The role of vaccines in the control of STDs: HPV vaccines

Prophylactic vaccines for genital human papillomavirus (HPV) infection have been shown to be feasible in animal models, and suitable vaccine material based on virus-like particles can be produced in bulk at reasonable cost. Initiation of phase III clinical trials will follow definition of trial outcome measures through further epidemiological studies, and development-of assays of host protective immunity. Vaccines could in principle eliminate HPV-related disease, as the human race is the only natural host for the relevant papillomaviruses (PVs). Therapeutic vaccines for genital HPV infection are also possible, but have not yet been demonstrated as feasible in practice because the choice of vaccine antigens is difficult, the method of their optimal delivery is uncertain, and the nature of the relevant antiviral immunity is unknown. PV species specificity will require trials to be conducted in man, which will slow definition of an ideal vaccine.

Presentation of the HPV16E7 protein by skin grafts is insufficient to allow graft rejection in an E7-primed animal

The E7 transforming protein of Human Papillomavirus type 16 (HPV16) is expressed in the skin of a line of RIB mice transgenic for the E6 and E7 open reading frames of HPV16 driven from the alpha A crystallin promoter (FVB alpha AcryHPV16E6E7). We have transferred skin from FVB alpha AcryHPV16E6E7 mice to naive or E7-primed syngeneic NE recipients to assess whether the E7 protein of HPV16 can function as a minor transplantation antigen (MTA) and promote skin graft rejection. FVB mice did not reject E7 expressing tail or flank skin grafts. E7 immunized FVB x C57BL/6J mice recipients of FVB alpha AcryHPV16E6E7 x C57BL/6J skin generated humoral and DTH responses to E7 in vivo and E7-specific CTL precursors in the spleen, but failed to reject 57 expressing tail skin grafts by 100 days posttransfer. Thus although HPV16 E7 + ve mesenchymal and endodermal tumors can be eliminated by an E7-specific immune response, the same protein is unable to act as a MTA and promote graft rejection when expressed in skin cells. Lack of rejection of grafts expressing MTAs such as E7 may be relevant to the immunology of epithelial tumors expressing tumor-specific antigens and to our understanding of the immunology of diseases of the skin. (C) 1997 Academic Press.

Kaposi sarcoma and paracoccidioidomycosis in the same fragment of oral mucosa biopsy: a rare association in human immunodeficiency virus-positive patient. A case report

The immunossuppression caused by HIV infection makes the affected individuals more susceptible to some diseases including infections, neoplasms, or even the association between them. Kaposi sarcoma (KS) is the most common AIDS-related neoplasm, featured as an angioproliferative disorder. Its cause seems to be related to the human herpesvirus type 8 and it is usually associated with lower CD4+ T cell count. Oral involvement is frequent, presenting red to blue-purplish plaques, maculaes, and nodules. On the other hand, paracoccidioidomycosis (PCM) is a systemic mycosis, endemic in Latin America, caused by Paracoccidioides brasiliensis. This mycosis is not commonly related to human immunodeficiency virus (HIV) infection, although PCM can be present in immunosuppression cases. Oral lesions, as granulomatous ulcers, are often identified in seropositive patients with PCM. A rare case, in which a male HIV-positive patient presented simultaneously Kaposi sarcoma and PCM in the same fragment of oral mucosa biopsy, is described. To the best of our knowledge, this concomitant association had not been previously described. (C) 2011 Elsevier Inc. All rights reserved.

Tolerance or immunity to a tumor antigen expressed in somatic cells can be determined by systemic proinflammatory signals at the time of first antigen exposure

Mice transgenic for the E7 tumor Ag of human papillomavirus type 16, driven from a keratin 14 promoter, express E7 in keratinocytes but not dendritic cells. Grafted E7-transgenic skin is not rejected by E7-immunized mice that reject E7-transduced transplantable tumors. Rejection of recently transplanted E7-transgenic skin grafts, but not of control nontransgenic grafts or of established E7-transgenic grafts, is induced by systemic administration of live or killed Listeria monocytogenes or of endotoxin. Graft recipients that reject an E7 graft reject a subsequent E7 graft more rapidly and without further L. monocytogenes exposure, whereas recipients of an E7 graft given without L. monocytogenes do not reject a second graft, even if given with L. monocytogenes. Thus, cross-presentation of E7 from keratinocytes to the adaptive immune system occurs with or without a proinflammatory stimulus, but proinflammatory stimuli at the time of first cross-presentation of Ag can determine the nature of the immune response to the Ag. Furthermore, immune effector mechanisms responsible for rejection of epithelium expressing a tumor Ag in keratinocytes are different from those that reject an E7-expressing transplantable tumor. These observations have implications for immunotherapy for epithelial cancers.

Laminin 10/11: an alternative adhesive ligand for epidermal keratinocytes with a functional role in promoting proliferation and migration

We have investigated the expression and function of the isoforms of laminin bearing the alpha(5) chain, i.e. laminin-10/11 in neonatal and adult human skin. By immunostaining human skin derived from a variety of anatomic sites, we found that the laminin-alpha(5) chain is expressed abundantly in the basement membrane underlying the interfollicular epidermis and the blood vessels in the dermis. Interestingly, while the expression level of the well-studied laminin-5 isoform did not change significantly with age, laminin-10/11 (a5 chain) appeared to decrease in the basement membrane underlying the epidermis, in adult skin. In contrast, the levels of laminin-10/11 in the basement membrane underlying blood vessels remained unchanged in neonatal vs. adult skin. Importantly, in vitro cell adhesion assays demonstrated that laminin-10/11 is a potent adhesive substrate for both neonatal and adult keratinocytes and that this adhesion is mediated by the alpha(3)beta(1), and alpha(6)beta(4) integrins. Adhesion assays performed with fractionated basal keratinocytes showed that stem cells, transit amplifying cells and early differentiating cells all adhere to purified laminin-10/11 via these receptors. Further, laminin-10/11 provided a proliferative signal for neonatal foreskin keratinocytes, adult breast skin keratinocytes, and even a human papillomavirus type-18 transformed tumorigenic keratinocyte cell line in vitro. Finally, laminin-10/11 was shown to stimulate keratinocyte migration in an in vitro wound healing assay. These results provide strong evidence for a functional role for laminin-10/11 in epidermal proliferation during homeostasis, wound healing and neoplasia.

IL-10 Mediates Suppression of the CD8 T Cell IFN-γ Response to a Novel Viral Epitope in a Primed Host

Priming to Ag can inhibit subsequent induction of an immune response to a new epitope incorporated into that Ag, a phenomenon referred to as original antigenic sin. In this study, we show that prior immunity to a virus capsid can inhibit subsequent induction of the IFN-gamma effector T cell response to a novel CD8-restricted antigenic epitope associated with the virus capsid. Inhibition does not involve Ab to the virus capsid, as it is observed in animals lacking B cells. CD8-restricted virus-specific T cell responses are not required, as printing to virus without CTL induction is associated with inhibition. However, IL-10(-/-) mice, in contrast to IL-10(+/+) mice, generate CD8 T cell and Ab responses to novel epitopes incorporated into a virus capsid, even when priming to the capsid has resulted in high titer Ab to the capsid. Furthermore, capsid-primed mice, unable to mount a response to a novel epitope in the capsid protein, are nevertheless able to respond to the same novel epitope delivered independently of the capsid. Thus, inhibition of responsiveness to a novel epitope in a virus-primed animal is a consequence of secretion of IL-10 in response to presented Ag, which inhibits local generation of new CD8 IFN-gamma-secreting effector T cells. Induction of virus- or tumor Ag-specific CD8 effector T cells in the partially Ag-primed host may thus be facilitated by local neutralization of IL-10.

Enhanced effector and memory CTL responses generated by incorporation of receptor activator of NF-kappa B(RANK)/RANK ligand costimulatory molecules into dendritic cell immunogens expressing a human tumor-specific antigen

The outcome of dendritic cell (DC) presentation of Ag to T cells via the TCR/MHC synapse is determined by second signaling through CD80/86 and, importantly, by ligation of costimulatory ligands and receptors located at the DC and T cell surfaces. Downstream signaling triggered by costimulatory molecule ligation results in reciprocal DC and T cell activation and survival, which predisposes to enhanced T cell-mediated immune responses. In this study, we used adenoviral vectors to express a model tumor Ag (the E7 oncoprotein of human papillomavirus 16) with or without coexpression of receptor activator of NF-kappaB (RANK)/RANK ligand (RANKL) or CD40/CD40L costimulatory molecules, and used these transgenic DCs to immunize mice for the generation of E7-directed CD8(+) T cell responses. We show that coexpression of RANK/RANKL, but not CD40/CD40L, in E7-expressing DCs augmented E7-specific IFN-gamma-secreting effector and memory T cells and E7-specific CTLs. These responses were also augmented by coexpression of T cell costimulatory molecules (RANKL and CD40L) or DC costimulatory molecules (RANK and CD40) in the E7-expressing DC immunogens. Augmentation of CTL responses correlated with up-regulation of CD80 and CD86 expression in DCs transduced with costimulatory molecules, suggesting a mechanism for enhanced T cell activation/survival. These results have generic implications for improved tumor Ag-expressing DC vaccines, and specific implications for a DC-based vaccine approach for human papillomavirus 16-associated cervical carcinoma.

Phenotypic and molecular characterization of Salmonella Enteritidis strains isolated in São Paulo, Brazil

In São Paulo State, Brazil, the epidemic increase in isolation of Salmonella Enteritidis has been observed since 1994. A total of 105 S. Enteritidis strains (72 from human and 33 from non-human sources) isolated during the period 1975-1995, previously characterized by phage typing, was analyzed by antimicrobial susceptibility, plasmid profile, and ribotyping. Over 70% of the strains were susceptible to all antimicrobial agents tested, however, multiple resistance to antimicrobials was observed among the studied strains, mainly those from hospitalized patients. Phage type 8 (PT-8) was predominant among the strains isolated during the period of 1975-1992, but in the following years, PT-4 was the most frequent phage type identified. Seven different plasmid profiles were detected and 96% of the isolates harbored a plasmid of approximately 36 MDa. Ribotyping discriminated fourteen ribotypes (R1 to R14) among the strains examined. By analysis of dendrogram the strains were included in three groups with similarity level of 60%. The obtained results indicate that, a single ribotype (R11), determined for PT-4 strains isolated from 1993, characterizes the epidemic clone of S. Enteritidis in our region.

Community prevalence of methicillin and vancomycin resistant Staphylococcus aureus in and around Bangalore, southern India

INTRODUCTION: Staphylococcus aureus is a known colonizer in humans and has been implicated in community acquired soft tissue infections. However emergence of methicillin resistant S. aureus (MRSA) has aroused great concern worldwide. This study aimed to determine the prevalence of MRSA in the community of Bangalore, southern India. METHODS: Swabs were collected from anterior nares, forearm, dorsum and palm of the hands of 1,000 healthy individuals residing in and around Bangalore, belonging to different socioeconomic strata and age groups. RESULTS: Analysis verified that 22.5% and 16.6% of the individuals presented Staphylococcus aureus and MRSA, respectively, at any of the three sites. Vancomycin resistance was observed in 1.4% of the S. aureus isolates, which was confirmed by detection of the vanA gene. It was interesting to note that 58.8% of the children in the age group 1-5 years-old presented MRSA, the highest percentage compared to other age groups of < 1 (44.4%) year-old, 5-20 (21.7%) years-old, > 40 (11%) years-old and 20-40 (9.9%) years-old. Among the population of various socioeconomic strata, maximum MRSA colonization was observed among doctors (22.2%), followed by upper economic class (18.8%), lower economic class (17.7%), apparently healthy hospital in-patients (16.5%), nurses (16%) and middle economic class (12.5%). Most of the MRSA isolates were capsular polysaccharide antigen type 8 (57.1%). CONCLUSIONS: There is a need for continuous surveillance and monitoring of the presence of MRSA in the community and a clearer understanding of the dynamics of the spread of MRSA will assist in controlling its dissemination.

Current status of herpesvirus identification in the oral cavity of HIV-infected children

INTRODUCTION: Some viruses of the Herpesviridae family are frequently the etiologic agents of oral lesions associated with HIV. The aim of this study was to identify the presence of herpes simplex virus types 1 and 2 (HSV-1, HSV-2), Varicella Zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus type 6, type 7 and type 8 (HHV-6, HHV-7 and HHV-8) in the oral cavity of HIV-infected children/adolescents and verify the association between viral subtypes and clinical factors. METHODS: The cells of oral mucosa were collected from 50 HIV infected children/adolescents, 3-13 years old (mean age 8.66). The majority (66%) of selected were girls, and they were all outpatients at the pediatric AIDS clinic of a public hospital in Rio de Janeiro. Nested-PCR was used to identify the viral types. RESULTS: Absence of immunosuppression was observed in 66% of the children. Highly active antiretroviral therapy (HAART) was used by 72.1% of selected and moderate viral load was observed in 56% of the children/adolescents. Viral types were found in 86% of the children and the subtypes were: HSV-1 (4%), HSV-2 (2%), VZV (4%), EBV (0%), HCMV (24%), HHV6 (18%), HHV-7 (68%), HHV8 (0%). CONCLUSIONS: The use of HAART has helped to reduce oral lesions, especially with herpes virus infections. The health professionals who work with these patients should be aware of such lesions because of their predictive value and the herpes virus can be found circulating in the oral cavity without causing lesions.

Monitoring of vaccine-specific gamma interferon induction in genital mucosa of mice by real-time reverse transcription-PCR.

Monitoring of T-cell responses in genital mucosa has remained a major challenge because of the absence of lymphoid aggregates and the low abundance of T cells. Here we have adapted to genital tissue a sensitive real-time reverse transcription-PCR (TaqMan) method to measure induction of gamma interferon (IFN-gamma) mRNA transcription after 3 h of antigen-specific activation of CD8 T cells. For this purpose, we vaccinated C57BL/6 mice subcutaneously with human papillomavirus type 16 L1 virus-like particles and monitored the induction of CD8 T cells specific to the L1(165-173) H-2D(b)-restricted epitope. Comparison of the responses induced in peripheral blood mononuclear cells and lymph nodes (LN) by L1-specific IFN-gamma enzyme-linked immunospot assay and TaqMan determination of the relative increase in L1-specific IFN-gamma mRNA induction normalized to the content of CD8b mRNA showed a significant correlation, despite the difference in the readouts. Most of the cervicovaginal tissues could be analyzed by the TaqMan method if normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA was used and a significant L1-specific IFN-gamma induction was found in one-third of the immunized mice. This local response did not correlate with the immune responses measured in the periphery, with the exception of the sacral LN, an LN draining the genital mucosa, where a significant correlation was found. Our data show that the TaqMan method is sensitive enough to detect antigen-specific CD8 T-cell responses in the genital mucosa of individual mice, and this may contribute to elaborate effective vaccines against genital pathogens.

The efficiency of a novel delivery system (PEI600-Tat) in development of potent DNA vaccine using HPV16 E7 as a model antigen.

DNA vaccination is a promising approach for inducing both humoral and cellular immune responses. The mode of plasmid DNA delivery is critical to make progress in DNA vaccination. Using human papillomavirus type 16 E7 as a model antigen, this study evaluated the effect of peptide-polymer hybrid including PEI600-Tat conjugate as a novel gene delivery system on the potency of antigen-specific immunity in mice model. At ratio of 10:50 PEI-Tat/E7DNA (w/w), both humoral and cellular immune responses were significantly enhanced as compared with E7DNA construct and induced Th1 response. Therefore, this new delivery system could have promising applications in gene therapy.

Inflammation And Autoimmune Responses Are Independent Of Peripheral Mhc Class Ii Expression Driven By Ciita Piv In Collagen Induced Arthritis

Background In rheumatoid arthritis (RA), non-professional antigen presenting cells (APCs) such as fi broblast-like synoviocytes (FLS) can express MHC class II (MHCII) molecules and function as non-professional APCs in vitro.Objective To examine the regulation of MHCII expression in FLS and to investigate the role of FLS as non-professional APCs in collagen-induced arthritis (CIA). Methods Expression of MHCII, CIITA and Ciita isoforms pI, pIII and pIV was examined by RT-qPCR, immunohistochemistry and fl ow cytometry in human synovial tissues, arthritic mouse joints and human as well as mouse FLS. CIA was induced in mice knockout for the isoform IV of Ciita (pIV-/-), in pIV-/- mice transgenic for CIITA in the thymus (pIV-/- K14 CIITA) and in control littermates in the DBA/1 background by immunising with bovine collagen type II (CII) in complete Freund's adjuvant.Results HLA-DRA, total CIITA and CIITA pIII mRNA levels were signifi cantly increased in the synovial tissues from RA compared to osteoarthritis patients. Human FLS expressed surface MHCII via CIITA pIII and pIV, while MHCII expression in murine FLS was entirely mediated by pIV. pIV-/- mice lacked both inducible MHCII expression on non-professional APCs including FLS, and in the thymic cortex. The thymic defect in pIV-/- mice impaired CD4+ positive selection, thus protecting pIV-/- mice from CIA by preventing CD4+ T cells immune responses against CII and blocking the release of IFN-γ and IL-17 in ex vivo stimulated lymph node cells. The production of T dependent, arthritogenic anti-CII antibodies was also impaired in pIV-/- mice. A normal thymic expression of MHCII and CD4+ T cell repertoire was obtained in pIV-/- K14 CIITA Tg mice. Immune responses against CII were restored in pIV-/- K14 CIITA Tg mice, as well as the arthritis incidence and clinical severity despite the lack of MHCII expression by mouse FLS. At histology, infl ammation andneutrophils infi ltration scores were not reduced in pIV-/- K14 CIITA Tg mice, while the bone erosion score was signifi cantly lower than in controls.Conclusion Over expression of MHCII is tightly correlated with CIITA pIII in the arthritic human synovium. MHCII is induced via CIITA pIII and pIV in human FLS. In the mouse, MHCII expression in the thymic cortex and in FLS is strictly dependent upon Ciita pIV. The lack of Ciita pIV in the periphery of pIV-/- K14 CIITA Tg mice lowered the bone erosion score but did not signifi cantly protect from infl ammation and autoimmune responses in CIA.

Kaposi's sarcoma-associated herpesvirus infection and Kaposi's sarcoma in Brazil

Kaposi's sarcoma (KS) became a critical health issue with the emergence of acquired immunodeficiency syndrome (AIDS) in the 1980s. Four clinical-epidemiological forms of KS have been described: classical KS, endemic KS, iatrogenic KS, and AIDS-associated KS. In 1994, Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus type 8 was identified by Chang and colleagues, and has been detected worldwide at frequencies ranging from 80 to 100%. The aim of the present study was to evaluate the frequency of KSHV infection in KS lesions from HIV-positive and HIV-negative patients in Brazil, as well as to review the current knowledge about KS transmission and detection. For these purposes, DNA from 51 cases of KS was assessed by PCR: 20 (39.2%) cases of classical KS, 29 (56.9%) of AIDS-associated KS and 2 (3.9%) of iatrogenic KS. Most patients were males (7.5:1, M/F), and mean age was 47.9 years (SD = ± 18.7 years). As expected, HIV-positive KS patients were younger than patients with classical KS. On the other hand, patients with AIDS-associated KS have early lesions (patch and plaque) compared to classical KS patients (predominantly nodular lesions). This is assumed to be the result of the early diagnose of KS in the HIV-positive setting. KSHV infection was detected by PCR in almost all cases (48/51; 94.1%), irrespectively of the clinical-epidemiological form of KS. These results show that KSHV is associated with all forms of KS in Brazilian patients, a fact that supports the role of this virus in KS pathogenesis.

Identification du rôle et des modifications post-traductionnelles modulant l’export nucléaire de l’hélicase virale E1 au cours du cycle de réplication du virus du papillome humain

Les virus du papillome humain (VPH) sont de petits virus à ADN double brin infectant les épithéliums de la peau et des muqueuses. La réplication nécessaire au maintien de leur génome dans les cellules infectées dépend des protéines virales E1 et E2. Au cours de la réplication, E1 est recrutée à l’origine de réplication par E2 afin d’être assemblée en doubles hexamères capables de dérouler l’ADN. E1 contient un domaine C-terminal responsable de l’activité ATPase/hélicase, un domaine central de liaison à l’origine et une région N-terminale régulant la réplication in vivo. Cette région contient des signaux de localisation et d’export nucléaire qui modulent le transport intracellulaire de E1. Chez le virus du papillome bovin (VPB), il a été proposé que ce transport est régulé par la sumoylation de E1. Finalement, la région N-terminale de E1 contient un motif de liaison aux cyclines permettant son interaction avec la cycline E/A-Cdk2. La phosphorylation de E1 par cette dernière régule différemment l’export nucléaire des protéines E1 du VPB et du VPH. Dans la première partie de cette étude, nous avons démontré que bien que la protéine E1 des VPH interagit avec Ubc9, l’enzyme de conjugaison de la voie de sumoylation, cette voie n’est pas requise pour son accumulation au noyau. Dans la seconde partie, nous avons déterminé que l’accumulation nucléaire de E1 est plutôt régulée pas sa phosphorylation. En fait, nous avons démontré que l’export nucléaire de E1 est inhibé par la phosphorylation de sérines conservées de la région N-terminale de E1 par Cdk2. Puis, nous avons établi que l’export nucléaire de E1 n’est pas nécessaire à l’amplification du génome dans les kératinocytes différenciés mais qu’il est requis pour le maintien du génome dans les kératinocytes non différenciés. En particulier, nous avons découvert que l’accumulation nucléaire de E1 inhibe la prolifération cellulaire en induisant un arrêt du cycle cellulaire en phase S et que cet effet anti-prolifératif est contrecarrée par l’export de E1 au cytoplasme. Dans la troisième partie de cette étude, nous avons démontré que l’arrêt cellulaire induit par E1 dépend de sa liaison à l’ADN et à l’ATP, et qu’il est accompagné par l’activation de la voie de réponse aux dommages à l’ADN dépendante de ATM (Ataxia Telangiectasia Mutated). Ces deux événements semblent toutefois distincts puisque la formation d’un complexe E1-E2 réduit l’activation de la voie de réponse aux dommages par E1 sans toutefois prévenir l’arrêt de cycle cellulaire. Finalement, nous avons démontré que la réplication transitoire de l’ADN viral peut avoir lieu dans des cellules arrêtées en phase S, indépendamment de l’activation de la voie de réponse aux dommages à l’ADN et de la kinase ATM. Globalement, nos résultats démontrent que l’export nucléaire de E1 est régulé par sa phosphorylation et non par sa sumoylation. Ils démontrent également que l’export nucléaire de E1 est essentiel au maintien du génome dans les kératinocytes, possiblement parce qu’il prévient l’inhibition de la prolifération cellulaire et l’activation de la voie de réponse aux dommages à l’ADN en limitant l’accumulation de E1 au noyau.