Serum Antibody Responses Research Articles

IL-17 Producing T cells as Predictors of Primary Immunodeficiencies in Patients with Candida Infections

Background: IL-17 producing T cells are a distinct subset of CD4+ T cells, which are recognized to have an essential role in protection against certain fungi and extracellular pathogens. Objectives: This study aims to evaluate the number of IL-17 producing T cells as a predictor of primary immunodeficiency disorders in patients with Candida infections and low numbers of IL-17 producing T cells. Methods: Seven newly diagnosed patients with documented Candida infections aged between 4 and 35 years were included in this study. Before establishing the diagnosis of chronic mucocutaneous candidiasis, a thorough immunodeficiency workup, including complete blood count, serum Ig levels and antibody responses, flow-cytometry evaluation, and LTT, was completed for all the patients, and other immunodeficiency disorders, including combined and phagocytic deficiencies, were ruled out. Then, IL-17 producing T cells were detected using antiCD3 and anti-IL-17 antibodies through flow-cytometry evaluation. Results: The IL-17 producing T cells significantly decreased in the peripheral blood of patients with PID and candida infections. A P-value of less than 0.05 was considered statistically significant. Conclusions: To conclude, in cases of recurrent candida infections, initial assessment of IL-17 producing T cells may act as a predictor of an underlying primary immunodeficiency. In patients with low counts of IL-17 producing T cells, selecting a targeted panel of genetic tests may become more helpful in the detection of certain immunodeficiency disorders than performing whole-exome sequence analysis.

Assessment of specific human antibodies against SARS-CoV-2 receptor binding domain by rapid in-house ELISA.

The recently emerged SARS-CoV-2 caused a global pandemic since the last two years. The urgent need to control the spread of the virus and rapid application of the suitable health measures raised the importance of available, rapid, and accurate diagnostic approaches. The purpose of this study is to describe a rapid in-house optimized ELISA based on the expression of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein in a prokaryotic system. We show the expression of the 30 kDa recombinant SARS-CoV-2 RBD-6×His in four different E. coli strains (at 28∘C using 0.25mM IPTG) including the expression strain E. coli BL21 (DE3) Rosetta Gami. SARS-CoV-2 rRBD-6×His protein was purified, refolded, and used as an antigen coat to assess antibody response in human sera against SARS-CoV-2 infection. The assessment was carried out using a total of 155 human sero-positive and negative SARS-CoV-2 antibodies. The ELISA showed 69.5% sensitivity, 88% specificity, 78.5% agreement, a positive predictive value (PPV) of 92.3%, and a negative predictive value of 56.5%. Moreover, the optical density (OD) values of positive samples significantly correlated with the commercial kit titers. Specific human antibodies against SARS-CoV-2 spike protein were detected by rapid in-house ELISA in sera of human COVID-19-infected patients. The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications, particularly in developing countries. Future studies are planned for the use of the generated SARS-CoV-2 rRBD-6×His protein in vaccine development and other diagnostic applications.

Antibody response to herpes simplex virus-1 is increased in autoimmune encephalitis.

Antibody response to herpes simplex virus-1 is increased in autoimmune encephalitis.

Influenza virus-like particle vaccine containing both apical membrane antigen 1 and microneme-associated antigen proteins of Plasmodium berghei confers protection in mice

BackgroundApical membrane antigen 1 (AMA1) and microneme-associated antigen (MIC) of Plasmodium parasites are important factors involved in host cell invasion.MethodsIn this study, influenza VLP vaccines containing both codon-optimized AMA1 and MIC were generated and the vaccine efficacy was evaluated in mice.ResultsVLPs vaccine immunization elicited higher levels of parasite-specific IgG and IgG2a antibody responses in sera. CD4+ and CD8+ T cells and germinal center B cells in blood, inguinal lymph nodes (ILN) and spleen were found to be significantly increased. Importantly, VLPs vaccination significantly reduced the levels of pro-inflammatory cytokines IFN-γ and TNF-α, decreased parasitemia in blood, resulting in lower body weight loss and longer survival time compared to control.ConclusionThese results indicated that VLPs containing P. berghei AMA1 and MIC could be a candidate for malaria blood-stage vaccine design.

Clinical relevance of increased antibody titres in older adults upon vaccination with squalene-adjuvanted versus non-adjuvanted influenza vaccines

In older adults, the serum antibody response to inactivated influenza vaccine (IIV) is often lower than in adolescents and non-elderly adults which may translate into suboptimal protection against influenza. To counteract this expression of immunosenescence, the use of adjuvanted IIV formulations has been explored. Four recent studies (three meta-analyses and one clinical trial) found an antibody increase of up to 1.5-fold in older adults, when a squalene-adjuvanted (MF59™) IIV was used. The clinical relevance of this increase may well continue to be a matter of debate. We would favour a threshold of 1.5 to consider an adjuvanted vaccine formulation superior to standard aqueous IIV because it exceeds the inevitable variation of antibody responses to non-adjuvanted IIV. It is also the same as the upper FDA equivalence limit for IIV lot-to-lot consistency. A corresponding threshold for the seroresponse rate difference could then be +5%.

Study of Antibodies to Influenza Neuraminidase N2.

Humoral immunity to influenza neuraminidase (NA) was evaluated among different groups of people including patients with acute influenza infection and healthy people in different age groups using an enzyme linked lectin assay (ELLA). The amino acid composition of NA of seasonal influenza viruses A/Victoria/361/2011(H3N2) and A/Hong Kong/4801/2014(H3N2) differed by 2%, while cross-reacting neuraminidase-inhibiting (NI) antibodies to them in the same serum samples were detected in 10% of cases. Middle-aged patients born from 1977 to 2000 had a high level of hemagglutination-inhibiting (HI) antibodies to A/Hong Kong/4801/2014(H3N2), but almost no NI antibodies, which may indicate that in the case of a change in the hemagglutinin (HA) subtype, this age group will be susceptible to influenza A/H3N2 viruses. Therefore, it could mean there is a need for priority vaccination of this age group with a vaccine against the appropriate strain. It was shown that after intranasal administration of live influenza vaccine (LAIV) for the 2017–2018 season, serum antibody response was not lower compared to that during natural infection. In older people, antibodies to archival A/H2N2 viruses were detected more often than to modern A/H3N2. Since the conversion of antibodies to HA and NA often did not coincide, antibodies to NA can serve as an additional criterion for assessing the immunogenicity of influenza vaccines.

Combined Subcutaneous-Intranasal Immunization With Epitope-Based Antigens Elicits Binding and Neutralizing Antibody Responses in Serum and Mucosae Against PRRSV-2 and SARS-CoV-2.

New vaccine design approaches, platforms, and immunization strategies might foster antiviral mucosal effector and memory responses to reduce asymptomatic infection and transmission in vaccinated individuals. Here, we investigated a combined parenteral and mucosal immunization scheme to induce local and serum antibody responses, employing the epitope-based antigens 3BT and NG19m. These antigens target the important emerging and re-emerging viruses PRRSV-2 and SARS-CoV-2, respectively. We assessed two versions of the 3BT protein, which contains conserved epitopes from the GP5 envelope protein of PRRSV-2: soluble and expressed by the recombinant baculovirus BacDual-3BT. On the other hand, NG19m, comprising the receptor-binding motif of the S protein of SARS-CoV-2, was evaluated as a soluble recombinant protein only. Vietnamese mini-pigs were immunized employing different inoculation routes: subcutaneous, intranasal, or a combination of both (s.c.-i.n.). Animals produced antigen-binding and neut1ralizing antibodies in serum and mucosal fluids, with varying patterns of concentration and activity, depending on the antigen and the immunization schedule. Soluble 3BT was a potent immunogen to elicit binding and neutralizing antibodies in serum, nasal mucus, and vaginal swabs. The vectored immunogen BacDual-3BT induced binding antibodies in serum and mucosae, but PRRSV-2 neutralizing activity was found in nasal mucus exclusively when administered intranasally. NG19m promoted serum and mucosal binding antibodies, which showed differing neutralizing activity. Only serum samples from subcutaneously immunized animals inhibited RBD-ACE2 interaction, while mini-pigs inoculated intranasally or via the combined s.c.-i.n. scheme produced subtle neutralizing humoral responses in the upper and lower respiratory mucosae. Our results show that intranasal immunization, alone or combined with subcutaneous delivery of epitope-based antigens, generates local and systemic binding and neutralizing antibodies. Further investigation is needed to evaluate the capability of the induced responses to prevent infection and reduce transmission.

Architecture and antigenicity of the Nipah virus attachment glycoprotein

Nipah virus (NiV) and Hendra virus (HeV) are zoonotic henipaviruses (HNVs) responsible for outbreaks of encephalitis and respiratory illness. The entry of HNVs into host cells requires the attachment (G) and fusion (F) glycoproteins, which are the main targets of antibody responses. To understand viral infection and host immunity, we determined a cryo-electron microscopy structure of the NiV G homotetrameric ectodomain in complex with the nAH1.3 broadly neutralizing antibody Fab fragment. We show that a cocktail of two nonoverlapping G-specific antibodies neutralizes NiV and HeV synergistically and limits the emergence of escape mutants. Analysis of polyclonal serum antibody responses elicited by vaccination of macaques with NiV G indicates that the receptor binding head domain is immunodominant. These results pave the way for implementing multipronged therapeutic strategies against these deadly pathogens.

Guideline for the treatment of chronic lymphocytic leukaemia

Guideline for the treatment of chronic lymphocytic leukaemia

Characterization of immune responses in fully vaccinated individuals after breakthrough infection with the SARS-CoV-2 delta variant.

Breakthrough infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have been reported frequently in vaccinated individuals with waning immunity. In particular, a cluster of over 1,000 infections with the SARS-CoV-2 delta variant was identified in a predominantly fully vaccinated population in Provincetown, Massachusetts in July 2021. In this study, vaccinated individuals who tested positive for SARS-CoV-2 (n=16) demonstrated substantially higher serum antibody responses than vaccinated individuals who tested negative for SARS-CoV-2 (n=23), including 32-fold higher binding antibody titers and 31-fold higher neutralizing antibody titers against the SARS-CoV-2 delta variant. Vaccinated individuals who tested positive also showed higher mucosal antibody responses in nasal secretions and higher Spike protein-specific CD8+ T cell responses in peripheral blood than did vaccinated individuals who tested negative. These data demonstrate that fully vaccinated individuals developed robust anamnestic antibody and T cell responses following infection with the SARS-CoV-2 delta variant. Moreover, these findings suggest that population immunity will likely increase over time by a combination of widespread vaccination and breakthrough infections.

Rationally designed immunogens enable immune focusing following SARS-CoV-2 spike imprinting.

Eliciting antibodies to surface-exposed viral glycoproteins can generate protective responses that control and prevent future infections. Targeting conserved sites may reduce the likelihood of viral escape and limit the spread of related viruses with pandemic potential. Here we leverage rational immunogen design to focus humoral responses on conserved epitopes. Using glycan engineering and epitope scaffolding in boosting immunogens, we focus murine serum antibody responses to conserved receptor binding motif (RBM) and receptor binding domain (RBD) epitopes following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike imprinting. Although all engineered immunogens elicit a robust SARS-CoV-2-neutralizing serum response, RBM-focusing immunogens exhibit increased potency against related sarbecoviruses, SARS-CoV, WIV1-CoV, RaTG13-CoV, and SHC014-CoV; structural characterization of representative antibodies defines a conserved epitope. RBM-focused sera confer protection against SARS-CoV-2 challenge. Thus, RBM focusing is a promising strategy to elicit breadth across emerging sarbecoviruses without compromising SARS-CoV-2 protection. These engineering strategies are adaptable to other viral glycoproteins for targeting conserved epitopes.

Towards a Four-Component GMMA-Based Vaccine against Shigella.

Shigellosis remains a major public health problem around the world; it is one of the leading causes of diarrhoeal disease in low- and middle-income countries, particularly in young children. The increasing reports of Shigella cases associated with anti-microbial resistance are an additional element of concern. Currently, there are no licensed vaccines widely available against Shigella, but several vaccine candidates are in development. It has been demonstrated that the incidence of disease decreases following a prior Shigella infection and that serum and mucosal antibody responses are predominantly directed against the serotype-specific Shigella O-antigen portion of lipopolysaccharide membrane molecules. Many Shigella vaccine candidates are indeed O-antigen-based. Here we present the journey towards the development of a potential low-cost four-component Shigella vaccine, eliciting broad protection against the most prevalent Shigella serotypes, that makes use of the GMMA (Generalized Modules for Membrane Antigens) technology, a novel platform based on bacterial outer membranes for delivery of the O-antigen to the immune system.

Mucosal Vaccination With Recombinant Tm-WAP49 Protein Induces Protective Humoral and Cellular Immunity Against Experimental Trichuriasis in AKR Mice.

Trichuriasis is one of the most common neglected tropical diseases of the world’s poorest people. A recombinant vaccine composed of Tm-WAP49, an immunodominant antigen secreted by adult Trichuris stichocytes into the mucosa of the cecum to which the parasite attaches, is under development. The prototype is being evaluated in a mouse model of Trichuris muris infection, with the ultimate goal of producing a mucosal vaccine through intranasal delivery. Intranasal immunization of mice with Tm-WAP49 formulated with the adjuvant OCH, a truncated analog of alpha-GalCer with adjuvanticity to stimulate natural killer T cells (NKT) and mucosal immunity, induced significantly high levels of IgG and its subclasses (IgG1 and IgG2a) in immunized mice. This also resulted in a significant reduction of worm burden after challenge with T. muris-infective eggs. The addition of QS-21 adjuvant to this vaccine formulation further reduced worm counts. The improved protection from the dual-adjuvanted vaccine correlated with higher serum antibody responses (IgG, IgG1, IgG2a, IgA) as well as with the induction of antigen-specific IgA in the nasal mucosa. It was also associated with the robust cellular responses including functional subsets of CD4 T cells producing IL-4, and cytotoxic CD8 T cells expressing granzyme B. The worm reduction achieved by mucosal immunization was higher than that induced by subcutaneous immunization. Intranasal immunization also induced a significantly higher nasal mucosa-secreted antigen-specific IgA response, as well as higher functional cellular responses including CD4+IL4+ (Th1) and CD8+GnzB+ (Th2) T cells, and antigen-specific INFγ-producing T cells in both spleen and MLNs and antibody-producing B cells (CD19+B220+/B220+GL7+). Mucosal immunization further induced long-term T lymphocyte memory with increased central (CD62L+CD44+) and effector (CD62L-CD44+) memory subsets of both CD4 and CD8 T cells at 60 days after the last immunization. In summary, intranasal immunization with recombinant Tm-WAP49 protein induced strong protection versus murine trichuriasis. It represents a promising vaccination approach against intestinal nematodes.

Exercise after influenza or COVID-19 vaccination increases serum antibody without an increase in side effects

Vaccination is an effective public health measure, yet vaccine efficacy varies across different populations. Adjuvants improve vaccine efficacy but often increase reactogenicity. An unconventional behavioral “adjuvant” is physical exercise at the time of vaccination. Here, in separate experiments, we examined the effect of 90-minute light- to moderate-intensity cycle ergometer or outdoor walk/jog aerobic exercise performed once after immunization on serum antibody response to three different vaccines (2009 pandemic influenza H1N1, seasonal influenza, and COVID-19). Exercise took place after influenza vaccination or after the first dose of Pfizer-BioNTech COVID-19 vaccine. A mouse model of influenza A immunization was used to examine the effect of exercise on antibody response and the role of IFNα as a potential mechanism by treating mice with anti-IFNα antibody. The results show that 90 min of exercise consistently increased serum antibody to each vaccine four weeks post-immunization, and IFNα may partially contribute to the exercise-related benefit. Exercise did not increase side effects after the COVID-19 vaccination. These findings suggest that adults who exercise regularly may increase antibody response to influenza or COVID-19 vaccine by performing a single session of light- to moderate-intensity exercise post-immunization.

Increased Breadth of Group A Streptococcus Antibody Responses in Children With Acute Rheumatic Fever Compared to Precursor Pharyngitis and Skin Infections.

BackgroundGroup A Streptococcus (GAS) causes superficial pharyngitis and skin infections as well as serious autoimmune sequelae such as acute rheumatic fever (ARF) and subsequent rheumatic heart disease. ARF pathogenesis remains poorly understood. Immune priming by repeated GAS infections is thought to trigger ARF, and there is growing evidence for the role of skin infections in this process.MethodsWe utilized our recently developed 8-plex immunoassay, comprising antigens used in clinical serology for diagnosis of ARF (SLO, DNase B, SpnA), and 5 conserved putative GAS vaccine antigens (Spy0843, SCPA, SpyCEP, SpyAD, Group A carbohydrate), to characterize antibody responses in sera from New Zealand children with a range of clinically diagnosed GAS disease: ARF (n = 79), GAS-positive pharyngitis (n = 94), GAS-positive skin infection (n = 51), and matched healthy controls (n = 90).ResultsThe magnitude and breadth of antibodies in ARF was very high, giving rise to a distinct serological profile. An average of 6.5 antigen-specific reactivities per individual was observed in ARF, compared to 4.2 in skin infections and 3.3 in pharyngitis.ConclusionsARF patients have a unique serological profile, which may be the result of repeated precursor pharyngitis and skin infections that progressively boost antibody breadth and magnitude.

P417 Seroconversion after COVID-19 Vaccination in Inflammatory Bowel Disease Patients

BackgroundData about the effect of different immunosuppressive treatments of IBD patients on seroconversion and on different SARS-CoV-2 vaccinations are scarce. To avoid impaired vaccine responses and worse outcome of COVID-19, factors attenuating protective immunity shoud be shought.MethodsAnti SARS-CoV-2S antibody levels of IBD patients in remission were measured by immunoassay (Roche) before vaccination and on the second week. Antibody responses were compared among different treatment groups (biologics, combination, azathioprin, without immunomodulation) and between mRNA and other type of vaccines. Anti TNF alpha levels were also assesed, 24 hours before vaccination considering correlation with seroconversion.ResultsThirty-eight (31.7%) ulcerative colitis and eighty-two (68,2%) Crohn’s disease patients were included (median age, 39.1 years, 53.3% female). No serious comorbidities were present. Eighty-two patients (68.3%) were on biological therapy, fifty-two (43%) were treated with azathioprine alone or in combination. Two doses of mRNA vaccines were administered to ninty-eight patients ((81,7%) Moderna:, 20, Pfizer:, 78). The other type of vaccines were AstraZeneca (16) Sputnik V (3) and Sinopharm (3). The median anti-SARS-CoV-2S antibody level was, 2733 U/mL (IQR:, 535–7764) on the, 14th day after vaccination (IQR:, 14–17). Significant differences were revealed between the groups of patients treated with biological agents or non-biological therapy (median:, 1649 U/ml vs., 5711.5 U/ml; p=0.013) and between patients recieving mRNA and non-mRNA vaccine (median:, 3367.5 U/ml vs., 392.6 U/ml;p<0.001). Considering the varying effect of immunosupression related to combination therapy, biological drugs, azathioprin and other non-immunomodulating treatments antibody response were assesed in these groups also. The median antibody levels were, 850,5 U/ml (IQR:, 251.0–4899.5), 1837 U/ml (IQR:, 544.5–5902), 3141 U/ml (IQR:, 1066–7988), 7764 U/ml (IQR:, 5601–13808) demonstrating significant differences among them (p<0.001). No correlation between anti-TNF-alpha serum level and antibody response were found.ConclusionAltough all vaccines cause seroconversion in IBD patients who are in remission, the rate of seroconversion is lower in patients treated with immunosupressant, biological agent or combo therapy or recieving non-mRNA vaccines. As the level of anti-TNF-alpha agents do not affect the rate of seroconversion there is probably no need for matching the time of vaccination and anti-TNF therapy.

DOP53 In-depth characterisation of the serum antibody epitope repertoire in Inflammatory Bowel Disease by high-throughput phage-displayed immunoprecipitation sequencing

Abstract Background Patients with IBD show distinct antibody responses, particularly against microbiota. However, a comprehensive overview of the antibody epitope repertoire in IBD is lacking. Here, we characterized serum antibody responses in patients with IBD and population controls using a high-throughput phage-displayed immunoprecipitation sequencing (PhIP-seq) workflow and associated these to disease phenotypes and the faecal microbiome. Methods PhIP-seq was leveraged to characterise antibody responses against 344,000 rationally selected peptide antigens in 497 patients with IBD which were compared with 1,326 individuals from a population-based cohort (Fig. 1A-B). Antibody profiles were linked to 23 IBD-specific clinical features such as disease location and surgical history and to faecal microbiota composition (Fig. 1C). Results Patients with IBD demonstrated distinct antibody epitope repertoires compared with individuals from the general population, with 373 differentially abundant antibody-bound peptides (202 overrepresented, 171 underrepresented) belonging to bacterial flagellins (69), virulence factors (102), other antigens of both commensal and pathogenic bacteria (90) as well as viruses (67) and food proteins (24) (Figure 2). In particular, antibody responses against bacterial flagellins, many of which belong to Lachnospiraceae bacteria (e.g. Roseburia spp.), but also Eubacterium spp. and pathogens (e.g. Legionella, Clostridium, Burkholderia) dominated in patients with Crohn’s disease (CD), and were associated with ileal disease involvement and more complicated disease behaviour (e.g. fibrostenotic disease, surgical history) as well as anti-Saccharomyces cerevisiae antibody positivity. Furthermore, many other antigens were newly identified, e.g. decreased responses to E. coli virulence factors and genome polyproteins of enteroviruses, and increased responses to food antigens (wheat, barley) and autoantigens (particularly collagen type I and VI). Antibody epitope repertoires were able to accurately discriminate CD from population controls (area under the curve [AUC]=0.88, test set evaluation), showing very high discriminative performance (positive and negative predictive value of 72% and 93%, respectively, representing predicted classes in test set) (Fig. 3A-C), which was less accurate for ulcerative colitis (UC) (Fig. 3D-F). Conclusion This study demonstrates the size, diversity and complexity of systemic antibody epitope repertoires in patients with IBD compared to controls, showing that distinct clinical phenotypes of IBD are characterized by unique antibody signatures. PhIP-seq is a powerful tool for identifying systemic immune-based biomarkers and exposing novel immunological targets in immune-mediated inflammatory diseases like IBD.

Orally Administrated Recombinant Vaccinia Virus Displaying ROP4 Induces Protection against Toxoplasma gondii Challenge Infection.

Recombinant vaccinia viruses (rVVs) are attenuated viruses and are widely utilized as vectored vaccine platforms against numerous diseases. However, the protective efficacy of these rVV vaccines against Toxoplasma gondii and the resulting mucosal immunity has not been thoroughly assessed. Here, rVVs expressing the rhoptry protein 4 (ROP4) of T. gondii were generated. To evaluate the protection induced by the vaccines, mice were orally immunized with the ROP4-rVVs and subsequently challenge-infected with a lethal dose of T. gondii ME49 strain. Immunization with the rVVs induced higher levels of parasite-specific IgG and IgA antibody responses in sera compared to unimmunized control (NC). Upon challenge infection, significantly higher levels of IgG or IgA antibody responses in the brain, intestines, and vaginal samples were found in the immunized mice compared to NC. The ROP4-rVV vaccination elicited potent IgG and IgA secreting cell (ASC) responses, while substantially enhancing germinal center B cell, as well as CD4+ and CD8+ T cell responses from lymphoid organs. The production of pro-inflammatory cytokines IFN-γ and IL-6 in the brains was markedly diminished following immunization. The immunized mice also experienced reduced bodyweight loss and possessed fewer brain cysts than the control group. These results suggest that oral delivery of ROP4 displaying rVVs induced mucosal and systemic immunities that contributed to protection against lethal T. gondii challenge infection.

Development and evaluation of NS1 protein based i-ELISA for serodiagnosis of Bluetongue disease

Bluetongue (BT) is an important viral disease of small ruminants and causes major economic losses in India. For serodiagnosis of BT, recombinant antigen-based assays are considered as alternatives to conventional approaches such as serum neutralization test. The present study aimed at the development of an indirect- enzyme-linked immunosorbent assay (i-ELISA) using bluetongue (BTV) recombinant NS1. NS1 gene of BTV encoding a mature NS1 protein was produced as a recombinant protein (rNS1) in Escherichia coli. The immunogenic potential of purified rNS1 was confirmed by detecting specific NS1 antibody responses in sera collected from immunized sheep using ELISA. An i-ELISA based on rNS1 was developed and optimized. In comparison to a commercially available c-ELISA kit, in the detection of BTV specific antibodies, this new assay exhibited a diagnostic sensitivity of 91.2%. This study highlighted the potential utility of rNS1 protein as a safe and novel diagnostic reagent in comparison to live virus antigen, in the development of serodiagnostic assay for surveillance of BTV infection in sheep and goats.

Orally administered antigen can reduce or exacerbate pathology in an animal model of inflammatory arthritis dependent upon the timing of administration.

Currently, treatments for rheumatoid arthritis (RA) are focussed on management of disease symptoms rather than addressing the cause of disease, which could lead to remission and cure. Central to disease development is the induction of autoimmunity through a breach of self-tolerance. Developing approaches to re-establish antigen specific tolerance is therefore an important emerging area of RA research. A crucial step in this research is to employ appropriate animal models to test prospective antigen specific immunotherapies. In this short communication, we evaluate our previously developed model of antigen specific inflammatory arthritis in which ovalbumin-specific T cell receptor transgenic T cells drive breach of tolerance to endogenous antigens to determine the impact that the timing of therapy administration has upon disease progression. Using antigen feeding to induce tolerance we demonstrate that administration prior to articular challenge results in a reduced disease score as evidenced by pathology and serum antibody responses. By contrast, feeding antigen after initiation of disease had the opposite effect and resulted in the exacerbation of pathology. These preliminary data suggest that the timing of antigen administration may be key to the success of tolerogenic immunotherapies. This has important implications for the timing of potential tolerogenic therapies in patients.