The humoral immune response is essential for successful vaccine protection against paratuberculosis in sheep

Background

The role played by the humoral immune response in animals vaccinated against a mycobacterial disease such as paratuberculosis, is not well understood. Sheep vaccinated against Mycobacterium avium subsp. paratuberculosis (MAP) can still become infected and in some cases succumb to clinical disease. The strength and location of the humoral immune response following vaccination could contribute to the ability of sheep to clear MAP infection. We examined the peripheral antibody response along with the localised humoral response at the site of paratuberculosis infection, the ileum, to better understand how this contributes to MAP infection of sheep following vaccination and exposure.

Results

Through assessing MAP specific serum IgG1 and IgG levels we show that the timing and strength of the humoral immune response directly relates to prevention of infection following vaccination. Vaccinated sheep that subsequently became infected had significantly reduced levels of MAP specific serum IgG1 early after vaccination. In contrast, vaccinated sheep that did not subsequently become infected had significantly elevated MAP specific serum IgG1 following vaccination. Furthermore, at 12 months post MAP exposure, vaccinated and subsequently uninfected sheep had downregulated expression of genes related to the humoral response in contrast to vaccinated infected sheep where expression levels were upregulated.

Conclusions

The timing and strength of the humoral immune response following vaccination against paratuberculosis in sheep directly relates to subsequent infection status. An initial strong IgG1 response following vaccination was crucial to prevent infection. Additionally, vaccinated uninfected sheep were able to modulate that response following apparent MAP clearance, unlike vaccinated infected animals where there was apparent dysregulation of the humoral response, which is associated with progression to clinical disease.

Minimal uranium immunotoxicity following a 60-day drinking water exposure to uranyl acetate in male and female C57BL/6J mice

Historical uranium (U) mining in the Southwestern United States resulted in significant environmental contamination throughout this region and presents a significant risk of chronic metal exposure and toxicity for communities living in close proximity to mine waste sites. Uranium exposure is associated with numerous deleterious health effects including immune dysfunction; however, its effects on the immune system have yet to be fully characterized. We recently published that drinking water exposure to U, in the form of uranyl acetate (UA), results in low overall tissue retention of U (<0.01%), with very little accumulation in immune organs (blood, bone marrow, spleen, and thymus) of male and female mice. In the present study we characterized the immunotoxicity of U, in the form of UA, following a 60-day drinking water exposure to 5 and 50 ppm in male and female C57BL/6J mice. The following immunotoxicity endpoints were evaluated: hematology, immune tissue weights and total cell recoveries, immunophenotying of the spleen and thymus, and immune cell function (lymphocyte mitogenesis and T-dependent antibody response). Uranium exposure had subtle impacts on the immune endpoints evaluated, likely due to low U accumulation at these sites. The only significant alterations were a slight decrease in the percentages of splenic natural killer T-cells and macrophages in exposed male mice. Despite minimal immunological effects, this study highlights the importance of investigating toxicological endpoints in both sexes and developing accurate animal models that model epidemiological exposures in the future.

Analgesic adjuvants modulate morphine-induced immune effects in mice

BACKGROUND

Macrophages, involved in the pathogenesis of pain, express a variety of receptors enabling responsiveness to certain medications, including adjuvant analgesics (AAs), that are effective in neuropathic pain and include drugs not primarily indicated for pain treatment, such as anticonvulsants or antidepressants. Their analgesic effects are likely associated with immunomodulatory activity, that remain undefined. Thus, current research aimed at examining the impact of AAs on morphine-induced effects exerted on mouse immunity.

METHODS

Macrophages from mice treated with morphine with or without gabapentin, amitriptyline or venlafaxine, were either subjected to phagocytosis assay, cultured to evaluate the generation of cytokines, or were pulsed with either corpuscular antigen or hapten and transferred to naive recipients to induce humoral or cellular response, respectively. Active contact hypersensitivity was also elicited in drug-treated mice.

RESULTS

We observed that repeatedly administered morphine and AAs reduced antigen phagocytosis by macrophages. Further, amitriptyline with morphine enhanced basal secretion of cytokines by macrophages, and all drugs tended to decrease LPS-stimulated release of pro-inflammatory cytokines. Morphine and AAs impacted the expression of phagocytosis and antigen-presentation markers on macrophages, which led to the reduced ability of morphine-affected macrophages to induce B-cell secretion of specific antibodies, and the addition of AAs strengthened this effect. Finally, gabapentin and venlafaxine suppressed the contact hypersensitivity reaction, while amitriptyline seemed to have the opposite effect.

CONCLUSIONS

Our study demonstrated a significant anti-inflammatory activity of AAs across a broad spectrum of macrophage immune functions, which is likely critical to their analgesic activity supporting the beneficial effect of morphine.

Dysregulation of humoral immunity in Foxp3 conditional-knockout mice

Foxp3⁺ regulatory T cells (Tregs) are crucial for maintaining tolerance to self-antigens and preventing autoimmune diseases. Loss of Foxp3 expression leads to autoimmunity and disrupts humoral immune responses, including hyperproduction of immunoglobulin E (IgE). Elucidation of how Tregs control antibody production can lead to the development of new therapies for autoimmune and allergic diseases. However, premature death of Foxp3-deficient mice makes it difficult to analyze the roles of Tregs in humoral immunity of adult mice. In this study, we developed Foxp3 conditional-knockout mice (Foxp3^floxR26^CreERT2) in which the Foxp3 gene was inducibly deleted by tamoxifen administration. After oral administration of tamoxifen, titers of immunoglobulins, particularly IgG2c and IgE, were increased in Foxp3^floxR26^CreERT2 mice compared with that in controls. Under these conditions, CD4⁺ T cells from Foxp3^floxR26^CreERT2 mice had increased expression of several activation markers, including inducible costimulator and CD40 ligand, as well as the cytokines interleukin 4 and interferon gamma. In addition, the proportions of T follicular helper (Tfh) cells and germinal center (GC) B cells were increased in Foxp3^floxR26^CreERT2 mice compared with those in controls. These results indicated that Tregs controlled excessive or pathogenic antibody production by suppressing Tfh cell differentiation and GC formation. Furthermore, these data suggested that Foxp3^floxR26^CreERT2 mice could be a useful tool for screening therapeutic agents.

Seasonal influenza vaccines induced high levels of neutralizing cross-reactive antibody responses against different genetic group influenza A(H1N1)pdm09 viruses

Influenza A(H1N1)pdm09 viruses have been circulating throughout the world since the 2009 pandemic. A/California/07/2009 (H1N1) virus was included in seasonal influenza vaccines for seven years altogether, providing a great opportunity to analyse vaccine-induced immunity in relation to the postpandemic evolution of the A(H1N1)pdm09 virus. Serum antibodies against various epidemic strains of influenza A(H1N1)pdm09 viruses were measured among health care workers (HCWs) by haemagglutination inhibition and microneutralization tests before and after 2010 and 2012 seasonal influenza vaccinations. We detected high responses of vaccine-induced neutralizing antibodies to six distinct genetic groups. Our results indicate antigenic similarity between vaccine and circulating A(H1N1)pdm09 strains, and substantial vaccine-induced immunity against circulating epidemic viruses.

Leishmania infantum-specific IFN-γ production in stimulated blood from cats living in areas where canine leishmaniosis is endemic

Background

Feline leishmaniosis caused by Leishmania infantum is considered a rare disease in endemic areas, whereas subclinical infections are common. Immune response plays a key role in driving the course of L. infantum infection in other host species; however, the feline cell-mediated immune response to L. infantum infection has not yet been investigated. The aim of this study was to determine the cell-mediated immune response specific to L. infantum by means of interferon (IFN)-γ release in whole blood assay from cats living in endemic areas (66 in Sicily and 113 in Catalonia) and to compare with antibody levels to L. infantum [enzyme-linked immunosorbent assay (ELISA) and immunofluorescence antibody test (IFAT)], blood parasite load and retroviral infections.

Results

Most cats (n = 140) were L. infantum antibody negative and only 22% (n = 39) were positive. Only 9 and 2% of tested cats had a feline immunodeficency virus (FIV) infection or a feline leukemia virus (FeLV) infection, respectively. Thirty-two cats out of 179 (18%) produced IFN-γ after stimulation with L. infantum soluble antigen (LSA) while the majority of cats (93%) produced IFN-γ after stimulation with concanavalin A (ConA). Six LSA-IFN-γ-producer cats were seropositive (three to ELISA and five to IFAT) but they were polymerase chain reaction (PCR) negative, while only one cat was antibody- and PCR-positive. Significant positive correlations were found between IFN-γ concentrations after stimulation with LSA and ConA, and between serology and PCR testing. No association was found between FIV status and LSA or ConA-IFN-γ production. Combining PCR, serology and specific IFN-γ concentration results, we found that 36% of cats studied were exposed to L. infantum.

Conclusions

As expected, cats from endemic areas produce IFN-γ after ex vivo blood stimulation with LSA and therefore are able to activate a cell-mediated adaptive immune response against the parasite that is variably associated with antibody or blood PCR positivity. The association of this assay to serological and molecular tests provides a better estimate of cat exposure to L. infantum.

Humoral immune response to repeated lumpy skin disease virus vaccination and performance of serological tests

BACKGROUND

In the presented study we investigated the development of the humoral immune response against LSDV during the process of re-vaccination of cattle over a time span of 5 months. In addition, the performance of different serological techniques for antibody detection against LSDV was compared. For sample collection, an area without previous LSD outbreak reports in Serbia was selected. Seventy-nine cattle from twenty farms vaccinated in 2016 and re-vaccinated in 2017 were included in the study. Two farms from the same area with good calving management were selected for investigation of passive LSDV antibody transfer from vaccinated mothers to new-borne calves.

RESULTS

All investigated cattle were healthy on the day of vaccination and during the whole study. Swelling at the injection site or other side effects of vaccination did not occur after re-vaccination in the study. Detection of LSD-specific antibodies was performed with the standard serological methods VNT and IFAT as well as a commercially available Capripox double antigen multi-species-ELISA. Capripoxvirus-specific antibodies were detected 46 to 47 weeks after vaccination in 2016, with VNT in 35.06% and with IFAT and ELISA in 33.77%. A secondary response was observed in all three tests 1 month after re-vaccination with a significant increase in seropositive animals compared to the results before re-vaccination. With all applied serological methods, the number of animals testing positive was significantly higher at 1 and 5 months post re-vaccination than before re-vaccination. No significant statistical difference (p > 0.05) was observed between the results of all three tests used. The sensitivity and specificity of ELISA was estimated to be SeELISA 91% and SpELISA 87% calculated by the results of VNT and SeELISA 88% and SpELISA 76% calculated by the results of IFAT. Passive antibody transfer from vaccinated mothers to new-born calves was investigated at 14 days after birth. Discrepancies for the detection of LSDV specific antibodies between cows and newborn calves at the age of 14 days were observed in VNT and IFAT, but not in ELISA.

CONCLUSION

Of all tests used the commercially available ELISA shows to be the most useful for high throughput analysis compared to VNT or IFAT.

Longitudinal analysis of acute and convalescent B cell responses in a human primary dengue serotype 2 infection model

BACKGROUND

Acute viral infections induce a rapid and transient increase in antibody-secreting plasmablasts. At convalescence, memory B cells (MBC) and long-lived plasma cells (LLPC) are responsible for long-term humoral immunity. Following an acute viral infection, the specific properties and relationships between antibodies produced by these B cell compartments are poorly understood.

METHODS

We utilized a controlled human challenge model of primary dengue virus serotype 2 (DENV2) infection to study acute and convalescent B-cell responses.

FINDINGS

The level of DENV2 replication was correlated with the magnitude of the plasmablast response. Functional analysis of plasmablast-derived monoclonal antibodies showed that the DENV2-specific response was dominated by cells producing DENV2 serotype-specific antibodies. DENV2-neutralizing antibodies targeted quaternary structure epitopes centered on domain III of the viral envelope protein (EDIII). Functional analysis of MBC and serum antibodies from the same subjects six months post-challenge revealed maintenance of the serotype-specific response in both compartments. The serum response mainly targeted DENV2 serotype-specific epitopes on EDIII.

INTERPRETATION

Our data suggest overall functional alignment of DENV2-specific responses from the plasmablast, through the MBC and LLPC compartments following primary DENV2 inflection. These results provide enhanced resolution of the temporal and specificity of the B cell compartment in viral infection and serve as framework for evaluation of B cell responses in challenge models.

FUNDING

This study was supported by the Bill and Melinda Gates Foundation and the National Institutes of Health.

Altered immunogenicity of 23-valent pneumococcal polysaccharide vaccine in elderly patients with diabetes who revealed lower responses to concomitant administration of BIKEN varicella zoster vaccine: Results of post hoc analysis of a randomized double-blind trial

AIMS

This double-blind randomized controlled study of 52 elderly patients with diabetes assessed cell-mediated immunity and safety of BIKEN varicella-zoster vaccine (BVZV). Cellular and humoral responses to VZV at 3 months after BVZV and 23-valent polysaccharide pneumococcal vaccine (PPSV23) vaccination elicited poor results. Post-hoc analyses assessed the effects of immunogenicity of PPSV23.

METHODS

Using standardized enzyme-linked immunosorbent assay, pneumococcal 6B and 23F serotype-specific immunoglobulin G (IgG)-binding antibody concentrations were measured in stored samples retrospectively before administration and 3 months after. Responders increased more than twofold in at least one serotype-specific IgG.

RESULTS

The geometric mean concentration ratio (GMCR) of serum anti-pneumococcal 6B IgG was 1.76 (95%C.I.: 0.58, 5.34) in patients receiving concurrent PPSV23 and BVZV, compared to 2.39 (95%C.I.: 0.53, 10.76) in patients receiving PPSV23 and placebo (P = .055). The GMCR of serum anti-pneumococcal 23F IgG was 2.54 (95%C.I.: 0.57, 11.43) in PPSV23/BVZV vaccinees compared to 3.34 (95%C.I.: 0.84, 12.92) in PPSV23/placebo vaccinees (P = .424). Responder rates, those who developed antibodies to either/both serotypes, were 68% in the BVZV group and 85% in the placebo group (P = .007).

CONCLUSIONS

Results suggest that concurrent administration of BVZV influenced humoral responses to PPSV23 in elderly subjects with diabetes.

Differential durability of immune responses to measles and mumps following MMR vaccination

The development and wide-spread use of mumps vaccine resulted in a dramatic and sustained decrease in the incidence of mumps disease; however, since 2000, an increase in the size and number of mumps outbreaks in the United States and other countries has sparked renewed interest in the durability of mumps-specific immunity elicited by mumps vaccination. The most likely explanation for mumps cases in previously immunized persons may be secondary vaccine failure, or waning immunity. In the current study, we examined changes in markers of measles and mumps immunity at two timepoints, approximately 7 and 17 years after two-dose MMR-II® vaccination, in a cohort of 98 healthy adults. Our results indicate that mumps IgG titers exhibited a large and significant decline during this time period, while mumps neutralizing Ab titers were relatively stable. There was a similar discrepancy with measles-specific immune responses. For both pathogens, neutralizing antibody titers were fairly low and, given the length of time since vaccination, may have already declined. These data suggest that specific immune outcomes may wane at different rates and highlight our currently incomplete understanding of protective immune responses to mumps and measles.

Targeting the CD40-CD40L pathway in autoimmune diseases: Humoral immunity and beyond

CD40 is a TNF receptor superfamily member expressed on both immune and non-immune cells. Interactions between B cell-expressed CD40 and its binding partner, CD40L, predominantly expressed on activated CD4+ T cells, play a critical role in promoting germinal center formation and the production of class-switched antibodies. Non-hematopoietic cells expressing CD40 can also engage CD40L and trigger a pro-inflammatory response. This article will highlight what is known about the biology of the CD40-CD40L axis in humans and describe the potential contribution of CD40 signaling on both hematopoietic and non-hematopoietic cells to autoimmune disease pathogenesis. Additionally, novel therapeutic approaches to target this pathway, currently being evaluated in clinical trials, are discussed.

Effect of atorvastatin on humoral immune response to 23-valent pneumococcal polysaccharide vaccination in healthy volunteers: The StatVax randomized clinical trial

BACKGROUND

The immunomodulatory effects of statins on vaccine response remain uncertain. Therefore, the objective of this study was to determine if atorvastatin enhances pneumococcal-specific antibody titer following 23-valent pneumococcal polysaccharide vaccination.

METHODS

Double-blind, placebo-controlled, single-center randomized clinical trial entitled StatVax. Subjects were enrolled between June and July 2014 and followed up through September 2014. 33 healthy volunteers signed informed consent after volunteer sampling. 11 participants were excluded; 22 healthy volunteers without prior pneumococcal vaccination were enrolled and completed the study. Participants were randomized to receive a 28-day course of 40 mg atorvastatin (n = 12) or matching lactose placebo (n = 10). On day 7 of treatment, Pneumovax 23 was administered intramuscularly. The primary outcome was fold change in total pneumococcal-specific antibody titer determined by a ratio of post-vaccination titer over baseline titer. Secondary outcomes included serotype-specific pneumococcal antibody titer, seroconversion, complete blood counts (CBC), erythrocyte sedimentation rate (ESR), and serum cytokine analysis.

RESULTS

Of the 22 randomized patients (mean age, 23.86; SD, 4.121; 11 women [50%]), 22 completed the trial. Total anti-pneumococcal antibody titer in the atorvastatin group went from a baseline mean of 32.58 (SD, 15.96) to 147.7 (SD, 71.52) μg/mL at 21 days post-vaccination while titer in the placebo group went from a mean of 30.81 (SD, 13.04) to 104.4 (SD, 45) μg/mL. When comparing fold change between treatment groups, there was a significant increase in fold change of total anti-pneumococcal antibody titer in the atorvastatin group compared to the placebo group (2-way ANOVA, p = .0177).

CONCLUSIONS

Atorvastatin enhances antigen-specific primary humoral immune response to a T cell-independent pneumonia vaccination. Pending confirmation by larger cohort studies of target populations, peri-vaccination conventional doses of statins can become a novel adjuvant for poorly-immunogenic polysaccharide-based vaccines.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02097589.

The clinical implication of gamma globulin levels in patients with nonmuscle-invasive bladder cancer

OBJECTIVE

The production of antibody, also referred immunoglobulin, is the principal functions of B cells. Gamma globulin fraction determined by serum protein electrophoresis is composed almost entirely of immunoglobulin. This study aimed to investigate the association between gamma globulin level and oncological outcomes in patients with nonmuscle-invasive bladder cancer (NMIBC).

PATIENTS AND METHODS

A total of 274 patients with NMIBC who underwent transurethral surgery between 2000 and 2015 were identified. One hundred forty-four patients (52.6%) had received adjuvant intravesical bacillus Calmette-Guérin. Gamma globulin fraction (%) was determined by serum protein electrophoresis, and gamma globulin level (mg/dl) was calculated by multiplying the total protein level (mg/dl) by the gamma globulin fraction (%). The association between gamma globulin levels and oncological outcomes was statistically evaluated.

RESULTS

During a median follow-up period of 39 months, 99 (36.1%) patients experienced at least 1 tumor recurrence and 16 (5.8%) patients had disease progression. The median (interquartile range) gamma globulin level was 1.2 (1.0-1.3) mg/dl. Recurrence-free survival rate of patients with gamma globulin levels of ≥1.4 mg/dl was significant lower than that of patients with gamma globulin levels of <1.4 mg/dl (P < 0.01). There was no significant difference in progression-free survival between the 2 groups (P = 0.17). Multivariate analysis revealed that gamma globulin level of ≥1.4 mg/dl is significantly associated with higher recurrence rate (hazard ratio = 1.83, P < 0.01).

CONCLUSION

Gamma globulin level is significantly associated with tumor recurrence. Our results suggest that B cell immunity may be involved in tumor recurrence in patients with NMIBC.

An Efficient Method to Generate Monoclonal Antibodies from Human B Cells

In the age of personalized medicine, an efficient method to generate monoclonal antibodies (mAbs) is essential for biomedical and immunotherapeutic research. Numerous aspects of basic B-cell biology can be studied at the monoclonal level, including B-cell development, antibody responses to infection or vaccination, and autoimmune responses. Single-cell B-cell receptor cloning allows for the rapid generation of antigen-specific mAbs in a matter of several weeks. In this chapter, we provide an efficient method to generate mAbs from peripheral blood plasmablasts and memory B cells induced by infection and vaccination. Additionally, we provide a protocol on how to optimize single-cell B-cell sorting for both single-cell B-cell receptor cloning and single-cell RNA-sequencing, for the application of studying B-cell specificity and function (spec-seq). This protocol can be easily adapted for other B-cell populations, B cells in tissues, and B cells from other organisms.

[Effect of Acupuncture Plus Moxibustion on Immune Function in Patients with Bra-chiocephalic Takayasu Arteritis]

OBJECTIVE

To observe the influence of acupuncture and moxibustion on humoral immunity and cellular immunity related indexes in patients with bra-chiocephalic Takayasu arteritis (BCTA), so as to explore its underlying mechanisms in the treatment of Takayasu arteritis (TA).

METHODS

A total of 31 BCTA patients (9 men and 22 women at age of 16-70 years) were treated by manual acupuncture stimulation of main acupoint Renying(ST 9)and auxillary acupoints as Jiquan (HT 1), Chize (LU 5), Fengchi (GB 20), bilateral Xinshu (BL15), Feishu (BL 13) and Geshu (BL 17), Jingming (BL 1), etc. according to clinical symptoms, with the needles retained for 20 min. Additionally, moxibustion was applied to Taiyuan (LU 9), BL 15, BL 13 and BL 17. The treatment was conducted twice daily for 4 weeks. Serum IgG, IgA, IgM, IgE, C_{3 ,} C₄ contents, and CD 3^＋， CD 4^＋， CD 8^＋ T lymphocytes contents were assayed by using immue turbidimetry and cell counting.

RESULTS

Before the treatment and in these 31 BCTA patients, an abnormal increase was found in serum IgG content in 10 cases, IgM in 3 cases, IgE in 3 cases, C₃ in 11 cases, CD 4^＋ in 6 cases, and CD 8^＋ in 9 cases, and an abnormal decrease was found in serum CD 3^＋ level in 11 cases, CD 4^＋ in 7 cases, as well as CD 8^＋ in 4 cases. After the treatment, the increased levels of IgG, IgM, C_3, CD 4^＋ and CD 8^＋ in patients with abnormally higher values were considerably down-regulated (P<0.05), the decreased levels of CD 3^＋， CD 4^＋ and CD 8^＋ in patients with abnormally lower values were evidently up-regulated (P<0.05). No significant changes were found in IgG, IgA, IgM, IgE, C₃ and C_4, CD 3^＋ and CD 8^＋ in patients with normal values of these indexes after the treatment (P>0.05). The CD 4^＋ level in patients with normal value was significantly deun-regulated after the treatment (P<0.05), but still in the range of normal value.

CONCLUSION

Acupuncture plus moxibustion can regulate some of the abnormally elevated and lowered humoral immunity and cellular immunity related indexes in BCTA patients, possibly having a favorable role in the treatment of BCTA.

Seasonal variations in cellular and humoral immunity in male striped hamsters (Cricetulus barabensis)

Animals in the non-tropical zone usually demonstrate seasonal variations in immune function, which is important for their survival. In the present study, seasonal changes in immunity in striped hamsters (Cricetulus barabensis) were investigated to test the winter immunoenhancement hypothesis. Male hamsters were captured from the wild in the fall and winter of 2014 and in the spring and summer of 2015. Body mass, body fat mass and blood glucose levels of the hamsters were all highest in the summer, whereas relative fatness and thymus mass had no seasonal changes. Spleen mass was highest in the fall and white blood cells and phytohaemagglutinin (PHA) response indicative of cellular immunity were lowest in the summer among the four seasons, which supports the winter immunoenhancement hypothesis. IgG and IgM titers were lowest in the fall, which was against this hypothesis. Body fat mass had no correlations with cellular and humoral immunity, suggesting it was not the reason for seasonal changes in cellular and humoral immunity in males. Leptin titers were higher in spring and summer than in fall and winter. No correlation between leptin and cellular and humoral immunity suggested that leptin did not mediate their seasonal changes. Similarly, corticosterone levels were also higher in spring and summer than in fall and winter, which correlated negatively with cellular immunity but positively with IgG levels. This result implied that corticosterone has a suppressive effect on cellular immunity and an enhancing effect on humoral immunity. In summary, distinct components of immune systems exhibited different seasonal patterns. This article has an associated First Person interview with the first author of the paper.

Evaluation of the humoral immune response induced by vaccination for canine distemper and parvovirus: a pilot study

BACKGROUND

Canine Distemper Virus (CDV) and Canine Parvovirus (CPV) lead to infections with high mortality rates in dogs. These viruses affect unvaccinated dogs or dogs with incomplete vaccination protocols. Vaccination plays an important role in reducing death rates, preventing clinical cases and controlling the spread of virus However, the efficacy of vaccination might be affected by different factors including vaccine scheduling and the neutralization of the vaccine targets by maternal antibodies. In face of these factors, the main goals of this study are (i) to investigate the antibody responses of puppies undergoing different primary vaccination protocols against CPV and CDV and (ii) to estimate the time until seroreversion in adult dogs unvaccinated for at least 3 years.

RESULTS

Antibody protection against CDV and CPV was evaluated in a total of 20 dogs: 5 puppies that initiated immunization at 6 weeks after birth (group A), 8 animals that started vaccination between 8 and 12 weeks of age (group B), and 7 adult dogs that have not been vaccinated for at least 3 years (group C). Blood samples were collected from each animal, with 3 to 4 weeks apart. Antibody responses were measured using indirect ELISA. In the second immunization point, no significant differences were found between the seroconversion of groups A and B for each viral infection (p = 0.81 and 0.20 for CDV and CPV, respectively). In the third immunization, there was evidence for a shorter time to achieve a protective titer against CPV in group B when compared to group A (p = 0.015). Similar evidence was not found for CDV (p-value = 0.41). In Group C, the average time until seroveversion was estimated at 2.86 years and 7.63 years for CDV and CPV, respectively.

CONCLUSION

Vaccine response to CDV and CPV is specific in each individual. Effective immune protection in primary vaccination depends mainly on the initial titer of maternal antibodies acquired by the neonate. Other factors such as environmental exposure, immunization schedules and immune system activity influence the duration of immunity in adult dogs. The variability found reinforces the need to determine individual humoral immunity levels in order to assess vaccine efficacy.

PD-1 blockade augments humoral immunity through ICOS-mediated CD4+ T cell instruction

Successful applications of PD-1/PD-L1 blockade in multiple cancers highlight the efficacy of immunotherapy mediated by enhancing CD8⁺ T cell immunity both in mouse and human. How PD-1 blockade affects humoral immunity remains unclear. Herein we demonstrated that treatment of anti-PD-1 antibody led to the increase in both total IgG and OVA-specific IgG in OVA-immunized mice. However, no effect was observed on Ab affinity maturation. Accumulation of germinal center (GC) and memory B cells was observed in the spleens together with elevated percentages of plasma cells in the spleens and bone marrow. More interestingly, dramatic infiltration of CD4⁺ T cells was apparent in GCs after PD-1 blockade with a significant increase in the expression of ICOS. When CD4⁺ T cells and B cells from OVA-immunized mice were co-cultured with neutralizing anti-PD-1 Ab in vitro, PD-1 blockade recapitulated the up-regulation of ICOS expression on CD4⁺ T cells with the activation of ERK signaling. Suppression of ERK activation not only reduced ICOS expression on CD4⁺ T cells but also attenuated IgG production upon PD-1 blockade. Taken together, PD-1 blockade enhances humoral immunity. This process partially relies on more accumulation of CD4⁺ T cells in GCs with the up-regulation of ICOS expression and the promotion of B cell terminal differentiation. The regulatory pattern of PD-1 blockade illustrated here provides a new mechanism of how immune checkpoint molecules regulating humoral immune responses.

Evaluation of the humoral immune response induced by vaccination for canine distemper and parvovirus: a pilot study

BACKGROUND

Canine Distemper Virus (CDV) and Canine Parvovirus (CPV) lead to infections with high mortality rates in dogs. These viruses affect unvaccinated dogs or dogs with incomplete vaccination protocols. Vaccination plays an important role in reducing death rates, preventing clinical cases and controlling the spread of virus However, the efficacy of vaccination might be affected by different factors including vaccine scheduling and the neutralization of the vaccine targets by maternal antibodies. In face of these factors, the main goals of this study are (i) to investigate the antibody responses of puppies undergoing different primary vaccination protocols against CPV and CDV and (ii) to estimate the time until seroreversion in adult dogs unvaccinated for at least 3 years.

RESULTS

Antibody protection against CDV and CPV was evaluated in a total of 20 dogs: 5 puppies that initiated immunization at 6 weeks after birth (group A), 8 animals that started vaccination between 8 and 12 weeks of age (group B), and 7 adult dogs that have not been vaccinated for at least 3 years (group C). Blood samples were collected from each animal, with 3 to 4 weeks apart. Antibody responses were measured using indirect ELISA. In the second immunization point, no significant differences were found between the seroconversion of groups A and B for each viral infection (p = 0.81 and 0.20 for CDV and CPV, respectively). In the third immunization, there was evidence for a shorter time to achieve a protective titer against CPV in group B when compared to group A (p = 0.015). Similar evidence was not found for CDV (p-value = 0.41). In Group C, the average time until seroveversion was estimated at 2.86 years and 7.63 years for CDV and CPV, respectively.

CONCLUSION

Vaccine response to CDV and CPV is specific in each individual. Effective immune protection in primary vaccination depends mainly on the initial titer of maternal antibodies acquired by the neonate. Other factors such as environmental exposure, immunization schedules and immune system activity influence the duration of immunity in adult dogs. The variability found reinforces the need to determine individual humoral immunity levels in order to assess vaccine efficacy.

[Actualidades en la inmunopatología de la esclerosis múltiple]

Multiple sclerosis is a demyelinating inflammatory disease that affects the central nervous system. Its etiology is the result of a complex interaction between genetic and environmental factors that trigger a deregulated immune response, with the resulting inflammation and neuronal/axonal degeneration. Neuroinflammation is triggered when peripheral leukocytes migrate to the central nervous system and release cytokines such as interleukins 1 and 6 (IL-1 and 6) and tumor necrosis factor (TNF), which act on dwelling cells. The innate immune system plays an important role in the onset and progression of the disease by identifying molecular patterns associated with pathogens and damage, which modulate effector and regulatory functions of the cells where they are expressed, in order to direct the specific immune response. Th17 cells favor the disruption of the blood-brain barrier, which enables the migration of leukocytes to the central nervous system and the triggering of the inflammatory cascade; the Th1 profile (IL-1, IL-6) collaborates to perpetuate it. B-cell function is to produce antibodies and cytokines (IL-6, IL-12 and TFN). Knowledge on multiple sclerosis pathophysiology will enable the development of new therapeutic options that impact on natural history of the disease and its prognosis.

Generation of a novel Streptococcus agalactiae ghost vaccine and examination of its immunogenicity against virulent challenge in tilapia

Streptococcus agalactiae (S. agalactiae) is a gram-positive pathogen that causes a wide range of infections in fish and other animals including humans. Bacterial ghosts (BGs) are nonliving, empty cell envelopes and are well represented as novel vaccine candidates. In this study, we examined the immunogenicity and protective efficacy of S. agalactiae ghosts (SAG) against a virulent challenge in tilapia. Nonliving SAG was generated by a culture with Penicillin and Streptolysin, and then treated with the MIC of sodium hydroxide. The formation of a transmembrane lysis tunnel structure in SAG was visualized by electron microscopy. To investigate the SAG as a vaccine candidate, fish were divided into three groups, A (SAG immunized), B [Formalin-inactivated S. agalactiae (FSA) immunized] and C (phosphate-buffered saline, PBS-immunized control). The IgM antibody responses were significantly stronger in the SAG-immunized group than in FSA-immunized group, which was higher than in the non-immunized control group (P < 0.05). Moreover, phagocytic activity (percent phagocytes, PP) was significantly higher (p < 0.05) in the SAG-immunized group than in FSA-immunized group, which was higher than in the non-immunized control group (P < 0.05). In addition, non-specific immune immunity, such as lysozyme and superoxide dismutase activities, in the SAG-immunized fish showed significantly higher activities than FSA-immunized fish and the control group fish (P < 0.05). Also, fish immunized with SAG and FSA showed significantly higher (p < 0.05) gene expression of IL-1β, TNF-α, IFN-γ and TGF-β in the head kidney and spleen than fish treated with PBS during the whole observed period. In addition, fish immunized with SAG showed significantly higher gene expression of L-1β, TNF-α, and TGF-β in the spleen than in the FSA-immunized fish. Although there was no significant (P > 0.05) difference of survival rate (SR) or relative percent survival (RPS) between SAG and FSA immunized groups, they were all significantly more protected against the S. agalactiae challenge (SR: 86.67%, RPS: 76.395) and (SR: 80.00%, RPS: 67.50%) respectively, compared to the PBS-treated group (SR: 33.33%). These results suggest that immunization with SAG induces immune responses and provides protection against a virulent S. agalactiae challenge.

Deep analysis of immune response and metabolic signature in children with food protein induced enterocolitis to cow's milk

Background

Food Protein-Induced Enterocolitis Syndrome (FPIES) is considered to be a non-IgE mediated food allergy. However, its pathogenesis remains poorly understood and biomarkers are lacking. We aimed to perform in-depth characterization of humoral and cellular immune responses in children with cow’s milk (CM)-FPIES and investigated whether there is a FPIES metabolomic signature.

Methods

Children with CM-FPIES and control subjects with an IgE-mediated CM allergy (IgE-CMA), both avoiding CM, were recruited on the day of an oral food challenge. Blood samples were collected before the challenge. Total and specific levels of IgE, IgG1-4, IgA, IgM and IgD to various whey and casein allergens and to their gastroduodenal digestion products were measured in plasma, using plasma from CM-tolerant peanut allergic patients (IgE-PA, not avoiding CM) as additional controls. Cytokine secretion and cellular proliferation were analyzed after stimulation of PBMC with different CM allergens. Metabolomic profiles were obtained for plasma samples using liquid chromatography coupled to high-resolution mass spectrometry.

Results

Nine children with CM-FPIES and 12 control subjects (6 IgE-CMA and 6 IgE-PA) were included. In children with CM-FPIES, total Ig concentrations were lower than in control subjects, specific Ig against CM components were weak to undetectable, and no specific IgE against CM digestion products were detected. Moreover, in CM-FPIES patients, we did not find any Th cell proliferation or associated cytokine secretion after allergen reactivation, whereas such responses were clearly found in children with IgE-CMA. Plasma metabolic profiles were different between CM allergic patients, with significantly lower concentrations of various fatty acids and higher concentrations of primary metabolites such as amino acids in CM-FPIES compared to IgE-CMA patients.

Conclusions

In CM-FPIES, both humoral and cellular specific immune responses are weak or absent, and this is not related to CM avoidance. A metabolomic signature was identified in patients with CM-FPIES that may be useful for the diagnosis and management of this disease.

Electronic supplementary material

The online version of this article (10.1186/s13601-018-0224-9) contains supplementary material, which is available to authorized users.

Immunopotentiating effect of Inonotus obliquus fermentation products administered at vaccination in chickens

Vaccination is an important approach for the control of avian viral diseases. The aim of this study was to evaluate the immune-potentiating effect of oral administration of Inonotus obliquus fermentation products (IOFP) at vaccination in chickens. In total, 120 one-day-old specific-pathogen-free chickens were randomly assigned to six groups: groups 1 to 3 were vaccinated with Newcastle disease virus (NDV) LaSota live vaccine via intranasal and eye-dropped route at seven days of age, and boosted two weeks later. Before each immunization, chickens in groups 1 and 2 were orally administered 0.8% IOFP and 0.2% astragalus polysaccharide (APS) in their diets, respectively, for seven consecutive days and group 3 was fed with commercial diet. At the same time, group 4, 5 and 6 were inoculated in the same manner with PBS and fed with commercial diet, containing 0.8% IOFP and 0.2% APS diet, respectively, as negative controls. At 0, 7, 14, 21, 28, and 35 days post-inoculation (dpi) firstly, the temporal changes in serum Newcastle disease hemagglutination inhibition (HI) and neutralizing antibody titers were determined. Meanwhile, proliferations of peripheral blood mononuclear cells (PBMCs) isolated from each group in response to concanavalin A stimulation and the expression levels of Th1-type (IFN-γ) and Th2-type (IL-4) cytokines were determined by 3-(4,5-Dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide, and ELISA methods. On days 0, 14 and 28 after the first vaccination, the percentages of CD3⁺, CD3⁺CD8⁺, and CD3⁺CD4⁺ T lymphocytes were detected by flow cytometry. At 35 dpi, a challenge test was carried out and protective efficacy was determined. Results showed that oral administration of IOFP could significantly enhance ND HI and neutralizing antibody titers, proliferation of PBMCs, proportions of CD3⁺, CD3⁺CD8⁺, and CD3⁺CD4⁺ T lymphocytes, as well as the ratio of Th1/Th2, and all of these values were superior to those seen with APS as a positive control, and other groups. Therefore, IOFP possesses significant immune-potentiating properties in chickens and may be a more economical and convenient oral adjuvant to improve vaccination in avian species.

Different concentrations of Edwardsiella tarda ghost vaccine induces immune responses in vivo and protects Sparus macrocephalus against a homologous challenge

Bacterial ghosts (BGs) can be generated by the controlled expression of the PhiX174 lysis gene E in gram-negative bacteria. They are intriguing vaccine candidates since ghosts retain functional antigenic cellular determinants often lost during traditional inactivation procedures. Here we prepared Edwardsiella tarda ghost (ETG) and tested different concentrations in vaccination trials. The results showed that serum IgM antibody titers were significantly higher in three different concentration immunization groups than control group (P < 0.05), However, there was no significant (P > 0.05) difference between the immunized groups. The phagocytic percentage (PP) was significantly higher (P < 0.05) in ETG immunized groups than in the control group from 3 days post-treatment. The PP continued to rise with time until day 21, when the values of three ETG immunized groups were 45.7%,51.2% and 50.7%, respectively. In addition, phagocytic index (PI) was significantly higher (P < 0.05) in ETG immunized groups than in the control group after 7 days post-treatment. However, there was no significant (P > 0.05) difference of PP or PI between immunized groups. In addition, non-specific immune immunity, such as acid phosphatase, alkaline phosphatase, superoxide dismutase and lysozyme activities displayed a similar pattern in all immunized groups, all immunized fish showed significantly higher activities than control group fish (P < 0.05). Most importantly three ETG immunized groups were all significantly more protected against the E. tarda challenge (19/25, 76% survival), (21/25, 84% survival) and (20/25, 80% survival) respectively, compared to (9/25, 36% survival) survival in the control group, but there was no significant (P > 0.05) difference of survival rate (SR) or relative percent survival (RPS) between immunized groups. All these results suggest that an ETG could stimulate cellular and humoral immunity, and could be used as a vaccine candidate in S.m. In summary, ETG can protect fish from Edwardsiellosis, and there is no significant difference in SR and RPS when three different concentrations of ETG are used, so it can easily be developed as a vaccine for mechanical and artificial operations.

Clinical, laboratorial and immunological aspects of severe malaria in children from Guinea-Bissau

Malaria is a parasitic disease of which Plasmodium falciparum causes the most severe form of the disease. The immune response against Plasmodium spp. is complex and remains unclear. The present report aimed to better understand the humoral immune response in severe malaria and analyse new immunodominant antigen candidates as possible serological marker in severe malaria in children. This study included children aged 0-16 years from Guinea-Bissau with clinical signs of severe malaria. Serological and immunochemical characterisation of different anti-P. falciparum antibodies were made by ELISA and immunoblotting using a crude protein extract of P. falciparum. Sera from 12 children with severe malaria were analysed. Nine samples were positive for total anti-P. falciparum antibodies, seven for IgM and eight for total IgG anti-P. falciparum. There was a predominance of IgG1 response, suggesting a cytophilic action in severe malaria and a major role of IgG1 over other immunoglobulins. The antigenic profile of P. falciparum showed a consistent immunoblotting pattern of approximately 180 kDa, 100 kDa and around 50-40 kDa. The serological reactivity found in protein bands makes them as immunodominant antigens and promising candidates for serological markers in the context of severe malaria.