Humoral Research Articles

A prospective humoral immune monitoring study of kidney transplant recipients receiving three doses of SARS-CoV-2 mRNA vaccine.

Kidney transplant recipients (KTRs), like other solid organ transplant recipients display a suboptimal response to mRNA vaccines, with only about half achieving seroconversion after two doses. However, the effectiveness of a booster dose, particularly in generating neutralizing antibodies (NAbs), remains poorly understood, as most studies have mainly focused on non-neutralizing antibodies. Here, we have longitudinally assessed the humoral response to the SARS-CoV-2 mRNA vaccine in 40 KTRs over a year, examining changes in both anti-spike IgG and NAbs following a booster dose administered about 5 months post-second dose. We found a significant humoral response increase 5 months post-booster, a stark contrast to the attenuated response observed after the second dose. Of note, nearly a quarter of participants did not achieve protective plasma levels even after the booster dose. We also found that the higher estimated glomerular filtration rate (eGFR) correlated with a more robust humoral response postvaccination. Altogether, these findings underscore the effectiveness of the booster dose in enhancing durable humoral immunity in KTRs, as evidenced by the protective level of NAbs found in 65% of the patients 5 months post- booster, especially those with higher eGFR rates.

A chimeric haemagglutinin-based universal influenza virus vaccine boosts human cellular immune responses directed towards the conserved haemagglutinin stalk domain and the viral nucleoprotein

The development of a universal influenza virus vaccine, to protect against both seasonal and pandemic influenza A viruses, is a long-standing public health goal. The conserved stalk domain of haemagglutinin (HA) is a promising vaccine target. However, the stalk is immunosubdominant. As such, innovative approaches are required to elicit robust immunity against this domain. In a previously reported observer-blind, randomised placebo-controlled phase I trial (NCT03300050), immunisation regimens using chimeric HA (cHA)-based immunogens formulated as inactivated influenza vaccines (IIV)-/+ AS03 adjuvant, or live attenuated influenza vaccines (LAIV), elicited durable HA stalk-specific antibodies with broad reactivity. In this study, we sought to determine if these vaccines could also boost T cell responses against HA stalk, and nucleoprotein (NP). We measured interferon-γ (IFN-γ) responses by Enzyme-Linked ImmunoSpot (ELISpot) assay at baseline, seven days post-prime, pre-boost and seven days post-boost following heterologous prime:boost regimens of LAIV and/or adjuvanted/unadjuvanted IIV-cHA vaccines. Our findings demonstrate that immunisation with adjuvanted cHA-based IIVs boost HA stalk-specific and NP-specific T cell responses in humans. To date, it has been unclear if HA stalk-specific T cells can be boosted in humans by HA-stalk focused universal vaccines. Therefore, our study will provide valuable insights for the design of future studies to determine the precise role of HA stalk-specific T cells in broad protection. Considering that cHA-based vaccines also elicit stalk-specific antibodies, these data support the further clinical advancement of cHA-based universal influenza vaccine candidates. This study was funded in part by the Bill and Melinda Gates Foundation (BMGF).

Designing a Multi-epitope Vaccine against the SARS-CoV-2 Variant Based on an Immunoinformatics Approach.

SARS-CoV-2 is a life-threatening virus in the world. Scientific evidence indicates that this pathogen will emerge again in the future. Although the current vaccines have a pivotal role in the control of this pathogen, the emergence of new variants has a negative impact on their effectiveness. Therefore, it is urgent to consider the protective and safe vaccine against all sub-coronavirus species and variants based on the conserved region of the virus. Multi-epitope peptide vaccine (MEV), comprised of immune-dominant epitopes, is designed by immunoinformatic tools and it is a promising strategy against infectious diseases. Spike glycoprotein and nucleocapsid proteins from all coronavirus species and variants were aligned and the conserved region was selected. Antigenicity, toxicity, and allergenicity of epitopes were checked by a proper server. To robust the immunity of the multi-epitope vaccine, cholera toxin b (CTB) and three HTL epitopes of tetanus toxin fragment C (TTFrC) were linked at the N-terminal and C-terminal of the construct, respectively. Selected epitopes with MHC molecules and the designed vaccines with Toll-like receptors (TLR-2 and TLR-4) were docked and analyzed. The immunological and physicochemical properties of the designed vaccine were evaluated. The immune responses to the designed vaccine were simulated. Furthermore, molecular dynamic simulations were performed to study the stability and interaction of the MEV-TLRs complexes during simulation time by NAMD (Nanoscale molecular dynamic) software. Finally, the codon of the designed vaccine was optimized according to Saccharomyces boulardii. The conserved regions of spike glycoprotein and nucleocapsid protein were gathered. Then, safe and antigenic epitopes were selected. The population coverage of the designed vaccine was 74.83%. The instability index indicated that the designed multi-epitope was stable (38.61). The binding affinity of the designed vaccine to TLR2 and TLR4 was -11.4 and -11.1, respectively. The designed vaccine could induce humoral and cellular immunity. In silico analysis showed that the designed vaccine is a protective multi-epitope vaccine against SARS-CoV-2 variants.

Glaucoma and the Human Microbiome.

To explore a view of the human microbiome as an interconnected, functional, dynamic system that may be linked to the pathogenesis and progression of glaucoma. A literature review was undertaken that included publications from 1966 to 2023. Bacterial lipopolysaccharides (LPS) activate toll-like receptors (TLR) and mediate the human immune response. The LPS-TLR4 pathway is a potential avenue for the ocular, gut, and oral microbiomes to interface and/or influence ocular disease. Studies of gut dysbiosis have shown that alterations on the healthy microbiota can predispose the host to immune-mediated inflammatory and neurodegenerative conditions, while oral and ocular surface dysbiosis have been correlated with glaucoma. While developmental exposure to commensal microflora has shown to be necessary for the autoimmune and neurodegenerative responses to elevated intraocular pressure to take place, commensal bacterial products like short chain fatty acids have regulatory effects protective against glaucoma. Alterations to human microbiotas have been associated with changes in intestinal permeability, gene regulation, immune cell differentiation, and neural functioning, which may predispose the host to glaucoma. Select microbes have been highlighted for their potential contributions to glaucoma disease progression or protection, raising the potential for microbiota-based treatment modalities. Current topical glaucoma treatments may disrupt the ocular surface microbiota, potentially having ramifications on host health. Further study of the relationships between human microbiome and glaucoma is needed.

Role of autonomic nervous system in BDE-209 maternal exposure induced immunotoxicity in female offspring.

Decabrominated diphenyl ether (BDE-209) is a typical persistent organic pollutant that can cross the placental barrier, increasing the exposure risk for offspring. Norepinephrine (NE) from nerve terminals and acetylcholine (Ach) can bind to specific receptors on immune cells, inhibit the immune function of the body then cause immunotoxicity. However, whether maternal exposure to BDE-209 could lead to immunotoxicity in the offspring by acting on the sympathetic and parasympathetic nervous systems remains unclear. In view of this, the pregnancy and lactation rat BDE-209 exposure model was established and the results demonstrated that pregnancy and lactation BDE-209 exposure could induce immunotoxicity to female offspring via affecting immunopathology (hematological and biochemical parameters, organ indices, and spleen histopathological), decreasing humoral immunity (serum hemolysin, immunoglobulins, and cytokine productions), damaging cellular immunity (splenic lymphocytes and spleen cytokine productions), and restraining nonspecific immunity. Moreover, a dramatically significant correlation was observed between spleen nerve indices and immunity indices. Additionally, the mechanism revealed that maternal BDE-209 exposure caused offspring immunotoxicity through (1) activating MHC/PKCθ/NF-κB pathway; (2) promoting sympathetic nervous pathway, by upregulating the expression of β2AR protein, which in turn elevating cAMP, following activate PKA and phosphorylate CREB, ultimately leading to immunotoxicity;(3) activating parasympathetic nerve pathway by reducing the binding with Ach and α7nAchR, upregulating the expression of JAK2 and phosphorylating STAT3, induced immunotoxicity of female offspring.

Association between blood Pentraxin-3 concentrations and rheumatic diseases: A systematic review and meta-analysis.

Among the Pentraxins, the long Pentraxin-3 (PTX-3) is associated with several processes, particularly in the earliest phases of the innate humoral response. Increased blood PTX-3 concentrations have been observed in a wide range of conditions, from infectious to cardiovascular disorders. Since its increase is more rapid than C-reactive protein (CRP), PTX-3 can be useful to detect and monitor early inflammation. To dissect its pathophysiological role in rheumatic diseases (RD), we conducted a systematic review and meta-analysis comparing blood PTX-3 concentrations in RD patients and healthy individuals and investigating possible associations with clinical, demographic, and study characteristics. We performed a search of published evidence until April 2024 in PubMed, Web of Science and Scopus, which led to the selection of 60 relevant manuscripts from a total of 1072 records. Our synthesis revealed a statistically significant difference in PTX-3 concentrations between RD patients and controls (standard mean difference, SMD = 1.02, 95% CI 0.77-1.26, p < .001), that correlated with CRP concentrations. The effect size was associated with geographical region of study conduction, RD type, with a reduction of the observed heterogeneity in patients with low LDL-cholesterol and triglycerides concentrations. Our study has shown a significant increase in blood PTX-3 concentrations in RD patients, which was associated with specific patient characteristics. Nevertheless, additional studies are needed to better define the utility of measuring PTX-3 in the early phase of RD. Our study was conducted in compliance with the PRISMA 2020 statement (study protocol available at PROSPERO CRD42024516600).

Neutralizing antibody responses and cellular responses against SARS-CoV-2 Omicron subvariants after mRNA SARS-CoV-2 vaccination in kidney transplant recipients

Although the mRNA SARS-CoV-2 vaccine has improved the mortality rate in the general population, its efficacy against rapidly mutating virus strains, especially in kidney transplant recipients, remains unclear. We examined the anti-SARS-CoV-2 spike protein IgG antibody and neutralizing antibody titers and cellular immunity against B.1.1, BA.1, and BA.5 antigens in 73 uninfected kidney recipients and 16 uninfected healthy controls who received three doses of an mRNA SARS-CoV-2 vaccine. The IgG antibody titers were significantly lower in recipients than in healthy controls. Similarly, neutralizing antibody titers against three viral variants were significantly lower in recipients. When the virus was mutated, the neutralizing antibody titers decreased significantly in both groups. In cellular immunity analysis, the number of spike-specific CD8 + non-naïve T cells against three variants significantly decreased in recipients. Conversely, the frequency of spike-specific Th2 CD4 + T-cells in recipients was higher than that in healthy controls. Nineteen recipients and six healthy controls also received a bivalent omicron-containing booster vaccine, leading to increase IgG and neutralizing antibody titers in both groups. After that, eleven recipients and five healthy controls received XBB.1.5 monovalent vaccines, increasing the neutralizing antibody titers against not only XBB.1.5, but also EG.5.1 and BA.2.86 antigens in kidney recipients. Although kidney recipients did not gain sufficient immunity against Omicron BA.5 with the third dose of vaccine, humoral response against mutant SARS-CoV-2 lineages significantly increased after bivalent Omicron-containing booster vaccine and the XBB.1.5 monovalent vaccine. Therefore, it is important for kidney recipients to continue to administer updated vaccines.

Intranasal Immunization for Zika in a Pre-Clinical Model

Humans continue to be at risk from the Zika virus. Although there have been significant research advancements regarding Zika, the absence of a vaccine or approved treatment poses further challenges for healthcare providers. In this study, we developed a microparticulate Zika vaccine using an inactivated whole Zika virus as the antigen that can be administered pain-free via intranasal (IN) immunization. These microparticles (MP) were formulated using a double emulsion method developed by our lab. We explored a prime dose and two-booster-dose vaccination strategy using MPL-A® and Alhydrogel® as adjuvants to further stimulate the immune response. MPL-A® induces a Th1-mediated immune response and Alhydrogel® (alum) induces a Th2-mediated immune response. There was a high recovery yield of MPs, less than 5 µm in size, and particle charge of −19.42 ± 0.66 mV. IN immunization of Zika MP vaccine and the adjuvanted Zika MP vaccine showed a robust humoral response as indicated by several antibodies (IgA, IgM, and IgG) and several IgG subtypes (IgG1, IgG2a, and IgG3). Vaccine MP elicited a balance Th1- and Th2-mediated immune response. Immune organs, such as the spleen and lymph nodes, exhibited a significant increase in CD4+ helper and CD8+ cytotoxic T-cell cellular response in both vaccine groups. Zika MP vaccine and adjuvanted Zika MP vaccine displayed a robust memory response (CD27 and CD45R) in the spleen and lymph nodes. Adjuvanted vaccine-induced higher Zika-specific intracellular cytokines than the unadjuvanted vaccine. Our results suggest that more than one dose or multiple doses may be necessary to achieve necessary immunological responses. Compared to unvaccinated mice, the Zika vaccine MP and adjuvanted MP vaccine when administered via intranasal route demonstrated robust humoral, cellular, and memory responses. In this pre-clinical study, we established a pain-free microparticulate Zika vaccine that produced a significant immune response when administered intranasally.

The Impact of Time between Booster Doses on Humoral Immune Response in Solid Organ Transplant Recipients Vaccinated with BNT162b2 Vaccines

As solid organ transplant (SOT) recipients remain at risk of severe outcomes after SARS-CoV-2 infections, vaccination continues to be an important preventive measure. In SOT recipients previously vaccinated with at least three doses of BNT162b2, we investigated humoral responses to BNT162b2 booster doses. Anti-SARS-CoV-2 receptor binding domain (RBD) immunoglobulin G (IgG) was measured using an in-house ELISA. Linear mixed models were fitted to investigate the change in the geometric mean concentration (GMC) of anti-SARS-CoV-2 RBD IgG after vaccination in participants with intervals of more or less than six months between the last two doses of vaccine. We included 107 SOT recipients vaccinated with a BNT162b2 vaccine. In participants with an interval of more than six months between the last two vaccine doses, we found a 1.34-fold change in GMC per month (95% CI 1.25–1.44), while we found a 1.09-fold change in GMC per month (95% CI 0.89–1.34) in participants with an interval of less than six months between the last two vaccine doses, resulting in a rate ratio of 0.82 (95% CI 0.66 to 1.01, p = 0.063). In conclusion, the administration of identical COVID-19 mRNA vaccine boosters within six months to SOT recipients may result in limited humoral immunogenicity of the last dose.

Clouded judgments? The role of virtual weather in word valence evaluations

ABSTRACT Exploring the dynamic interface of environmental psychology and psycholinguistics, this investigation delves into how simulated weather conditions – sunny versus rainy – affect emotional perceptions of linguistic stimuli within a Virtual Reality (VR) framework. Participants assessed words’ emotional valence being exposed to these distinct environmental simulations. Contrary to expectations, we found that while rainy conditions modestly prolonged response times, they did not significantly alter the emotional valence attributed to words. Our study shows that weather can affect emotional cognition, but intrinsic emotional word properties are resilient to environmental influences. This highlights the complex interplay between environmental factors and linguistic processing and reaffirms the importance of environmental contexts in cognitive and emotional evaluations, especially in the face of climate change. By integrating VR technology with environmental psychology and linguistics, our research offers novel insights into the subtle yet significant ways in which virtual and real-world environments converge to shape human emotional and cognitive responses.

Interpretable deep learning reveals the role of an E-box motif in suppressing somatic hypermutation of AGCT motifs within human immunoglobulin variable regions

IntroductionSomatic hypermutation (SHM) of immunoglobulin variable (V) regions by activation induced deaminase (AID) is essential for robust, long-term humoral immunity against pathogen and vaccine antigens. AID mutates cytosines preferentially within WRCH motifs (where W=A or T, R=A or G and H=A, C or T). However, it has been consistently observed that the mutability of WRCH motifs varies substantially, with large variations in mutation frequency even between multiple occurrences of the same motif within a single V region. This has led to the notion that the immediate sequence context of WRCH motifs contributes to mutability. Recent studies have highlighted the potential role of local DNA sequence features in promoting mutagenesis of AGCT, a commonly mutated WRCH motif. Intriguingly, AGCT motifs closer to 5’ ends of V regions, within the framework 1 (FW1) sub-region1, mutate less frequently, suggesting an SHM-suppressing sequence context.MethodsHere, we systematically examined the basis of AGCT positional biases in human SHM datasets with DeepSHM, a machine-learning model designed to predict SHM patterns. This was combined with integrated gradients, an interpretability method, to interrogate the basis of DeepSHM predictions.ResultsDeepSHM predicted the observed positional differences in mutation frequencies at AGCT motifs with high accuracy. For the conserved, lowly mutating AGCT motifs in FW1, integrated gradients predicted a large negative contribution of 5’C and 3’G flanking residues, suggesting that a CAGCTG context in this location was suppressive for SHM. CAGCTG is the recognition motif for E-box transcription factors, including E2A, which has been implicated in SHM. Indeed, we found a strong, inverse relationship between E-box motif fidelity and mutation frequency. Moreover, E2A was found to associate with the V region locale in two human B cell lines. Finally, analysis of human SHM datasets revealed that naturally occurring mutations in the 3’G flanking residues, which effectively ablate the E-box motif, were associated with a significantly increased rate of AGCT mutation.DiscussionOur results suggest an antagonistic relationship between mutation frequency and the binding of E-box factors like E2A at specific AGCT motif contexts and, therefore, highlight a new, suppressive mechanism regulating local SHM patterns in human V regions.

A Nasal Vaccine Candidate, Containing Three Antigenic Regions from SARS-CoV-2, to Induce a Broader Response

A chimeric protein, formed by two fragments of the conserved nucleocapsid (N) and S2 proteins from SARS-CoV-2, was obtained as a recombinant construct in Escherichia coli. The N fragment belongs to the C-terminal domain whereas the S2 fragment spans the fibre structure in the post-fusion conformation of the spike protein. The resultant protein, named S2NDH, was able to form spherical particles of 10 nm, which forms aggregates upon mixture with the CpG ODN-39M. Both preparations were recognized by positive COVID-19 human sera. The S2NDH + ODN-39M formulation administered by the intranasal route resulted highly immunogenic in Balb/c mice. It induced cross-reactive anti-N humoral immunity in both sera and bronchoalveolar fluids, under a Th1 pattern. The cell-mediated immunity (CMI) was also broad, with positive response even against the N protein of SARS-CoV-1. However, neither neutralizing antibodies (NAb) nor CMI against the S2 region were obtained. As alternative, the RBD protein was included in the formulation as inducer of NAb. Upon evaluation in mice by the intranasal route, a clear adjuvant effect was detected for the S2NDH + ODN-39M preparation over RBD. High levels of NAb were induced against SARS-CoV-2 and SARS-CoV-1. The bivalent formulation S2NDH + ODN-39M + RBD, administered by the intranasal route, constitutes an attractive proposal as booster vaccine of sarbecovirus scope.

Timing of Assessment of Humoral and Cell-Mediated Immunity after Influenza Vaccination

Assessment of the immune response to influenza vaccines should include an assessment of both humoral and cell-mediated immunity. However, there is a lack of consensus regarding the timing of immunological assessment of humoral and cell-mediated immunity after vaccination. Therefore, we investigated the timing of immunological assessments after vaccination using markers of humoral and cell-mediated immunity. In the 2018/2019 influenza season, blood was collected from 29 healthy adults before and after vaccination with a quadrivalent inactivated influenza vaccine, and we performed serial measurements of humoral immunity (hemagglutination inhibition [HAI] and neutralizing antibody [NT]) and cell-mediated immunity (interferon-gamma [IFN-γ]). The HAI and NT titers before and after vaccination were strongly correlated, but no correlation was observed between the markers of cell-mediated and humoral immunity. The geometric mean titer and geometric mean concentration of humoral and cellular immune markers increased within 2 weeks after vaccination and had already declined by 8 weeks. This study suggests that the optimal time to assess the immune response is 2 weeks after vaccination. Appropriately timed immunological assessments can help ensure that vaccination is effective.

SARS-CoV-2 vaccination in the first year after hematopoietic cell transplant or chimeric antigen receptor T cell therapy: A prospective, multicenter, observational study.

The optimal timing of vaccination with SARS-CoV-2 vaccines after cellular therapy is incompletely understood. The objectives of this study are to determine whether humoral and cellular responses after SARS-CoV-2 vaccination differ if initiated <4 months versus 4-12 months after cellular therapy. We conducted a multicenter prospective observational study at 30 cancer centers in the United States. SARS-CoV-2 vaccination was administered as part of routine care. We obtained blood prior to and after vaccinations at up to five time points and tested for SARS-CoV-2 spike (anti-S) IgG in all participants and neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains, as well as SARS-CoV-2-specific T cell receptors (TCRs), in a subgroup. We enrolled 466 allogeneic hematopoietic cell transplant (HCT; n=231), autologous HCT (n=170), and chimeric antigen receptor T cell (CAR-T cell) therapy (n=65) recipients between April 2021 and June 2022. Humoral and cellular responses did not significantly differ among participants initiating vaccinations <4 months vs 4-12 months after cellular therapy. Anti-S IgG ≥2,500 U/mL was correlated with high neutralizing antibody titers and attained by the last time point in 70%, 69%, and 34% of allogeneic HCT, autologous HCT, and CAR-T cell recipients, respectively. SARS-CoV-2-specific T cell responses were attained in 57%, 83%, and 58%, respectively. Pre-cellular therapy SARS-CoV-2 infection or vaccination were key predictors of post-cellular therapy immunity. These data support mRNA SARS-CoV-2 vaccination prior to, and reinitiation three to four months after, cellular therapies with allogeneic HCT, autologous HCT, and CAR-T cell therapy.

Waning of Humoral Immunity to Vaccine-Preventable Diseases in Children Treated for Acute Lymphoblastic Leukemia: A Single-Center Retrospective Cross-Sectional Analysis.

The survival rates of children with acute lymphoblastic leukemia (ALL) have improved over the years, but infections remain a significant cause of morbidity and mortality. Chemotherapy has a range of harmful side effects including the loss of protective antibodies against vaccine-preventable diseases. The objective of this study was to evaluate the serological status of pediatric ALL cases before and after the intensive chemotherapy. Children treated and followed up for ALL at Dokuz Eylül University were included in this retrospective cross-sectional study. Antibody levels against hepatitis A, hepatitis B, and rubella were routinely assessed both at the time of diagnosis and six months after completion of chemotherapy. However, measles, mumps, and varicella antibody levels were evaluated just six months after the treatment. Seventy-eight children who completed chemotherapy for ALL were recruited. All participants had nonprotective antibody levels for at least one of the diseases. The highest seropositivity rate was found for hepatitis A (55.1%) and the lowest for measles (17.9%) after chemotherapy. Overall, 50.7%, 30.6%, and 45.7% of the patients significantly lost their humoral immunity against hepatitis B, hepatitis A, and rubella, respectively. Patients in the higher-risk group for ALL had a lower seropositivity rate than the other risk group patients. There were statistically significant relations between the protective antibody rates of hepatitis A and varicella and the age of the patients. Except for the hepatitis A vaccination, pre-chemotherapy vaccination did not affect post-chemotherapy serology. On the other hand, all children with a history of varicella before the diagnosis showed immunity after chemotherapy. All patients, including those previously fully vaccinated, are at great risk of infection due to the decrease in protective antibody levels after chemotherapy. There is a need for routine post-chemotherapy serologic testing and re-vaccination based on the results obtained.

REGRESSION OF SURVIVAL DAGUM 3 PARAMETER LINK FUNCTION IN HIV/AIDS PATIENTS IN EAST JAVA

AIDS (Acquired Immuno Deficiency Syndrome) is is a symptom of blood cell disease which results in decreased immunity in humans. HIV/AIDS causes a decline in economic productivity, health, and environmental fields, so it needs treatment to reduce the spread of the disease in East Java. The spread of the HIV/AIDS virus is growing rapidly both in terms of region and pattern of spread. Therefore, it is necessary to have policies from the government to prevent the spread of HIV/AIDS through mathematical modeling to determine the actual and comprehensive factors that influence HIV/AIDS care. policies needed to handle and reduce HIV/AIDS in East Java. This study aims to determine the factors that influence the care of people with HIV/AIDS with Survival Regression modeling Dagum 3 Parameter link function. This model uses parameter estimation with a Bayesian analysis approach with the results that the factors that significantly influence the length of HIV/AIDS care in East Java are marital status (X5), absolute CD4 levels (X7), Suffering Stage (X8), Functional State (X9), and Therapy adherence (X10). These results indicate that marital status and condition characteristics of HIV/AIDS sufferers are important information in the socialization program for reducing HIV/AIDS in East Java.

Sustained antigen delivery improves germinal center reaction and increases antibody responses in neonatal mice

Neonates and young infants are known to have limited responses to pediatric vaccines due to reduced germinal center formation. Extended vaccine antigen dosing was previously shown to expand germinal center formation and improve humoral responses in adult mice. We report that sustained antigen delivery through sequential dosing overcomes neonatal limitations to form germinal center reactions and improves humoral immunity. Thus, vaccine strategies that extend the release of vaccine antigens may reduce the number of doses, and time needed, to achieve protective immunity in neonates and young infants.

Avidity maturation of humoral response following primary and booster doses of BNT162b2 mRNA vaccine among nursing home residents and healthcare workers.

Infections, despite vaccination, can be clinically consequential for frail nursing home residents (NHR). Poor vaccine-induced antibody quality may add risk for such subsequent infections and more severe disease. We assessed antibody binding avidity, as a surrogate for antibody quality, among NHR and healthcare workers (HCW). We longitudinally sampled 112 NHR and 52 HCWs who received the BNT162b2 mRNA vaccine after each dose up to the Wuhan-BA.4/5-based Omicron bivalent boosters. We quantified anti-spike, anti-receptor binding domain (RBD), and avidity levels to the ancestral Wuhan, Delta, and Omicron BA.1 & 4/5 strains. The primary vaccination series produced substantial anti-spike and RBD levels which were low in avidity against all strains tested. Antibody avidity progressively increased in the 6-8months that followed. Avidity significantly increased after the 1st booster but not for subsequent boosters. This study underscores the importance of booster vaccination among NHR and HCWs. The 1st booster dose increases avidity, increasing vaccine-induced functional antibody. The higher cross-reactivity of higher avidity antibodies to other SARS-CoV-2 strains should translate to better protection from ever-evolving strains. Higher avidities may help explain how the vaccine's protective effects persist despite waning antibody titers after each vaccine dose.

Anti-HIV Humoral Response Induced by Different Anti-Idiotype Antibody Formats: An In Silico and In Vivo Approach

Despite advancements in vaccinology, there is currently no effective anti-HIV vaccine. One strategy under investigation is based on the identification of epitopes recognized by broadly neutralizing antibodies to include in vaccine preparation. Taking into account the benefits of anti-idiotype molecules and the diverse biological attributes of different antibody formats, our aim was to identify the most immunogenic antibody format. This format could serve as a foundational element for the development of an oligo-polyclonal anti-idiotype vaccine against HIV-1. For our investigation, we anchored our study on an established b12 anti-idiotype, referred to as P1, and proposed four distinct formats: two single chains and two minibodies, both in two different orientations. For a deeper characterization of these molecules, we used immunoinformatic tools and tested them on rabbits. Our studies have revealed that a particular minibody conformation, MbVHVL, emerges as the most promising candidate. It demonstrates a significant binding affinity with b12 and elicits a humoral anti-HIV-1 response in rabbits similar to the Fab format. This study marks the first instance where the minibody format has been shown to provoke a humoral response against a pathogen. Furthermore, this format presents biological advantages over the Fab format, including bivalency and being encoded by a monocistronic gene, making it better suited for the development of RNA-based vaccines.

Immunogenicity of a bivalent BA.1 COVID-19 booster vaccine in people with HIV in the Netherlands.

We evaluated the immunogenicity of a bivalent BA.1 COVID-19 booster vaccine in people with HIV (PWH). Prospective observational cohort study. PWH aged ≥45 years received Wuhan-BA.1 mRNA-1273.214 and those < 45 years Wuhan-BA.1 BNT162b2. Participants were propensity score-matched 1:2 to people without HIV (non-PWH) by age, primary vaccine platform (mRNA-based or vector-based), number of prior COVID-19 boosters and SARS-CoV-2 infections, and spike (S1)-specific antibodies on the day of booster administration. The primary endpoint was the geometric mean ratio (GMR) of ancestral S1-specific antibodies from day 0 to 28 in PWH compared to non-PWH. Secondary endpoints included humoral responses, T-cell responses, and cytokine responses up to 180 days post-vaccination. Forty PWH received mRNA-1273.214 (N = 35) or BNT162b2 (N = 5) following mRNA-based (N = 29) or vector-based (N = 11) primary vaccination. PWH were predominantly male (87% vs 26% of non-PWH) and median 57 years (interquartile range [IQR] 53-59). Their median CD4+ T-cell count was 775 (IQR 511-965) and the plasma HIV-RNA load was < 50 copies/mL in 39/40. The GMR of S1-specific antibodies by 28 days post-vaccination was comparable between PWH (4.48, 95% confidence interval [CI] 3.24-6.19) and non-PWH (4.07, 95% CI 3.42-4.83). S1-specific antibody responses were comparable between PWH and non-PWH up to 180 days, and T-cell responses up to 90 days post-vaccination. IFN-γ, IL-2, and IL-4 cytokine concentrations increased 28 days post-vaccination in PWH. A bivalent BA.1 booster vaccine was immunogenic in well-treated PWH, eliciting comparable humoral responses to non-PWH. However, T-cell responses waned faster after 90 days in PWH compared to non-PWH.