CTA1-DD is an effective adjuvant for targeting anti-chlamydial immunity to the murine genital mucosa

Chlamydia trachomatis is a significant human pathogen with potentially severe disease sequelae in the genital tract, including infertility. A successful vaccine will need to effectively target immunity to the genital mucosa. Intranasal immunisation with cholera toxin (CT) can target immunity to the genital tract, but has the potential to cause neurological side effects. CTA1-DD is a non-toxic potent mucosal adjuvant which combines the enzymatic properties of CT, with a B cell targeting moiety. Here, we demonstrate that intranasal immunisation with CTA1-DD and chlamydial Major Outer Membrane Protein (MOMP) results in the induction of neutralising systemic and mucosal antibodies, and reduces the level of chlamydial shedding following intravaginal challenge with Chlamydia muridarum. Thus, CTA1-DD is an effective adjuvant for vaccine development against Chlamydia trachomatis, and possibly also a range of other genital pathogens.

Long term immunity to live attenuated Japanese encephalitis chimeric virus vaccine : randomized, double-blind, 5-year phase II study in healthy adults.

In a randomized, double-blind study, 202 healthy adults were randomized to receive a live, attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) and placebo 28 days apart in a cross-over design. A subgroup of 98 volunteers received a JE-CV booster at month 6. Safety, immunogenicity, and persistence of antibodies to month 60 were evaluated. There were no unexpected adverse events (AEs) and the incidence of AEs between JE-CV and placebo were similar. There were three serious adverse events (SAE) and no deaths. A moderately severe case of acute viral illness commencing 39 days after placebo administration was the only SAE considered possibly related to immunization. 99% of vaccine recipients achieved a seroprotective antibody titer ≥ 10 to JE-CV 28 days following the single dose of JE-CV, and 97% were seroprotected at month 6. Kaplan Meier analysis showed that after a single dose of JE-CV, 87% of the participants who were seroprotected at month 6 were still protected at month 60. This rate was 96% among those who received a booster immunization at month 6. 95% of subjects developed a neutralizing titer ≥ 10 against at least three of the four strains of a panel of wild-type Japanese encephalitis virus (JEV) strains on day 28 after immunization. At month 60, that proportion was 65% for participants who received a single dose of JE-CV and 75% for the booster group. These results suggest that JE-CV is safe, well tolerated and that a single dose provides long-lasting immunity to wild-type strains

Induction of anti-chlamydial mucosal immunity by transcutaneous immunization is enhanced by topical application of GM-CSF

Transcutaneous immunization (TCI) involves the direct application of antigen plus adjuvant to skin, taking advantage of the large numbers of Langerhans cells and other resident skin dendritic cells, that process antigen then migrate to draining lymph nodes where immune responses are initiated. We have used this form of immunization to protect mice against genital tract and respiratory tract chlamydial infection. Protection was associated with local antibody responses in the vagina, uterus and lung as well as strong Th1 responses in the lymph nodes draining the reproductive tract and lungs respectively. In this study we show that topical application of GM-CSF to skin enhances the numbers and activation status of epidermal dendritic cells. Topical application of GM-CSF also increased the immune responses elicited by TCI. GM-CSF supplementation greatly increased cytokine (IFNgamma and IL-4) gene expression in lymph node and splenic cells compared to cells from animals immunized without GM-CSF. IgG responses in serum, uterine lavage and bronchoalveolar lavage and IgA responses in vaginal lavage were also increased by topical application of GM-CSF. The studies show that TCI induces protection against genital and respiratory tract chlamydial infections and that topical application of cytokines such as GM-CSF can enhance TCI-induced antibody and cell-mediated immunity.

Comparison of intranasal and transcutaneous immunization for induction of protective immunity against chlamydia muridarum respiratory tract infection

Chlamydia pneumoniae causes a range of respiratory infections including bronchitis, pharyngitis and pneumonia. Infection has also been implicated in exacerbation/initiation of asthma and chronic obstructive pulmonary disease (COPD) and may play a role in atherosclerosis and Alzheimer's disease. We have used a mouse model of Chlamydia respiratory infection to determine the effectiveness of intranasal (IN) and transcutaneous immunization (TCI) to prevent Chlamydia lung infection. Female BALB/c mice were immunized with chlamydial major outer membrane protein (MOMP) mixed with cholera toxin and CpG oligodeoxynucleotide adjuvants by either the IN or TCI routes. Serum and bronchoalveolar lavage (BAL) were collected for antibody analysis. Mononuclear cells from lung-draining lymph nodes were stimulated in vitro with MOMP and cytokine mRNA production determined by real time PCR. Animals were challenged with live Chlamydia and weighed daily following challenge. At day 10 (the peak of infection) animals were sacrificed and the numbers of recoverable Chlamydia in lungs determined by real time PCR. MOMP-specific antibody-secreting cells in lung tissues were also determined at day 10 post-infection. Both IN and TCI protected animals against weight loss compared to non-immunized controls with both immunized groups gaining weight by day 10-post challenge while controls had lost 6% of body weight. Both immunization protocols induced MOMP-specific IgG in serum and BAL while only IN immunization induced MOMP-specific IgA in BAL. Both immunization routes resulted in high numbers of MOMP-specific antibody-secreting cells in lung tissues (IN > TCI). Following in vitro re-stimulation of lung-draining lymph node cells with MOMP; IFNγ mRNA increased 20-fold in cells from IN immunized animals (compared to non-immunized controls) while IFNγ levels increased 6- to 7-fold in TCI animals. Ten days post challenge non-immunized animals had >7000 IFU in their lungs, IN immunized animals <50 IFU and TCI immunized animals <1500 IFU. Thus, both intranasal and transcutaneous immunization protected mice against respiratory challenge with Chlamydia. The best protection was obtained following IN immunization and correlated with IFNγ production by mononuclear cells in lung-draining LN and MOMP-specific IgA in BAL.

Innate Immunity in Lobsters: Partial Purification and Characterization of a Panulirus cygnus Anti-A Lectin

A lectin detected in haemolymph from the Australian spiny lobster Panulirus cygnus agglutinated human ABO Group A cells to a higher titre than Group O or B. The lectin also agglutinated rat and sheep erythrocytes, with reactivity with rat erythrocytes strongly enhanced by treatment with the proteolytic enzyme papain, an observation consistent with reactivity via a glycolipid. The lectin, purified by affinity chromatography on fixed rat-erythrocyte stroma, was inhibited equally by N-acetylglucosamine and N-acetylgalactosamine. Comparison of data from gel filtration of haemolymph (behaving as a 1,800,000 Da macromolecule), and polyacrylamide gel electrophoresis of purified lectin (a single 67,000 Da band), suggested that in haemolymph the lecin was a multimer. The purified anti-A lectin autoprecipitated unless the storage solution contained chaotropic inhibitors (125 mmol/L sucrose: 500 mmol/L urea). The properties of this anti-A lectin and other similar lectins are consistent with a role in innate immunity in these invertebrates.

SNAREing immunity : the role of SNAREs in the immune system

The trafficking of molecules and membranes within cells is a prerequisite for all aspects of cellular immune functions, including the delivery and recycling of cell surface proteins, secretion of immune mediators, ingestion of pathogens and activation of lymphocytes. SNARE (soluble-N-ethylmaleimide-sensitive-factor accessory-protein receptor)-family members mediate membrane fusion during all steps of trafficking, and function in almost all aspects of innate and adaptive immune responses. Here, we provide an overview of the roles of SNAREs in immune cells, offering insight into one level at which precision and tight regulation are instilled on immune responses.

Vaccination of healthy and diseased koalas (Phascolarctos cinereus) with a Chlamydia pecorum multi-subunit vaccine : evaluation of immunity and pathology

Chlamydial infections represent a major threat to the long-term survival of the koala and a successful vaccine would provide a valuable management tool. Vaccination however has the potential to enhance inflammatory disease in animals exposed to a natural infection prior to vaccination, a finding in early human and primate trials of whole cell vaccines to prevent trachoma. In the present study, we vaccinated both healthy koalas as well as clinically diseased koalas with a multi-subunit vaccine consisting of Chlamydia pecorum MOMP and NrdB mixed with immune stimulating complex as adjuvant. Following vaccination, there was no increase in inflammatory pathological changes in animals previously infected with Chlamydia. Strong antibody (including neutralizing antibodies) and lymphocyte proliferation responses were recorded in all vaccinated koalas, both healthy and clinically diseased. Vaccine induced antibodies specific for both vaccine antigens were observed not only in plasma but also in ocular secretions. Our data shows that an experimental chlamydial vaccine is safe to use in previously infected koalas, in that it does not worsen infection-associated lesions. Furthermore, the prototype vaccine is effective, as demonstrated by strong levels of neutralizing antibody and lymphocyte proliferation responses in both healthy and clinically diseased koalas. Collectively, this work illustrates the feasibility of developing a safe and effective Chlamydia vaccine as a tool for management of disease in wild koalas.

Probiotics, immunity and exercise : a review

Nutritional practices that promote good health and optimal athletic performance are of interest to athletes, coaches, exercise scientists and dietitians. Probiotic supplements modulate the intestinal microbial flora and offer promise as a practical means of enhancing gut and immune function. The intestinal microbial flora consists of diverse bacterial species that inhabit the gastrointestinal tract. These bacteria are integral to the ontogeny and regulation of the immune system, protection of the body from injection, and maintenance of intestinal homeostasis. The interaction of the gut microbial flora with intestinal epithelial cells and immune cells exerts beneficial effects on the upper respiratory tract, skin and uro-genital tract. The capacity for probiotics to modulate perturbations in immune function after exercise highlight their potential for use in individuals exposed to high degrees of physical and environment stress. Future studies are required to address issues of dose-response in various exercise settings, the magnitude of species-specific effects, mechanisms of action and clinical outcomes in terms of health and performance.

A single copy of a virus-derived transgene encoding hairpin RNA gives immunity to barley yellow dwarf virus

Barley yellow dwarf virus-PAV (BYDV-PAV) is the most serious and widespread virus of cereals worldwide. Natural resistance genes against this luteovirus give inadequate control, and previous attempts to introduce synthetic resistance into cereals have produced variable results. In an attempt to generate barley with protection against BYDV-PAV, plants were transformed with a transgene designed to produce hairpin (hp)RNA containing BYDV-PAV sequences. From 25 independent barley lines transformed with the BYDV-PAV hpRNA construct, nine lines showed extreme resistance to the virus and the majority of these contained a single transgene. In the progeny of two independent transgenic lines, inheritance of a single transgene consistently correlated with protection against BYDV-PAV. This protection was rated as immunity because the virus could not be detected in the challenged plants by ELISA nor recovered by aphid feeding experiments. In the field, BYDV-PAV is sometimes associated with the related luteovirus Cereal yellow dwarf virus-RPV (CYDV-RPV). When the transgenic plants were challenged with BYDV-PAV and CYDV-RPV together, the plants were susceptible to CYDV-RPV but immune to BYDV-PAV. This shows that the immunity is virus-specific and not broken down by the presence of CYDV. It suggests that CYDV-RPV does not encode a silencing-suppressor gene or that its product does not protect BYDV-PAV against the plant's RNAi-like defence mechanism. Either way, our results indicate that the BYDV-PAV immunity will be robust in the field and is potentially useful in minimizing losses in cereal production worldwide.

Innate and adaptive immunity at mucosal surfaces of the female reproductive tract : stratification and integration of immune protection against the transmission of sexually transmitted infections

This review examines the multiple levels of pre-existing immunity in the upper and lower female reproductive tract. In addition, we highlight the need for further research of innate and adaptive immune protection of mucosal surfaces in the female reproductive tract. Innate mechanisms include the mucus lining, a tight epithelial barrier and the secretion of antimicrobial peptides and cytokines by epithelial and innate immune cells. Stimulation of the innate immune system also serves to bridge the adaptive arm resulting in the generation of pathogen-specific humoral and cell-mediated immunity. Less understood are the multiple components that act in a coordinated way to provide a network of ongoing protection. Innate and adaptive immunity in the human female reproductive tract are influenced by the stage of menstrual cycle and are directly regulated by the sex steroid hormones, progesterone and estradiol. Furthermore, the effect of hormones on immunity is mediated both directly on immune and epithelial cells and indirectly by stimulating growth factor secretion from stromal cells. The goal of this review is to focus on the diverse aspects of the innate and adaptive immune systems that contribute to a unique network of protection throughout the female reproductive tract.

Sex hormone regulation of innate immunity in the female reproductive tract : the role of epithelial cells in balancing reproductive potential with protection against sexually transmitted pathogens

The immune system in the female reproductive tract (FRT) does not mount an attack against HIV or other sexually transmitted infections (STI) with a single endogenously produced microbicide or with a single arm of the immune system. Instead, the body deploys dozens of innate antimicrobials to the secretions of the female reproductive tract. Working together, these antimicrobials along with mucosal antibodies attack many different viral, bacterial and fungal targets. Within the FRT, the unique challenges of protection against sexually transmitted pathogens coupled with the need to sustain the development of an allogeneic fetus have evolved in such a way that sex hormones precisely regulate immune function to accomplish both tasks. The studies presented in this review demonstrate that estradiol and progesterone secreted during the menstrual cycle act both directly and indirectly on epithelial cells and other immune cells in the reproductive tract to modify immune function in a way that is unique to specific sites throughout the FRT. As presented in this review, studies from our laboratory and others demonstrate that the innate immune response is under hormonal control, varies with the stage of the menstrual cycle, and as such is suppressed at mid-cycle to optimize conditions for successful fertilization and pregnancy. In doing so, a window of STI vulnerability is created during which potential pathogens including HIV enter the reproductive tract to infect host targets.