents are anti-angiogenic and, in the case of aspirin, indomethacin and interferon-α have proven immunomodulatory effects. Collectively these observations indicate that angiogenesis and suppressed CMI play a central role in the development and progression of malignant disease. (C) 2000 Elsevier Science Ltd.

The koala immunological toolkit: Sequence identification and comparison of key markers of the koala (Phascolarctos cinereus) immune response

The koala (Phascolarctos cinereus) is an Australian marsupial that continues to experience significant population declines. Infectious diseases caused by pathogens such as Chlamydia are proposed to have a major role. Very few species-specific immunological reagents are available, severely hindering our ability to respond to the threat of infectious diseases in the koala. In this study, we utilise data from the sequencing of the koala transcriptome to identify key immunological markers of the koala adaptive immune response and cytokines known to be important in the host response to chlamydial infection in other species. This report describes the identification and preliminary sequence analysis of (1) T lymphocyte glycoprotein markers (CD4, CD8); (2) IL-4, a marker for the Th2 response; (3) cytokines such as IL-6, IL-12 and IL-1β, that have been shown to have a role in chlamydial clearance and pathology in other hosts; and (4) the sequences for the koala immunoglobulins, IgA, IgG, IgE and IgM. These sequences will enable the development of a range of immunological reagents for understanding the koala’s innate and adaptive immune responses, while also providing a resource that will enable continued investigations into the origin and evolution of the marsupial immune system.

Chlamydial infertility in women: Diagnosis, epidemiology and immune response

This project primarily focused on the development of a novel, non-invasive peptide-based ELISA to diagnose C. trachomatis-related infertility in women. In this study, an in silico approach was applied to identify and design novel peptide antigens that are specific to women with C. trachomatis-related infertility. The serological assay was developed such that it could potentially replace invasive techniques for early infertility investigation. The thesis further investigated the sero-prevalence of chlamydial infertility in women from a low-resource, high prevalence setting. In addition, the thesis also identified immune markers that were associated with the C. trachomatis-related infertility in women.

Early cellular immune response to a new candidate mycobacterial vaccine antigen in childhood tuberculosis

The search for novel vaccines against tuberculosis (TB) would benefit from in-depths knowledge of the human immune responses to Mycobacterium tuberculosis (Mtb) infection. Here, we characterised in a low TB incidence country, the immune responses to a new candidate vaccine antigen against TB, the heparin-binding haemagglutinin (HBHA), in young children in contact with an active TB case (aTB). Children with no history of BCG vaccination were compared to those vaccinated at birth to compare the initial immune responses to HBHA with secondary immune responses. Fifty-eight children with aTB and 76 with latent TB infection (LTBI) were included and they were compared to 90 non-infected children. Whereas Mtb-infected children globally secreted more interferon-gamma (IFN-γ) in response to HBHA compared to the non-infected children, these IFN-γ concentrations were higher in previously BCG-vaccinated compared to non-vaccinated children. The IFN-γ concentrations were similar in LTBI and aTB children, but appeared to differ qualitatively. Whereas the IFN-γ secretion induced by native methylated and recombinant non-methylated HBHA were well correlated for aTB, this was not the case for LTBI children. Thus, Mtb-infected young children develop IFN-γ responses to HBHA that are enhanced by prior BCG vaccination, indicating BCG-induced priming, thereby supporting a prime-boost strategy for HBHA-based vaccines. The qualitative differences between aTB and LTBI in their HBHA-induced IFN-γ responses may perhaps be exploited for diagnostic purposes.

Expression of galectin-3 in the tumor immune response in colon cancer.

The role of tumor-associated macrophages (TAMs) is controversial. Although most studies on different cancer types associate them with a poorer prognosis, interestingly in colon cancer, most articles indicate that TAMs prevent tumor development; patients with high TAMs have better prognosis and survival rate. M1-polarized macrophages produce high level of tumor necrosis factor-alpha, interleukin-1 beta or reactive oxygen species, which can effectively kill susceptible tumor cells. In contrast, M2-polarized macrophages can secrete different factors that promote tumor cell growth and survival or favor angiogenesis and tissue invasion. Considering the beneficial role of TAMs in colon cancer, we speculated that they may not display the M2 polarization commonly observed in tumor microenvironment, but rather develop M1 properties. Therefore, we used an in vitro model to analyze the effects of supernatants from M1-polarized macrophages on DLD-1 colon cancer cells. Our data indicate that the conditioned medium from LPS-activated macrophages (CM-LAM) contains a high level of granulocyte-macrophage colony-stimulating factor, interleukins-1 beta, -6, -8 and tumor necrosis factor-alpha, and that it exerts a marked growth inhibitory activity on DLD-1 cells. Prolonged exposure to CM-LAM results in cell death by apoptosis. Such exposure to CM-LAM leads to the modulation of gal-3 expression: we observed a marked downregulation of gal-3 mRNA and protein expression following CM-LAM treatment. We also describe that the knockdown of gal-3 sensitizes DLD-1 cells to CM-LAM. These data suggest an involvement of gal-3 in the response of colon cancer cells to proinflammatory stimuli, such as the conditioned medium from activated macrophages.

Surface plasmon resonance-based inhibition assay for real-time detection of Cryptosporidium parvum oocyst

A surface plasmon resonance (SPR)-based inhibition assay method using a polyclonal anti-mouse IgM arrayed Cryptosporidium sensor chip was developed for the real-time detection of Cryptosporidium parvum oocysts. The Cryptosporidium sensor chip was fabricated by subsequent immobilization of streptavidin and polyclonal anti-mouse IgM (secondary antibody) onto heterogeneous self-assembled monolayers (SAMs). The assay consisted of the immunoreaction step between monoclonal anti-C. parvum oocyst (primary antibody) and oocysts, followed by the binding step of the unbound primary antibody onto the secondary antibody surface. It enhanced not only the immunoreaction yield of the oocysts by batch reaction but also the accessibility of analytes to the chip surface by antibody–antibody interaction. Furthermore, the use of optimum concentration of the primary antibody maximized its binding response on the chip. An inversely linear calibration curve for the oocyst concentration versus SPR signal was obtained in the range of 1×106–1×102 oocysts ml-1. The oocyst detection was also successfully achieved in natural water systems. These results indicate that the SPR-based inhibition assay using the Cryptosporidium sensor chip has high application potential for the real-time analysis of C. parvum oocyst in laboratory and field water monitoring.

Development of a bifunctional CD1d-anti-HER2 scFv fusion molecule to redirect the iNKT cell-mediated immune response to the tumor site

Abstract : Invariant natural killer T lymphocytes (iNKT) are a unique subpopulation of T lymphocytes recognizing glycolipid antigens in the context of the MHC class I-like molecule CD1d. Upon activation with the high affinity ligand α-galactosylceramide (αGalCer), iNKT cells rapidly produce large amounts of the pro-inflammatory cytokine interferon gamma (IFN-γ) and potently activate cells of the innate and adaptive immune response, such as dendritic cells (DCs), NK and T cells. In this context, iNKT cells have been shown to efficiently mediate antitumor activity, and recent research has focused on the manipulation of these cells for antitumor therapies. However, a major drawback of αGalCer as a free drug is that a single injection of this ligand leads to a short-lived iNKT cell activation followed by a long-term anergy, limiting its therapeutic use. In contrast, we demonstrate here that when αGalCer is loaded on a recombinant soluble CD1d molecule (αGalCer/sCD1d), repeated injections lead to a sustained iNKT and NK cell activation associated with IFN-γ secretion as well as with DC maturation. Most importantly, when the αGalCer/sCD1d is fused to an anti-HER2 scFv antibody fragment, potent inhibition of experimental lung metastasis and established subcutaneous tumors is obtained when systemic treatment is started two to seven days after the injection of HER2-expressing B16 melanoma cells, whereas at this time free αGalCer has no effect. The antitumor activity of the sCD1d-anti-HER2 fusion protein is associated with HER2-specific tumor localization and accumulation of iNKT, NK and T cells at the tumor site. Importantly, active T cell immunization combined with the sCD1d-anti-HER2 treatment leads to the accumulation of antigen-specific CD8 T cells exclusively in HER2-expressing tumors, resulting in potent tumor inhibition. In conclusion, sustained activation and tumor targeting of iNKT cells by recombinant αGalCer/sCD1d molecules thus may promote a combined innate and adaptive immune response at the tumor site that may prove to be effective in cancer immunotherapy. RESUME : Les lymphocytes «invariant Natural Killer T » (iNKT) forment une sous-population particulière de lymphocytes T reconnaissant des antigènes glycolipidiques présentés sur la molécule non-polymorphique CD1d, analogue aux protéines du complexe majeur d'histocompatibilité de classe I. Après activation avec le ligand de haute affinité α-galactosylceramide (αGalCer), les cellules iNKT produisent des grandes quantités de la cytokine pro-inflammatoire interferon gamma (IFN-γ) et activent les cellules du système immunitaire inné et acquis, telles que les cellules dendritiques (DC), NK et T. En conséquence, on a montré que les cellules iNKT exercent des activités anti-tumorales et la recherche s'est intéressée à la manipulation de ces cellules pour développer des thérapies anti-tumorales. Néanmoins, le désavantage majeur de l'αGalCer, injecté seul, est qu'une seule dose de ce ligand aboutit à une activation des cellules iNKT de courte durée suivie par un état anergique prolongé, limitant l'utilisation thérapeutique de ce glycolipide. En revanche, l'étude présentée ici démontre que, si l'αGalCer est chargé sur des molécules récombinantes soluble CD1d (αGalCer/sCDld), des injections répétées aboutissent à une activation prolongée des cellules iNKT et NK associée avec la sécrétion d'IFN-γ et la maturation des cellules DC. Plus important, si on fusionne la molécule αGalCer/sCD1d avec un fragment single-chain (scFv) de l'anticorps anti-HER2, on observe une importante inhibition de métastases expérimentales aux poumons et de tumeurs sous-cutanées même lorsque le traitement systémique est commencé 2 à 7 jours après la greffe des cellules de mélanome B16 transfectées avec l'antigène HER2. Dans les mêmes conditions le traitement avec l'αGalCer seul est inefficace. L'activité anti-tumorale de la protéine sCDld-anti-HER2 est associée à son accumulation spécifique dans des tumeurs exprimant le HER2 ainsi qu'avec une accumulation des cellules iNKT, NK et T à la tumeur. De plus, une immunisation active combinée avec le traitement sCD1d-anti-HER2 aboutit à une accumulation des lymphocytes T CD8 spécifiques de l'antigène d'immunisation, ceci exclusivement dans des tumeurs qui expriment l'antigène HER2. Cette combinaison résulte dans une activité anti-tumeur accrue. En conclusion, l'activation prolongée des cellules iNKT redirigées à la tumeur par des molécules recombinantes αGalCer/sCDld conduit à l'activation de la réponse innée et adaptative au site tumoral, offrant une nouvelle stratégie prometteuse d'immunothérapie contre le cancer. RESUME POUR UN LARGE PUBLIC : Le cancer est une cause majeure de décès dans le monde. Sur un total de 58 millions de décès enregistrés au niveau mondial en 2005, 7,6 millions (soit 13%) étaient dus au cancer. Les principaux traitements de nombreux cancers sont la chirurgie, en association avec la radiothérapie et la chimiothérapie. Néanmoins, ces traitements nuisent aussi aux cellules normales de notre corps et parfois, ils ne suffisent pas pour éliminer définitivement une tumeur. L'immunothérapie est l'une des nouvelles approches pour la lutte contre le cancer et elle vise à exploiter la spécificité du système immunitaire qui peut distinguer des cellules normales et tumorales. Une cellule exprimant un marqueur tumoral (antigène) peut être reconnue par le système immunitaire humoral (anticorps) et/ou cellulaire, induisant une réponse spécifique contre la tumeur. L'immunothérapie peut s'appuyer alors sur la perfusion d'anticorps monoclonaux dirigés contre des antigènes tumoraux, par exemple les anticorps dirigés contre les protéines oncogéniques Her-2/neu dans le cancer du sein. Ces anticorps ont le grand avantage de spécifiquement se localiser à la tumeur et d'induire la lyse ou d'inhiber la prolifération des cellules tumorales exprimant l'antigène. Aujourd'hui, six anticorps monoclonaux non-conjugés sont approuvés en clinique. Cependant l'efficacité de ces anticorps contre des tumeurs solides reste limitée et les traitements sont souvent combinés avec de la chimiothérapie. L'immunothérapie spécifique peut également être cellulaire et exploiter par immunisation active le développement de lymphocytes T cytotoxiques (CTL) capables de détruire spécifiquement les cellules malignes. De telles «vaccinations »sont actuellement testées en clinique, mais jusqu'à présent elles n'ont pas abouti aux résultats satisfaisants. Pour obtenir une réponse lymphocytaire T cytotoxique antitumorale, la cellule T doit reconnaître un antigène associé à la tumeur, présenté sous forme de peptide dans un complexe majeur d'histocompatibilité de classe I (CHM I). Cependant les cellules tumorales sont peu efficace dans la présentation d'antigène, car souvent elles se caractérisent par une diminution ou une absence d'expression des molécules d'histocompatibilité de classe I, et expriment peu ou pas de molécules d'adhésion et de cytokines costimulatrices. C'est en partie pourquoi, malgré l'induction de fortes réponses CTL spécifiquement dirigés contre des antigènes tumoraux, les régressions tumorales obtenus grâce à ces vaccinations sont relativement rares. Les lymphocytes «invariant Natural Killer T » (iNKT) forment une sous-population particulière de lymphocytes T reconnaissant des antigènes glycolipidiques présentés sur la molécule non-polymorphique CD1d, analogue aux protéines CMH I. Après activation avec le ligand de haute affinité α-galactosylceramide (αGalCer), les cellules iNKT produisent des grandes quantités de la cytokine pro-inflammatoire interferon gamma (IFN-γ) et activent les cellules du système immunitaire inné et acquis, telles que les cellules dendritiques (DC), NK et T. En conséquence, on a montré que les cellules iNKT exercent des activités anti-tumorales et la recherche s'est intéressée à la manipulation de ces cellules pour développer des thérapies anti-tumorales. Néanmoins, le désavantage majeur de l'αGalCer, injecté seul, est qu'une seule dose de ce ligand aboutit à une activation des cellules iNKT de courte durée suivie par un état anergique prolongé, limitant l'utilisation thérapeutique de ce glycolipide. Notre groupe de recherche a donc eu l'idée de développer une nouvelle approche thérapeutique où la réponse immunitaire des cellules iNKT serait prolongée et redirigée vers la tumeur par des anticorps monoclonaux. Concrètement, nous avons produit des molécules récombinantes soluble CD1d (sCD1d) qui, si elles sont chargés avec l'αGalCer (αGalCer/sCDld), aboutissent à une activation prolongée des cellules iNKT et NK associée avec la sécrétion d'IFN-γ et la maturation des cellules DC. Plus important, si la molécule αGalCer/sCD1d est fusionnée avec un fragment single-chain (scFv) de l'anticorps anti-HER2, la réponse immunitaire est redirigée à la tumeur pour autant que les cellules cancéreuses expriment l'antigène HER2. Les molécules αGalCer/sCDld ainsi présentées activent les lymphocytes iNKT. Avec cette stratégie, on observe une importante inhibition de métastases expérimentales aux poumons et de tumeurs sous-cutanées, même lorsque le traitement systémique est commencé 2 à 7 jours après la greffe des cellules de mélanome B16 transfectées avec l'antigène HER2. Dans les mêmes conditions le traitement avec l'αGalCer seul est inefficace. L'activité anti-tumorale de la protéine sCDld-anti-HER2 est associée à son accumulation spécifique dans des tumeurs exprimant le HER2 ainsi qu'avec une accumulation des cellules iNKT, NK et T à la tumeur. En conclusion, l'activation prolongée des cellules iNKT redirigées à la tumeur par des molécules récombinantes αGalCer/sCD1d conduit à l'activation de la réponse innée et adaptative au site tumoral, offrant une nouvelle stratégie prometteuse d'immunothérapie contre le cancer.