Brucella outer membrane complex-loaded microparticles as a vaccine against Brucella ovis in rams

Rev1Δwzm vaccine candidate is safe in young and adult sheep and protects against Brucella ovis infection in rams

Small ruminants affected by brucellosis, caused mainly by Brucella melitensis and B. ovis, suffer reproductive disorders, leading to significant economic losses worldwide. Vaccination is an essential tool to prevent the disease in ovine and caprine livestock, but the only vaccine recommended to date is B. melitensis Rev1, which in sheep is only safe for use in lambs aged 3-4 months. This restriction poses considerable practical challenges for the implementation of Rev1 in countries with endemic brucellosis and/or limited resources, where there is a need for mass vaccination with a safe vaccine to control the disease in both animals and humans. We recently developed a B. melitensis strain Rev1Δwzm showing superior vaccine properties in mice and safety in pregnant ewes. Here, we report that Rev1Δwzm (i) is safe in young and adult sheep, both male and female; (ii) induces a transient serological response in the Rose Bengal test in ≤50 % of sheep, confirmed to some extent by the complement fixation test, and a stronger, more persistent anti- rough-LPS response; and (iii) protects rams against a B. ovis challenge 25 weeks after vaccination. To resolve the problem of serological interference, the use of green fluorescent protein tagging strategy allowed us to identify vaccinated sheep with only a single inoculation. These results, together with the previously reported safety in pregnant ewes, position Rev1Δwzm as a firm vaccine candidate and a promising alternative to Rev1. Further experiments are warranted to assess its efficacy against B. melitensis in pregnant ewes.

A Brucella melitensis H38ΔwbkF rough mutant protects against Brucella ovis in rams

Brucella melitensis and Brucella ovis are gram-negative pathogens of sheep that cause severe economic losses and, although B. ovis is non-zoonotic, B. melitensis is the main cause of human brucellosis. B. melitensis carries a smooth (S) lipopolysaccharide (LPS) with an N-formyl-perosamine O-polysaccharide (O-PS) that is absent in the rough LPS of B. ovis. Their control and eradication require vaccination, but B. melitensis Rev 1, the only vaccine available, triggers anti-O-PS antibodies that interfere in the S-brucellae serodiagnosis. Since eradication and serological surveillance of the zoonotic species are priorities, Rev 1 is banned once B. melitensis is eradicated or where it never existed, hampering B. ovis control and eradication. To develop a B. ovis specific vaccine, we investigated three Brucella live vaccine candidates lacking N-formyl-perosamine O-PS: Bov::CAΔwadB (CO2-independent B. ovis with truncated LPS core oligosaccharide); Rev1::wbdRΔwbkC (carrying N-acetylated O-PS); and H38ΔwbkF (B. melitensis rough mutant with intact LPS core). After confirming their attenuation and protection against B. ovis in mice, were tested in rams for efficacy. H38ΔwbkF yielded similar protection to Rev 1 against B. ovis but Bov::CAΔwadB and Rev1::wbdRΔwbkC conferred no or poor protection, respectively. All H38ΔwbkF vaccinated rams developed a protracted antibody response in ELISA and immunoprecipitation B. ovis diagnostic tests. In contrast, all remained negative in Rose Bengal and complement fixation tests used routinely for B. melitensis diagnosis, though some became positive in S-LPS ELISA owing to LPS core epitope reactivity. Thus, H38ΔwbkF is an interesting candidate for the immunoprophylaxis of B. ovis in B. melitensis-free areas.

Polymeric antigen BLSOmp31 formulated with class B CpG-ODN in a nanostructure (BLSOmp31/CpG-ODN/Coa-ASC16) administered by parenteral or mucosal routes confers protection against Brucella ovis in Balb/c mice

Previously, we demonstrated that the chimera BLSOmp31 formulated in chitosan microspheres or Poloxamer407-Chitosan administered via the nasal and the ocular mucosa conferred partial protection in sheep against B. ovis. In this work, we tested a new delivery system for mucosal immunization with BLSOmp31 in the murine model to improve the efficacy of previously used formulations. First, we evaluated the protective efficacy against B. ovis induced by BLSOmp31 administered by the subcutaneous route using either BLSOmp31 alone, co-administered with immunostimulatory synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG-ODN) or with CpG-ODN in a nanostructure called Coa-ASC16 compared with BLSOmp31 emulsified in Incomplete Freund Adjuvant. Then, we evaluated the protection conferred by the best performing formulation (BLSOmp31/CpG-ODN/Coa-ASC16) administered by both subcutaneous and ocular routes. BLSOmp31/CpG-ODN/Coa-ASC16 injected subcutaneously did not induce higher IgG antibody levels compared to BLSOmp31 alone or BLSOmp31/CpG-ODN but it did stimulate a mixed immune Th1-Th2 response with the highest levels of IFN-ɣ and conferred significant protection against the B. ovis challenge. Although ocular instillation of BLSOmp31/CpG-ODN/Coa-ASC16 showed a similar degree of protection compared to the parenteral route (3.66 and 3.60 logs of protection, respectively), it induced lower levels in serum of specific IgG (with mixed IgG1/IgG2a) and IgA antibodies and, less IFN-ɣ and IL-4 than the subcutaneous route. No antibodies were detected in vaginal lavages or saliva. Fecal antigen-specific IgA was slightly higher in mice immunized with BLSOmp31/CpG-ODN/Coa-ASC16 subcutaneously compared with the ocular route. These results indicate that BLSOmp31/CpG-ODN/Coa-ASC16 was a safe and effective vaccine against B. ovis in mice.

Mucosal immunization with polymeric antigen BLSOmp31 using alternative delivery systems against Brucella ovis in rams

Subcellular vaccines against ovine contagious epididymitis due Brucella ovis can solve some shortcomings associated with the use of Brucella melitensis Rev 1. We have demonstrated that the parenteral immunization with polymeric antigen BLSOmp31 emulsified in oil adjuvant conferred significant protection against B. ovis in rams. In our previous studies, we have characterized chitosan microspheres (ChMs) and a thermoresponsive and mucoadhesive in situ gel (Poloxamer 407-Ch) as two novel formulation strategies for the delivery of BLSOmp31 in nasal as well as conjunctival mucosa. In the present work, we evaluated the immunogenicity and protection conferred by the intranasal and conjunctival immunization with these two mucosal delivery systems against B. ovis in rams. BLSOmp31-ChM administered by intranasal route and BLSOmp31-P407-Ch applied by intranasal or conjunctival routes induced systemic, local and preputial IgG and IgA antibody response. Neither formulation showed interference in the serological diagnosis. Thus, mucosal immunization using either formulation induced significant specific cellular immune responses (in vitro and in vivo) and it prevented the excretion of B. ovis in semen. Although these vaccines did not prevent infection in immunized rams, colonization reduction of infected organs and bacterial distribution differed significantly between vaccinated and unvaccinated rams.

Comparison of Four Human Papillomavirus Genotyping Methods: Next-generation Sequencing, INNO-LiPA, Electrochemical DNA Chip, and Nested-PCR

Background

Human papillomavirus (HPV) infection causes cervical cancer, thus necessitating early detection by screening. Rapid and accurate HPV genotyping is crucial both for the assessment of patients with HPV infection and for surveillance studies.

Methods

Fifty-eight cervicovaginal samples were tested for HPV genotypes using four methods in parallel: nested-PCR followed by conventional sequencing, INNO-LiPA, electrochemical DNA chip, and next-generation sequencing (NGS).

Results

Seven HPV genotypes (16, 18, 31, 33, 45, 56, and 58) were identified by all four methods. Nineteen HPV genotypes were detected by NGS, but not by nested-PCR, INNO-LiPA, or electrochemical DNA chip.

Conclusions

Although NGS is relatively expensive and complex, it may serve as a sensitive HPV genotyping method. Because of its highly sensitive detection of multiple HPV genotypes, NGS may serve as an alternative for diagnostic HPV genotyping in certain situations.

Scaffold protein FHL2 facilitates MDM2-mediated degradation of IER3 to regulate proliferation of cervical cancer cells

The expression of immediate early response 3 (IER3), a protein with a short half-life, is rapidly induced by various cellular stimuli. We recently reported that IER3 induces the apoptosis of cervical cancer cells and that its expression is downregulated in patients with cervical cancer. However, the molecular mechanism involved in the rapid degradation of IER3 remains unknown. Here, we demonstrate that MDM2 is an E3 ligase that interacts with IER3 and promotes its ubiquitination, followed by proteasomal degradation. Polyubiquitination of the conserved lysine 60 of IER3 is essential for its degradation. In addition, four and a half LIM domains protein 2 (FHL2) binds to both IER3 and MDM2, allowing for efficient MDM2-mediated IER3 degradation by facilitating an association between MDM2 and IER3. Moreover, IER3 induces cell cycle arrest in cervical cancer cells and its activity is further enhanced in cells in which FHL2 or MDM2 was silenced, thereby preventing IER3 degradation. The E6 and E7 oncoproteins of human papilloma virus 18 regulated IER3 expression. FHL2 expression was significantly higher in the squamous epithelium of cervical carcinoma tissues than in non-cancerous cervical tissues, whereas cervical carcinoma expression of IER3 was downregulated in this region. Thus, we determined the molecular mechanism responsible for IER3 degradation, involving a ternary complex of IER3, MDM2 and FHL2, which may contribute to cervical tumor growth. Furthermore, we demonstrated that FHL2 serves as a scaffold for E3 ligase and its substrate during the ubiquitination reaction, a function that has not been previously reported for this protein.

The potential of plants for the production and delivery of human papillomavirus vaccines

The available vaccines against human papillomavirus have some limitations such as low coverage due to their high cost, reduced immune coverage and the lack of therapeutic effects. Recombinant vaccines produced in plants (genetically engineered using stable or transient expression systems) offer the possibility to obtain low cost, efficacious and easy to administer vaccines. The status on the development of plant-based vaccines against human papillomavirus is analyzed and placed in perspective in this review. Some candidates have been characterized at a preclinical level with interesting outcomes. However, there is a need to perform the immunological characterization of several vaccine prototypes, especially through the oral administration route, as well as develop new candidates based on new chimeric designs intended to provide broader immunoprotection and therapeutic activity.

IER3 is a crucial mediator of TAp73β-induced apoptosis in cervical cancer and confers etoposide sensitivity

Infection with high-risk human papillomaviruses (HPVs) causes cervical cancer. E6 oncoprotein, an HPV gene product, inactivates the major gatekeeper p53. In contrast, its isoform, TAp73β, has become increasingly important, as it is resistant to E6. However, the intracellular signaling mechanisms that account for TAp73β tumor suppressor activity in cervix are poorly understood. Here, we identified that IER3 is a novel target gene of TAp73β. In particular, TAp73β exclusively transactivated IER3 in cervical cancer cells, whereas p53 and TAp63 failed to do. IER3 efficiently induced apoptosis, and its knockdown promoted survival of HeLa cells. In addition, TAp73β-induced cell death, but not p53-induced cell death, was inhibited upon IER3 silencing. Moreover, etoposide, a DNA-damaging chemotherapeutics, upregulated TAp73β and IER3 in a c-Abl tyrosine kinase-dependent manner, and the etoposide chemosensitivity of HeLa cells was largely determined by TAp73β-induced IER3. Of interest, cervical carcinomas from patients express no observable levels of two proteins. Thus, our findings suggest that IER3 is a putative tumor suppressor in the cervix, and the c-Ab1/p73β/IER3 axis is a novel and crucial signaling pathway that confers etoposide chemosensitivity. Therefore, TAp73β and IER3 induction would be a valuable checkpoint for successful therapeutic intervention of cervical carcinoma patients.

Evaluation of ZAR1 and SFRP4 methylation status as potentials biomarkers for diagnosis in cervical cancer: exploratory study phase I

CONTEXT

Aberrant hypermethylation of promoter region of tumor suppressor genes could be used as cancer biomarkers.

OBJECTIVE

To test methylation status of ZAR1 and SFRP4 promoter regions as potentials biomarkers for diagnosis of preneoplastic and neoplastic lesions of cervix.

MATERIALS AND METHODS

Cytobrush samples were evaluated by Methylation specific PCR (MSP) and quantitative MSP (qMSP).

RESULTS

ZAR1 and SFRP4 methylation frequency increased as the grade of lesion increased and the differences between normal and cervical cancer (CC) are statistically significant (p < 0.0001). qMSP showed higher ZAR1 and SFRP4 methylation levels in cancer than normal epithelia (p < 0.001) and preneoplastics lesions (p < 0.01).

DISCUSSION

qMSP quantify methylation levels and have high sensitivity and specificity.

CONCLUSION

ZAR1 and SFRP4 qMSP could be used as potential biomarker for CC diagnosis.

Immunization with Brucella VirB proteins reduces organ colonization in mice through a Th1-type immune response and elicits a similar immune response in dogs

VirB proteins from Brucella spp. constitute the type IV secretion system, a key virulence factor mediating the intracellular survival of these bacteria. Here, we assessed whether a Th1-type immune response against VirB proteins may protect mice from Brucella infection and whether this response can be induced in the dog, a natural host for Brucella. Splenocytes from mice immunized with VirB7 or VirB9 responded to their respective antigens with significant and specific production of gamma interferon (IFN-γ), whereas interleukin-4 (IL-4) was not detected. Thirty days after an intraperitoneal challenge with live Brucella abortus, the spleen load of bacteria was almost 1 log lower in mice immunized with VirB proteins than in unvaccinated animals. As colonization reduction seemed to correlate with a Th1-type immune response against VirB proteins, we decided to assess whether such a response could be elicited in the dog. Peripheral blood mononuclear cells (PBMCs) from dogs immunized with VirB proteins (three subcutaneous doses in QuilA adjuvant) produced significantly higher levels of IFN-γ than cells from control animals upon in vitro stimulation with VirB proteins. A skin test to assess specific delayed-type hypersensitivity was positive in 4 out of 5 dogs immunized with either VirB7 or VirB9. As both proteins are predicted to locate in the outer membrane of Brucella organisms, the ability of anti-VirB antibodies to mediate complement-dependent bacteriolysis of B. canis was assessed in vitro. Sera from dogs immunized with either VirB7 or VirB9, but not from those receiving phosphate-buffered saline (PBS), produced significant bacteriolysis. These results suggest that VirB-specific responses that reduce organ colonization by Brucella in mice can be also elicited in dogs.

Vaccination against oncogenic human papillomavirus infection in HIV-infected populations: review of current status and future perspectives

Background Men and women with HIV infection are at increased risk of developing cancers associated with human papillomavirus (HPV). The two licensed prophylactic HPV vaccines protect against de novo infection with HPV-16 and HPV-18, which cause the majority of HPV-associated cancers. Currently, no vaccine efficacy data are available for persons with HIV infection. Nevertheless, some countries have implemented specific HPV vaccination recommendations for HIV-positive populations. To specifically recommend prophylactic HPV vaccination in people with HIV, the vaccines must be safe and immunogenic in immunosuppressed people at a high risk of HPV infection. This review aims to summarise the current knowledge from published HPV vaccine trials in HIV-infected populations, to compile scheduled and ongoing HPV vaccine trials with HIV-positive study populations and to extrapolate the relevant knowledge about HPV vaccine efficacy in HIV-negative populations to an HIV context.

METHODS

The databases PubMed, Scopus and ClinicalTrials.gov were searched for peer-reviewed articles and scheduled or ongoing clinical HPV vaccine trials enrolling HIV-positive persons.

RESULTS

Current data indicate that prophylactic HPV vaccines are safe and immunogenic in different HIV-positive populations (children, female adolescents, adults). Increased immunogenicity has been reported in persons on antiretroviral therapy compared with antiretroviral-naïve persons, whereas no clear association has been found between CD4(+) cell count at immunisation and vaccine response. Several scheduled and ongoing HPV vaccine trials aim to determine vaccine efficacy against disease endpoints in HIV-infected study populations.

CONCLUSION

Prophylactic HPV vaccination appears safe, immunogenic and, by extrapolation, likely to reduce HPV-associated cancer development among persons with HIV infection.

Brucella ovis lacking a species-specific putative ATP-binding cassette transporter is attenuated but immunogenic in rams

Ovine brucellosis caused by Brucella ovis is considered one of the most important reproductive diseases of rams worldwide. This study aimed to characterize the kinetics of infection of a ΔabcAB B. ovis mutant strain in rams. Twelve 1-year-old crossbred rams were used. Six rams were challenged with 2 mL of a suspension containing 1.2×10(9) CFU/mL of B. ovis strain ATCC25840 (wild type) by intraprepucial inoculation and additional 50 μL in each conjunctival sac of a suspension containing 1.2×10(10) CFU/mL of the same strain. The other six rams were challenged with an equivalent number of CFU of the mutant strain ΔabcAB B. ovis through the same routes. Serum samples for serology and semen and urine samples for bacteriologic culture and PCR were collected weekly during 24 weeks. At 24 weeks post infection, tissue samples were collected for bacteriologic culture and PCR. All rams inoculated with wild type or the ΔabcAB strain seroconverted at the fourth week post infection, remaining positive up to the 16th week post infection. PCR and bacteriology demonstrated that only rams inoculated with the wild type strain shed the organism in semen and urine. Lymphocytes from rams inoculated with wild type or ΔabcAB B. ovis had significantly higher proliferation in response to B. ovis antigens when compared with unstimulated controls. Tissue bacteriology and PCR detected B. ovis in all rams challenged with the wild type strain, whereas only one ΔabcAB-infected ram had a positive iliac lymph node sample by PCR.

Host-Brucella interactions and the Brucella genome as tools for subunit antigen discovery and immunization against brucellosis

Vaccination is the most important approach to counteract infectious diseases. Thus, the development of new and improved vaccines for existing, emerging, and re-emerging diseases is an area of great interest to the scientific community and general public. Traditional approaches to subunit antigen discovery and vaccine development lack consideration for the critical aspects of public safety and activation of relevant protective host immunity. The availability of genomic sequences for pathogenic Brucella spp. and their hosts have led to development of systems-wide analytical tools that have provided a better understanding of host and pathogen physiology while also beginning to unravel the intricacies at the host-pathogen interface. Advances in pathogen biology, host immunology, and host-agent interactions have the potential to serve as a platform for the design and implementation of better-targeted antigen discovery approaches. With emphasis on Brucella spp., we probe the biological aspects of host and pathogen that merit consideration in the targeted design of subunit antigen discovery and vaccine development.

Effects of a narrative HPV vaccination intervention aimed at reaching college women: a randomized controlled trial

This longitudinal study reports on the development and evaluation of a narrative intervention aimed at increasing human papillomavirus (HPV) vaccination among college women. The prevention of HPV is a public health priority due to its pervasiveness and relationship to cervical cancer, the second leading cause of cancer deaths among women worldwide. Pilot work utilizing culture-centric narrative theory guided development of the intervention content. Exemplification theory led to hypotheses comparing communication sources of the narrative messages (peer only, medical expert only, or a combination of the two source types) in a four-arm randomized controlled trial (N = 404; 18-26 year olds). The combined peer-expert narrative intervention nearly doubled vaccination compared to controls (22% vs. 12%). The pragmatic goal of increasing HPV vaccination and the theoretical predictions about message source were supported. As predicted, the inclusion of peer and medical expert sources plays a critical role in promoting HPV vaccination among college women. Furthermore, the intervention increased HPV vaccination by increasing vaccine self-efficacy and intent. Theoretical and practical implications for designing effective HPV vaccine messages are discussed.

Acellular vaccines for ovine brucellosis: a safer alternative against a worldwide disease

Ovine brucellosis is a very contagious zoonotic disease distributed worldwide and constitutes a very important zoosanitary and economic problem. The control of the disease includes animal vaccination and slaughter of infected flocks. However, the commercially available vaccine in most countries is based on the attenuated strain Brucella melitensis Rev 1, which presents important safety drawbacks. This review is focused on the most recent and promising acellular vaccine proposals.

Nuclear expression of Rac1 in cervical premalignant lesions and cervical cancer cells

Background

Abnormal expression of Rho-GTPases has been reported in several human cancers. However, the expression of these proteins in cervical cancer has been poorly investigated. In this study we analyzed the expression of the GTPases Rac1, RhoA, Cdc42, and the Rho-GEFs, Tiam1 and beta-Pix, in cervical pre-malignant lesions and cervical cancer cell lines.

Methods

Protein expression was analyzed by immunochemistry on 102 cervical paraffin-embedded biopsies: 20 without Squamous Intraepithelial Lesions (SIL), 51 Low- grade SIL, and 31 High-grade SIL; and in cervical cancer cell lines C33A and SiHa, and non-tumorigenic HaCat cells. Nuclear localization of Rac1 in HaCat, C33A and SiHa cells was assessed by cellular fractionation and Western blotting, in the presence or not of a chemical Rac1 inhibitor (NSC23766).

Results

Immunoreacivity for Rac1, RhoA, Tiam1 and beta-Pix was stronger in L-SIL and H-SIL, compared to samples without SIL, and it was significantly associated with the histological diagnosis. Nuclear expression of Rac1 was observed in 52.9% L-SIL and 48.4% H-SIL, but not in samples without SIL. Rac1 was found in the nucleus of C33A and SiHa cells but not in HaCat cells. Chemical inhibition of Rac1 resulted in reduced cell proliferation in HaCat, C33A and SiHa cells.

Conclusion

Rac1 is expressed in the nucleus of epithelial cells in SILs and cervical cancer cell lines, and chemical inhibition of Rac1 reduces cellular proliferation. Further studies are needed to better understand the role of Rho-GTPases in cervical cancer progression.

Small molecule inhibitors of the HPV16-E6 interaction with caspase 8

High-risk strains of human papillomaviruses (HPVs) cause nearly all cases of cervical cancer as well as a growing number of head and neck cancers. The oncogenicity of these viruses can be attributed to the activities of their two primary oncoproteins, E6 and E7. The E6 protein has among its functions the ability to prevent apoptosis of infected cells through its binding to FADD and caspase 8. A small molecule library was screened for candidates that could inhibit E6 binding to FADD and caspase 8. Flavonols were found to possess this activity with the rank order of myricetin>morin>quercetin>kaempferol=galangin≫(apigenin, 7-hydroxyflavonol, rhamnetin, isorhamnetin, geraldol, datiscetin, fisetin, 6-hydroxyflavonol). Counter screening, where the ability of these chosen flavonols to inhibit caspase 8 binding to itself was assessed, demonstrated that myricetin, morin and quercetin inhibited GST-E6 and His-caspase 8 binding in a specific manner. The structure-activity relationships suggested by these data are unique and do not match prior reports on flavonols in the literature for a variety of anticancer assays.

Smoking habit, immune suppression, oral contraceptive use, and hormone replacement therapy use and cervical carcinogenesis: a review of the literature

High-risk human papillomaviruses (HPVs) are involved in the etiopathogenesis of cervical intraepithelial neoplasia (CIN) and cervical cancer. After taking HPV into account, smoking habit appears to be the most significant environmental risk factor, and the risk of this malignancy increases significantly with intensity and duration of smoking. Women with human immunodeficiency virus (HIV) infection experience a higher incidence of CIN and invasive cervical cancer. Among HIV+ women, the highly active antiretroviral therapy increases the regression rate of CIN, but the majority of these lesions do not regress to normal. As far as oral contraceptives (OCs), a systematic review of 28 studies found that, compared with never pill users, the relative risk (RR) of cervical cancer increased with increasing duration of OC use. The results were similar for squamous cell carcinoma and adenocarcinoma, and the RRs decreased after pill discontinuation. However, by weighing risks and benefits, the World Health Organization does not recommend any change in OC practice. There is no correlation between hormone replacement therapy and cervical cancer. Experimental data have shown that estradiol and progesterone can modulate the host immune response to HPV16. Prophylactic vaccination in conjunction with cervical screening is the best prevention strategy for cervical cancer.

Human papillomavirus vaccines: new tools for accelerating cervical cancer prevention in developing countries

Despite the available knowledge and tools to prevent cervical cancer, it remains the second most common cancer in women, with four-fifths of the cases occurring in developing countries. Projections are for a 90% increase in global cervical cancer cases by 2020 if no additional public-health interventions are implemented. Prophylactic human papillomavirus (HPV) vaccines, which have proven immunogenicity, safety and efficacy, are now commercially available; and coupled together with quality screening have the potential to dramatically accelerate reductions in cervical cancer mortality rates and save millions of women's lives. The current cost of the new HPV vaccines and new screening technologies, however, are a major barrier to their widespread implementation. There is an urgent need for HPV vaccines and new technologies for effective screening to become more available and affordable, especially to poor communities everywhere.

Protection of mice against Brucella abortus 544 challenge by vaccination with recombinant OMP28 adjuvanted with CpG oligonucleotides

Brucella abortus, a gram negative, facultative intracellular pathogen causes brucellosis in many animal species and humans. Although live, attenuated vaccines are available against this infection, they suffer from certain limitations. Therefore, the development of an effective subunit vaccine against brucellosis is an area of intense research. The outer membrane proteins (OMPs) of Brucella species have been extensively studied for its immunogenicity and protective ability. We have investigated the potential of CpG ODN to enhance the immunogenicity and protective efficacy of recombinant 28 kDa outer membrane protein (rOMP28) of Brucella melitensis. The study demonstrated vigorous immunoglobulin G (IgG) response of OMP28. The administration of rOMP28 with CpG caused increased cell mediated immune response in terms of induced IgG2a, T-cell proliferation and up-regulation of type I cytokine expression. In contrast, the free antigen suppressed the interferon gamma (type I cytokine) production on in-vitro stimulation of spleenocytes. The result indicates the role of OMP28 in the down regulation of IFN-gamma production. Moreover, the B. abortus S-19 vaccinated mice showed highest production of IL-4 and IFN-gamma. The protective ability of the antigen was evaluated by systemic bacterial clearance after challenging the mouse with B. abortus 544 pathogen. The level of protection was significant in rOMP28+CpG treated mice but was lower than the required level. The results of the present study indicate that rOMP28 could be an immunogen capable of inducing both humoral and cellular immune response. The humoral response was biased towards Th1 type when it was co-administered with CpG.

Vaccine adjuvants: current challenges and future approaches

For humans, companion animals, and food producing animals, vaccination has been touted as the most successful medical intervention for the prevention of disease in the twentieth century. However, vaccination is not without problems. With the development of new and less reactogenic vaccine antigens, which take advantage of molecular recombinant technologies, also comes the need for more effective adjuvants that will facilitate the induction of adaptive immune responses. Furthermore, current vaccine adjuvants are successful at generating humoral or antibody mediated protection but many diseases currently plaguing humans and animals, such as tuberculosis and malaria, require cell mediated immunity for adequate protection. A comprehensive discussion is presented of current vaccine adjuvants, their effects on the induction of immune responses, and vaccine adjuvants that have shown promise in recent literature.

Efficacy of bp26 and bp26/omp31 B. melitensis Rev.1 deletion mutants against Brucella ovis in rams

Brucella melitensis Rev.1 is the most effective vaccine against B. ovis infection in sheep but induces antibodies interfering with B. melitensis diagnosis. Brucella BP26 and Omp31 proteins are differential diagnostic antigens. Single or double bp26 and omp31 Rev.1 deletion mutants have been proven effective against B. melitensis in sheep. Here, the CGV26 (deleted in bp26 gene) and CGV2631 (deleted in both bp26 and omp31 genes) mutants have been tested for efficacy against B. ovis in rams. Either inoculated subcutaneously or conjunctivally, both mutants conferred significant protection against B. ovis. The protection induced by CGV26 was similar to that of Rev.1 but significantly higher than that conferred by CGV2631. In conclusion, the CGV26 mutant, in association with the adequate diagnostic strategy, could be a useful alternative to Rev.1 for sheep vaccination against B. ovis infections in those countries performing simultaneously B. melitensis and B. ovis eradication campaigns.

Stability of poly(epsilon-caprolactone) microparticles containing Brucella ovis antigens as a vaccine delivery system against brucellosis

In previous works, our research group has successfully proved the use of subcellular vaccines based on poly(epsilon-caprolactone) (PEC) microparticles containing an antigenic extract of Brucella ovis (HS) against experimental brucellosis in both mice and rams. However, the successful exploitation of pharmaceutical products, and therefore of this product as veterinary vaccine, requires preservation of both biological activity and native structure in all steps of development from purification to storage. In this context, we have carried out an accelerated stability study to evaluate the relative stability of HS when loading in PEC microparticles. For this purpose, freeze-dried microparticles were stored at 40 +/- 1 degrees C and 75% RH as a preliminary analysis of a stability testing. The results showed that both physico-chemical (size, morphology, antigen content, release profile) and biological (integrity and antigenicity of the HS) properties were preserved after 6 months of storage. On the contrary, after 1 year of storage, the HS release profile was dramatically affected probably due to a progressive loss of the polymer microstructure. In addition, the degradation and loss of the antigenicity of the HS components was also evident by SDS-PAGE and immunoblotting analysis. In fact, after 12 months of storage, only the integrity and antigenicity of two of the major protective proteins of the HS antigenic complex were preserved.

Liposomised recombinant ribosomal L7/L12 protein protects BALB/c mice against Brucella abortus 544 infection

Brucella abortus, a facultative intracellular pathogen, is of tremendous zoonotic importance because of its ability to induce spontaneous abortion in cattle and other livestock. It is also known to cause persistent undulant fever, endocarditis, arthritis, osteomyelitis and meningitis in humans. The available vaccines against this dreadful infection suffer from limitations like short-term immunity, increased risk of hypersensitivity and low prophylactic index in the recipients. In the present study, we have demonstrated that liposomal form of a recombinant ribosomal L7/L12 protein, a B-T cell antigen of B. abortus, activates strong immune response in the host. In contrast, free antigen generates moderate immune response in the immunised animals. The liposomisation of rL7/L12 protein causes tremendous increase in cell-mediated immune response in terms of delayed type hypersensitivity, T-cell proliferation and up-regulation in type I cytokine expression, etc. Moreover, the liposome encapsulated antigen elicited stronger humoral immune response as compared to standard vaccine (S-19) or IFA-L7/L12 combination in the immunised animals. The effectiveness of liposome-based vaccine was also substantiated by better systemic clearance of bacterial load after challenging the animals with B. abortus 544 pathogen. The results of the present study suggest the potential of liposome-based rL7/L12 antigen as prospective and efficient candidate vaccine capable of eliciting both cell mediated as well as humoral immune responses against experimental murine brucellosis.