Antibody Response Research Articles

Antiretroviral Therapy with Ritonavir-Boosted Atazanavir- and Lopinavir-Containing Regimens Correlates with Diminished HIV-1 Neutralization.

The impact of virion maturation on neutralizing antibody responses in HIV treatment is not fully understood. This study examines whether antiretroviral regimens (ART) with boosted protease inhibitors (b-PI), which increase exposure to immature virions, affect neutralization capacity compared to Non-b-PI regimens. Neutralization activity was assessed in 45 HIV-infected individuals on b-PI regimens and 56 on Non-b-PI regimens, adjusting for factors like infection duration, ART initiation, and immune markers. Individuals on b-PI regimens had significantly lower neutralization scores [mean: 6.1, 95% Confidence Interval (CI): 5.3-6.9] than those on Non-b-PI regimens (mean: 8.9, 95% CI: 8.0-9.9; p < 0.0001). This difference was not explained by infection duration or CD4+ counts. CD4+/CD8+ ratios were positively associated with neutralization, while b-PI use was negatively associated. A regression model indicated that b-PI use significantly predicted lower neutralization scores (beta = -0.30, p = 0.049). These findings suggest that exposure to immature virions via b-PI use reduces neutralizing antibody responses, highlighting the importance of virion maturation in antibody induction. ART regimens promoting exposure to mature virions may enhance neutralization, with potential implications for HIV vaccine design. Further research is needed to explore implications for HIV vaccine design, especially using virus-like particles.

Adverse Impacts of PEGylated Protein Therapeutics: A Targeted Literature Review.

The beneficial effects of polyethylene glycol (PEG)-conjugated therapeutics, such as increased half-life, solubility, stability, and decreased immunogenicity, have been well described. There have been concerns, however, about adverse outcomes with their use, but understanding of those adverse outcomes is still relatively limited. The present study aimed to characterize adverse outcomes associated with PEGylation of protein-based therapeutics on immunogenicity, pharmacologic properties, and safety. A targeted review of English language articles published from 1990 to September 29, 2023, was conducted. Of the 29 studies included in this review, 18 reported adverse safety outcomes such as hematologic complications, hepatic toxicity, injection site reactions, arthralgia, nausea, infections, grade 3 or 4 adverse events (AEs), and AE-related discontinuations and dose modifications. Fifteen studies reported immunogenicity-related outcomes, such as the prevalence of pre-existing antibodies to PEG, treatment-emergent antibody response, and hypersensitivity reactions to PEGylated drugs. Seven studies reported pharmacological outcomes such as increased clearance and reduced activity in response to PEGylated drugs. This review aims to contribute to a balanced view of PEGylated therapies by summarizing the adverse outcomes or lack of benefit associated with PEGylated therapeutics reported in the literature. We identified several studies characterizing adverse outcomes, pharmacological effects, and immunogenicity associated with the use of PEGylated therapeutics. Our findings suggest that using PEGylated therapeutics may require careful monitoring for adverse safety outcomes, including screening and monitoring for pre-existing antibodies and those induced in response to PEGylated therapy, as well as monitoring and adjusting the dosing of PEGylated therapeutics.

Immunogenicity and Determinants of Antibody Response to the BNT162b2 mRNA Vaccine: A Longitudinal Study in a Cohort of People Living with HIV

Background: The COVID-19 pandemic posed significant challenges worldwide, with SARS-CoV-2 vaccines critical in reducing morbidity and mortality. This study evaluates the immunogenicity and antibody persistence of the BNT162b2 vaccine in people living with HIV (PLWH). Methods: We monitored anti-SARS-CoV-2 Spike IgG concentration in a cohort of PLWH at five time points (T0–T4) using chemiluminescent microparticle immunoassays (CMIAs) at the baselined both during and after vaccination. In severely immunocompromised individuals, a boosting dose was recommended, and participants and IgG concentration were measured in the two subgroups (boosted and not boosted). Results: In total, 165 PLWH were included, and 83% were male with a median age of 55 years (IQR: 47–62). At T1, 161 participants (97.6%) showed seroconversion with a median of IgG values of 468.8 AU/mL (IQR: 200.4–774.3 AU/mL). By T2, all subjects maintained a positive result, with the median anti-SARS-CoV-2 Spike IgG concentration increasing to 6191.6 AU/mL (IQR: 3666.7–10,800.8 AU/mL). At T3, all participants kept their antibody levels above the positivity threshold with a median of 1694.3 AU/mL (IQR: 926.3–2966.4 AU/mL). At T4, those without a booster dose exhibited a marked decrease to a median of 649.1 AU/mL (IQR: 425.5–1299.8 AU/mL), whereas those with a booster experienced a significant increase to a median of 13,105.2 AU/mL (IQR: 9187.5–18,552.1 AU/mL). The immune response was negatively influenced by the presence of dyslipidaemia at T1 (aOR 4.75, 95% CI: 1.39–16.20) and diabetes at T3 (aOR 7.11, 95% CI: 1.10–46.1), while the use of protease inhibitors (aORs 0.06, 95% CI: 0.01–0.91) and being female (aOR 0.02, 95% CI: 0.01–0.32) at T3 were protective factors. Conclusions: The immunogenicity of the BNT162b2 vaccine in PLWH has been confirmed, with booster doses necessary to maintain high levels of anti-SARS-CoV-2 Spike IgG antibodies, especially in patients with comorbidities. These findings underline the importance of a personalized vaccination strategy in this population.

Assessment of neutralizing antibody response as a correlate of protection against symptomatic SARS-CoV-2 infections after administration of two doses of the CoronaVac inactivated COVID-19 vaccine: A phase III randomized controlled trial

The emergence of variants of concerns of SARS-CoV-2 highlights the need for comprehensively elucidating the correlates of protection for different COVID-19 vaccine types. Inactivated COVID-19 vaccines are currently amongst the most widely administered vaccines globally. However, investigations into the correlates of protection for inactivated COVID-19 vaccines are relatively rare. Data from a phase III double-blind, randomized, placebo-controlled clinical trial (NCT0445659) that evaluated the efficacy and safety of the CoronaVac vaccine in healthcare professionals were utilized in this secondary analysis. Additionally, the correlation between neutralizing antibody levels measured by micro-cytopathic effect (CPE) neutralization assay and the occurrence of laboratory-confirmed infections was assessed using neutralizing antibodies measured in blood samples collected on day 28 after receiving two doses of the vaccine. Finally, the protective threshold required to provide 50% protection against symptomatic illness and virus infections was estimated. The risk of infection was negatively correlated with the levels of post-vaccination neutralizing antibodies measured on day 28 after the second dose. A neutralization titer of 30 (95% CI: 2-56) was predicted to provide 50% efficacy against symptomatic infection, whilst a titer of 42 (95% CI: 24-62) was predicted to provide 50% efficacy against total infection. Lastly, a neutralization titer of 247 (95% CI: 139-506) or higher was required to achieve 80% or higher protection against symptomatic infections. The results highlight the value of neutralizing antibody response as a correlate of protection, which can be used to inform future vaccine development and implementation. Further studies of immune correlates of protection for other vaccines are warranted.

Escherichia coli heat-labile enterotoxin B subunit as an adjuvant of mucosal immune combined with GCRV-II VP6 triggers innate immunity and enhances adaptive immune responses following oral vaccination of grass carp (Ctenopharyngodon idella)

The grass carp reovirus (GCRV) is the most major pathogen that has threatened the grass carp (Ctenopharyngodon idella) industry of China for years. Though the oral vaccine has many advantages, the current vaccines still do not provide complete protection. Therefor the exploration of new preventive strategies is urgently needed. In this study, heat-labile enterotoxin B subunit of Escherichia coli (LTB) was combined with VP6 from GCRV type II (GCRV-II) via Lactococcus lactis expression system to form a potent oral vaccine and determines if fusion of LTB to the protective vaccine antigen can enhance protection in the fish. The expression of recombinant protein was confirmed by Western-blotting and enzyme-linked immunosorbent assay. The rare minnow was set as the model for the evaluation of the experiment administrated orally. The immune response including the antibody titer and the immune-related gene expression, and the protective efficacy which included the virus loaded and the relative protection, were thoroughly investigated after the trial. The results indicated that LTB can significantly elicit a higher neutralizing antibody responses and enhanced T-cell priming, activities and proliferation in mononuclear cells from intestine, spleen and kidney tissues when compared to the VP6 vaccine alone. Moreover, the combined adjuvant can significantly up-regulate type I interferon signaling in different immune organs, especially the mucosa associated lymphoidtissue which could not be induced by VP6 along, result in the contribution of the improvement in adaptive immune responses of the fish. In addition, challenge study showed that LTB combined VP6 could greatly improve the relative percent survival of the fish during the virus infection. These results highlight that LTB has the potential value to be a mucosal adjuvant of the fish, approaching for improving the efficacy of vaccination against GCRV-II, which does elicit both non-specific and specific immune responses.

Health characteristics associated with persistence of SARS-CoV-2 antibody responses after repeated vaccinations in older persons over time: the Doetinchem cohort study

BackgroundOlder persons elicit heterogeneous antibody responses to vaccinations that generally are lower than those in younger, healthier individuals. As older age and certain comorbidities can influence these responses we aimed to identify health-related variables associated with antibody responses after repeated SARS-CoV-2 vaccinations and their persistence thereafter in SARS-CoV-2 infection-naïve and previously infected older persons.MethodIn a large longitudinal study of older persons of the general population 50 years and over, a sub-cohort of the longitudinal Doetinchem cohort study (n = 1374), we measured IgG antibody concentrations in serum to SARS-CoV-2 Spike protein (S1) and Nucleoprotein (N). Samples were taken following primary vaccination with BNT162b2 or AZD1222, pre- and post-vaccination with a third and fourth BNT162b2 or mRNA-1273 (Wuhan), and up to a year after a fifth BNT162b2 bivalent (Wuhan/Omicron BA.1) vaccine. Associations between persistence of antibody concentrations over time and age, sex, health characteristics including cardiometabolic and inflammatory diseases as well as a frailty index were tested using univariable and multivariable models.ResultsThe booster doses substantially increased anti-SARS-CoV-2 Spike S1 (S1) antibody concentrations in older persons against both the Wuhan and Omicron strains. Older age was associated with decreased antibody persistence both after the primary vaccination series and up to 1 year after the fifth vaccine dose. In infection-naïve persons the presence of inflammatory diseases was associated with an increased antibody response to the third vaccine dose (Beta = 1.53) but was also associated with reduced persistence over the 12 months following the fifth (bivalent) vaccine dose (Beta = -1.7). The presence of cardiometabolic disease was associated with reduced antibody persistence following the primary vaccination series (Beta = -1.11), but this was no longer observed after bivalent vaccination.ConclusionAlthough older persons with comorbidities such as inflammatory and cardiometabolic diseases responded well to SARS-CoV-2 booster vaccinations, they showed a reduced persistence of these responses. This might indicate that especially these more vulnerable older persons could benefit from repeated booster vaccinations.

Characterisation of the antibody-mediated selective pressure driving intra-host evolution of SARS-CoV-2 in prolonged infection.

Neutralising antibodies against the SARS-CoV-2 spike (S) protein are major determinants of protective immunity, though insufficient antibody responses may cause the emergence of escape mutants. We studied the humoral immune response causing intra-host evolution in a B-cell depleted, haemato-oncologic patient experiencing clinically severe, prolonged SARS-CoV-2 infection with a virus of lineage B.1.177.81. Following bamlanivimab treatment at an early stage of infection, the patient developed a bamlanivimab-resistant mutation, S:S494P. After five weeks of apparent genetic stability, the emergence of additional substitutions and deletions within the N-terminal domain (NTD) and the receptor binding domain (RBD) of S was observed. Notably, the composition and frequency of escape mutations changed in a short period with an unprecedented dynamic. The triple mutant S:Delta141-4 E484K S494P became dominant until virus elimination. Routine serology revealed no evidence of an antibody response in the patient. A detailed analysis of the variant-specific immune response by pseudotyped virus neutralisation test, surrogate virus neutralisation test, and immunoglobulin-capture enzyme immunoassay showed that the onset of an IgM-dominated antibody response coincided with the appearance of escape mutations. The formation of neutralising antibodies against S:Delta141-4 E484K S494P correlated with virus elimination. One year later, the patient experienced clinically mild re-infection with Omicron BA.1.18, which was treated with sotrovimab and resulted in an increase in Omicron-reactive antibodies. In conclusion, the onset of an IgM-dominated endogenous immune response in an immunocompromised patient coincided with the appearance of additional mutations in the NTD and RBD of S in a bamlanivimab-resistant virus. Although virus elimination was ultimately achieved, this humoral immune response escaped detection by routine diagnosis and created a situation temporarily favouring the rapid emergence of various antibody escape mutants with known epidemiological relevance.

A proteome-wide analysis unveils a core Epstein-Barr virus antibody signature of classic Hodgkin lymphoma across ethnically diverse populations.

Epstein-Barr virus (EBV) is an oncogenic virus associated with various malignancies, including classical Hodgkin lymphoma (cHL). Despite its known association, the specific role of humoral immune response to EBV remains poorly characterized in cHL. To address this, we conducted a study using a custom protein microarray to measure the antibody responses in cHL patients and matched healthy controls recruited from an East-Asian hospital-based case-control study. We identified 16 IgG antibodies significantly elevated in EBV-positive cHL compared with controls, defining an "East-Asian antibody signature of EBV-positive cHL." We evaluated responses against these 16 antibodies in a distinct European population, leveraging data from our previous European cHL case-control study from the UK, Denmark, and Sweden. A subset of antibodies (14/16, 87.5%) from the "East-Asian antibody signature of EBV-positive cHL" exhibited significant associations with cHL in the European population. Conversely, we assessed the "European antibody signature of EBV-positive cHL" identified in our prior study which consisted of 18 EBV antibodies (2 IgA, 16 IgG), in the East-Asian population. A subset of these antibodies (15/18, 83.3%) maintained significant associations with cHL in the East-Asian population. This cross-comparison of antibody signatures underscores the robust generalizability of EBV antibodies across populations. Five anti-EBV IgG antibodies (LMP-1, TK, BALF2, BDLF3, and BBLF1), found in both population-specific antibody signatures, represent a "core signature of EBV-positive cHL." Our findings suggest that the antibody responses targeting these core EBV proteins reflect a specific EBV gene expression pattern, serving as potential biomarkers for EBV-positive cHL independent of population-specific factors.

Discrimination of primary and chronic cytomegalovirus infection based on humoral immune profiles in pregnancy.

BACKGROUNDMost humans have been infected with cytomegalovirus (CMV) by midlife without clinical signs of disease. However, in settings in which the immune system is undeveloped or compromised, the virus is not adequately controlled and consequently presents a major infectious cause of both congenital disease during pregnancy as well as opportunistic infection in children and adults. With clear evidence that risk to the fetus varies with gestational age at the time of primary maternal infection, further research on humoral responses to primary CMV infection during pregnancy is needed.METHODSHere, systems serology tools were applied to characterize antibody responses to CMV infection in pregnant and nonpregnant women experiencing either primary or chronic infection.RESULTSWhereas strikingly different antibody profiles were observed depending on infection status, limited differences were associated with pregnancy status. Beyond known differences in IgM responses used clinically for identification of primary infection, distinctions observed in IgA and FcγR-binding antibodies and among antigen specificities accurately predicted infection status. Machine learning was used to define the transition from primary to chronic states and predict time since infection with high accuracy. Humoral responses diverged over time in an antigen-specific manner, with IgG3 responses toward tegument decreasing over time as typical of viral infections, while those directed to pentamer and glycoprotein B were lower during acute and greatest during chronic infection.CONCLUSIONIn sum, this work provides insights into the antibody response associated with CMV infection status in the context of pregnancy, revealing aspects of humoral immunity that have the potential to improve CMV diagnostics.FUNDINGCYMAF consortium and NIH NIAID.

Impact of Sex, Age and Body Habitus on RBD-specific Antibody Response After Two Doses of Sinopharm BBIBP-CorV Vaccine

Background: Mongolia started its nationwide vaccination campaign against COVID-19 on 23 February 2021 after receiving the first batch of the inactivated BBIBP-CorV. Age and body habitus of vaccinees may be associated with the immune effecter functions. Several systematic reviews and meta-analyses suggested lower immunogenicity of vaccines against SARS-CoV-2 infection in the older adult population and obese individuals. We aimed to establish a possible relationship between post-vaccine seroconversion rate and some biometric characteristics in the Mongolian cohort of vaccinees after two shots of the Sinopharm BBIBP-CorV vaccine. Materials and Methods: We collected serum samples from 846 eligible vaccinees before the first dose of the BBIBP-CorV vaccine and 21-28 days after the second dose of the same vaccine. Anti-SARS-CoV-2 Receptor Binding Domain (RBD) Immunoglobulin class G (IgG) and M (IgM) titer were measured in all samples. Results: 686 (81.1%) of 846 vaccinees received the Sinopharm BBIBP-CorV vaccine demonstrated seroconversion. Vaccinees with seroconversion had a younger mean age and lower mean body-mass index (BMI) than non-responders. Seroconversion rate according to age of vaccinees tends to decrease and obese vaccinees demonstrated a greater portion among non-responders. The Optimal Cut-Point (OCP) of age for seroconversion was found to differ significantly in male and female vaccinees. BMI has shown prediction ability for seroconversion only in male vaccinees but not in females. Using Receiver Operating Characteristics (ROC) analysis, we found 39 years for males and 41 years for females as a crucial milestone increasing the probability of seronegativity 2.5 times on average. A BMI higher than 29.1kg/m2 in male vaccinees was considered an acceptable predictor for seroconversion increasing the probability of seronegativity 2.4 times on average. Conclusion: The above findings allow us to summarize the sex-adjusted approach to biometric characteristics has an improved predictiveness for post-vaccine antibody response.

Enhancing preventive and therapeutic cancer vaccine efficacy through biotherapeutic ligand-associated extracellular vesicles

Extracellular vesicles (EVs), secreted by almost all living cells, have gained significant attention for their role in intercellular communication and their potential as versatile carriers for biotherapeutics. However, the clinical translation of EV-based therapies faces significant challenges, primarily due to the lack of efficient methods for loading biotherapeutic agents into EVs. This study introduces a simple, reproducible strategy for the simultaneous incorporation of various biotherapeutics within EVs. The process is gentle and preserves the essential physicochemical and biological characteristics of EVs, thereby protecting labile ligands from premature degradation and elimination. The binding and uptake efficiency of EVs by target cells reached approximately 97 % within 24 h of incubation. Administration of EVs loaded with oligodeoxynucleotides (ODN) resulted in a 4-fold increase in IFNγ+ CD4+ T cells and a 5-fold increase in IFNγ+ CD8+ T cells in the spleens and lymph nodes. Additionally, the co-administration of EVs with ODN and ovalbumin (OVA) induced elevated Th1-biased antibody responses and antigen-specific cytotoxic T-cell responses, providing long-lasting complete protection in 60 % of mice against T-cell thymoma challenge. Furthermore, EVs associated with three different ligands (OVA, CpG-ODN, and α-GalCer) effectively regressed established murine melanoma and significantly improved survival rates in mice. This study presents a powerful and promising approach to overcoming the limitations of EV-based cancer vaccines, advancing the development of effective cancer immunotherapies. SummaryImmunization with EVs that are co-associated with antigen and biotherapeutic cargo through a lyophilization-based technique elicits potent anti-cancer immunity.

Resolving Ambiguities in Deceased Donor HLA Typing: Next Generation Sequencing’s Role in DPB1 Allele Discrimination and Immunological Implications

Abstract HLA typing is crucial for assessing immunological compatibility between donors and recipients before transplantation. Deceased donor (DD) typing, typically via real-time PCR (rtPCR), provides rapid results vital for organ allocation. rtPCR primarily targets exons encoding the highly polymorphic peptide binding region (PBR) of HLA molecules. rtPCR cannot target all polymorphic sequences. Consequently, several possibilities of allele combinations are provided, leading to ambiguous typing results. As recent evidence suggests antibody responses can target regions in exons outside the PBR, notably in Exon 3 of the DPB1 locus, typing ambiguities can lead to the inability to assess histocompatibility between a donor and recipient. Herein, the aim was to investigate the utility of Next Generation Sequencing (NGS) in resolving DPB1 ambiguities in DD typing. A retrospective analysis of DD typing from February 2022 to January 2024 examined instances where NGS was used to resolve ambiguities reported via rtPCR. Each case was reviewed to understand the reason for resorting to NGS typing. The study focused on DPB1 ambiguities and assessed whether NGS effectively reduced ambiguity and differentiated alleles with polymorphisms outside the PBR. In total, 29 DD cases were found to have NGS testing results. In 14 cases, NGS was specifically performed to resolve DPB1 ambiguities. The ambiguities were significantly reduced from hundreds detected in rtPCR to 4 or fewer possible allele combinations with NGS. Eleven cases demonstrated polymorphism in exons outside the PBRs. Of these, only 2 cases showed no typing ambiguity with NGS. In the remaining 9 cases, though polymorphisms could be resolved in the PBR, ambiguities remained in exon 3, specifically at codon 96. In these cases, NGS could not distinguish lysine (K) from arginine (R). For example, DPB1*835:01 with the 96R motif could not be distinguished from DPB1*34:01with the 96K motif. The current investigation found that NGS cannot resolve all ambiguities at position 96, likely due, at least in part, to persistent cis-trans ambiguities. Our results suggest that although NGS drastically limited the number of ambiguities in 9 of 11 cases, it still could not adequately distinguish all immunologically relevant alleles. Inability to resolve the 96R/K epitope, which has been shown to be immunogenic, could impact solid organ transplantation, potentially leading to rejection in mismatched recipient-donor pairs at this position. Sequencing methods that generate longer reads, such as nanopore, may help resolve some of these cases if they are indeed due to cis-trans ambiguities.

Generation of Antibody Libraries for Phage Display: Human Fab Format.

Phage display is a powerful method for the de novo generation and affinity maturation of human monoclonal antibodies from naive, immune, and synthetic antibody repertoires. The pComb3 phagemid family of phage display vectors facilitates the selection of human monoclonal antibody libraries in the monovalent Fab format, which consists of human variable domains VH and VL (Vκ or Vλ), fused to the human constant domains CH1 of IgG1 and CL (Cκ or Cλ), respectively. Here, we describe the use of a pComb3 derivative, phagemid pC3C, for the generation of human Fab libraries with randomly combined human variable domains (VH, Vκ, and Vλ) of high sequence diversity, starting from the preparation of mononuclear cells from blood and bone marrow. Depending on the complexity of the parental antibody repertoire, the protocol can be scaled for yielding a library size of 108-1011 independent human Fab clones. As such, it can be used, for instance, for the generation of a large naive human Fab library from healthy individuals or for the generation of a specialized immune human Fab library from individuals with an endogenous antibody response of interest.

Tissue resident memory T cells contribute to protectionagainst heterologousSARS-CoV-2 challenge.

Widespread vaccination and natural infection have resulted in greatly decreased rates of severe disease, hospitalization and death after subsequent infection or reinfection with SARS-CoV-2. New vaccine formulations are based on circulating strains of virus, which have tended to evolve to more readily transmit human to human and to evade the neutralizing antibody response. An assumption of this approach is that ancestral strains of virus will not recur. Recurrence of these strains could be a problem for individuals not previously exposed to ancestral spike protein by vaccination or infection. Here, we addressed this question by infecting mice with recent SARS-CoV-2 variants and then challenging them with a highly pathogenic mouse-adapted virus closely related to the ancestral Wuhan-1 strain (SARS2-N501YMA30). We found that challenged mice were protected from death and substantial weight loss, even though they generally had low or no neutralizing antibody response to SARS2-N501YMA30 at the time of reinfection. T cell depletion from the previously infected mice did not diminish infection against clinical disease, although it did result in delayed kinetics of virus clearance in the nasal turbinate and in some cases, in the lungs. Levels of tissue resident memory T cells were significantly elevated in the nasal turbinate of previously infected mice compared to mice that had no previous exposure to SARS-CoV-2. However, this phenotype was not seen in lung tissues. Together, these results indicate that the immune response to newly circulating variants afforded protection against re-infection with the ancestral virus that was at least in part T cell based.

Kinetics of EBV antibody-based NPC risk scores in Taiwan NPC multiplex families.

Nasopharyngeal carcinoma (NPC) risk prediction models based on Epstein-Barr virus (EBV)-antibody testing have shown potential for screening of NPC; however, the long-term stability is unclear. Here, we investigated the kinetics of two EBV-antibody NPC risk scores within the Taiwan NPC Multiplex Family Study. Among 545 participants with multiple blood samples, we evaluated the stability of a 2-marker enzyme-linked immunosorbent assay score and 13-marker multiplex serology score using the intra-class correlation coefficient (ICC) by fitting a linear mixed model that accounted for the clustering effect of multiple measurements per subject and age. We also estimated the clustering of positive tests using Fleiss's kappa statistic. Over an average 20-year follow-up, the 2-marker score showed high stability over time, whereas the 13-marker score was more variable (p < .05). Case-control status is associated with the kinetics of the antibody response, with higher ICCs among cases. Positive tests were more likely to cluster within the same individual for the 2-marker score than the 13-marker score (p < .05). The 2-marker score had an increase in specificity from ~90% for single measurement to ~96% with repeat testing. The 13-marker score had a specificity of ~73% for a single measurement that increased to ~92% with repeat testing. Among individuals who developed NPC, none experienced score reversion. Our findings suggest that repeated testing could improve the specificity of NPC screening in high-risk NPC multiplex families. Further studies are required to determine the impact on sensitivity, establish optimal screening intervals, and generalize these findings to general population settings in high-risk regions.

Comparison of immunogenicity of adjuvanted and high dose influenza vaccination in long-term care facility residents.

The CDC recommends the more immunogenic adjuvanted and high-dose flu vaccines over standard-dose, non-adjuvanted vaccines for individuals above 65 years old. The current study compares adjuvanted trivalent inactivated flu vaccine (aTIV, FLUAD) versus high-dose flu vaccine (HD-IIV3, FLUZONE HD) to determine if they met non-inferiority standards for older long-term care facility (LTCF) residents. We collected blood from long-term care facility residents participating in a randomized 1:1 active control trial comparing MF59C.1 adjuvanted trivalent inactivated flu vaccine, aTIV versus HD-IIV3 over the course of two flu seasons, 2018-2019 and 2019-2020 (Trial, NCT03694808 ). We assessed humoral immunity at set time points via hemagglutinin inhibition assays (HAI) and anti-neuraminidase (enzyme-linked lectin assays (ELLA)). The recombinant influenza vaccine (RIV, Flublok) was assessed similarly in year two for a small number of participants who were carried over from year 1 (n=32). We enrolled 387 volunteers and administered either aTIV (n=194), HD-IIV3 (n=193) over the course of the 2018-2019 and 2019-2020 flu seasons. Among those enrolled and randomized in year one, a subset were administered RIV and studied in year two (n = 32). At 28 days post-vaccination, aTIV exhibited non-inferiority to HD-IIV3 for HAI for both H1N1 and H3N2 strains (GMT ratios (95% CI) for HD-IIV3/aTIV of 1.03(0.76, 1.4) and 1.04(0.73, 1.48), respectively; both 95% CI upper bounds < 1.5 to meet non-inferiority criteria) but not for Influenza B (GMT ratio (95% CI) = 1.21 (0.91, 1.61)). Non-inferiority criteria for HAI seroconversion were not met for any of the three strains. Applying the same non-inferiority criteria to neuraminidase inhibition (NI), both day 28 titer and seroconversion in aTIV were non-inferior to HD-IIV3 for H1N1 and H3N2 strains. Both aTIV and HD-IIV3 elicited similar immune responses with robust antibody responses. For the primary outcome, aTIV is non-inferior to HD-IIV3 for HAI titer of H1N1 and H3N2 but failed to meet non-inferiority criteria for Influenza B and seroconversion for all assessed strains. For the secondary outcome, aTIV was non-inferior to HD-IIV3 for both titer and seroconversion of anti-neuraminidase for both H1N1 and H3N2.

Association of Antibody Responses to Helicobacter pylori Proteins with Colorectal Adenoma and Colorectal Cancer.

Helicobacter pylori (H. pylori) has been implicated in colorectal carcinogenesis. Here, the association of immune responses to bacterial exposure with advancing stages of colorectal neoplasia was assessed by multiplex serology. Immunoglobulin (Ig) A and G antibody responses to thirteen proteins of H. pylori were measured by a Luminex-based multiplex assay in plasma from patients with colorectal cancer (CRC, n = 25), advanced adenoma (n = 82), or small polyps (n = 85) and controls (n = 100). Multivariable logistic regression was used to assess the association of bacterial seropositivity with colorectal neoplasia. The threshold for overall seropositivity required subjects to be positive for at least 4 out of the 13 tested antigens. In a cohort subset with matched data (n = 34), H. pylori seropositivity was correlated with bacterial abundance in both neoplastic and matched normal tissue. While no association was found between H. pylori seropositivity and the presence of CRC, IgA seropositivity to CagA was associated with a decreased risk of advanced adenoma (odds ratio, OR = 0.48, 95% confidence intervals, CIs: 0.24-0.96). Regarding IgG, higher antibody responses to HpaA was associated with advanced adenoma occurrence (OR = 2.46, 95% CI: 1.00-6.01), while responses to HP0395, CagA and Catalase were associated with polyp development (OR = 2.65, 95%, CI: 1.31-5.36, OR = 1.83, 95% CI: 1.01-3.32, and OR = 2.16, CI: 1.09-4.29, respectively). Positive correlations were found between H. pylori abundance in the normal mucosa and levels of both the IgA and IgG antibody response to Catalase and VacA antigens (r = 0.48, p < 0.01; r = 0.37, p = 0.04; r = 0.51, p < 0.01; and r = 0.71, p = 0.04, respectively). Conversely, H. pylori abundance was negatively correlated with levels of IgA antibody response to HpaA and with IgG antibody response to HP0231 in the diseased tissue (r = -0.34, p = 0.04 and r = -0.41, p = 0.01, respectively). The association between levels of H. pylori antigens and colorectal neoplasia risk gradually decreased with the adenoma progression, implicating the early activation of the immune response at the polyp stage. Thus, the evaluation of antibody response to certain bacterial antigens may indicate the presence of early-stage colorectal neoplasia. Further studies are needed to clarify the role H. pylori or the immune response to its antigens may have in colorectal carcinogenesis stages.

Induction of neutralizing antibody responses by AAV5-based vaccine for respiratory syncytial virus in mice.

Respiratory Syncytial Virus (RSV) is a significant cause of respiratory illnesses worldwide, particularly in infants and elderly individuals. Despite the burden RSV imposes, effective preventive measures are limited. The research application of adeno-associated virus (AAV) in vaccine platforms has been expanding, and its potential in prevention and treatment has garnered much attention. In this study, we explored the potential application of a recombinant adeno-associated virus 5 (rAAV5) vector-based RSV vaccine, focusing on the expression of the pre-fusion (Pre-F) protein structure. Through intramuscular immunization in mice. The immunogenicity of the vaccine was evaluated in Balb/c mice immunized intramuscularly and intranasal, respectively. The rAAV5-RSV-Fm vaccine demonstrated positive humoral and induced antibody titers against RSV strains A and B for up to 120 days post-immunization. Notably, intranasal administration also elicited protective antibodies. Characterization studies confirmed the ability of the vac-cine to express the Pre-F protein and its superior immunogenicity compared to that of full-length F protein. These findings underscore the potential application of rAAV5 vector platforms in RSV vaccine development and further investigation into their protective efficacy is warranted.

A novel orf virus vector-based COVID-19 booster vaccine shows cross-neutralizing activity in the absence of anti-vector neutralizing immunity

ABSTRACT Next-generation COVID-19 vaccines are being developed to expand the breadth of coverage against existing and future variants and to extend the duration of protection. Prime-2-CoV_Beta is an orf virus (ORFV) based multi-antigen COVID-19 vaccine that co-expresses Spike (S) and Nucleocapsid (N) antigens. The safety and immunogenicity of Prime-2-CoV_Beta is investigated in a phase 1 first-in-human (FIH) dose-finding trial (ORFEUS study, ClinicalTrials.gov: NCT05367843). Participants of two age groups (18–55 and 65–85 years) who previously completed at least two doses of mRNA vaccines were enrolled and sequentially assigned to different dose groups to receive one intramuscular dose of 3 × 105, 3 × 106, 1.5 × 107, or 3 × 107 plaque-forming units (PFU) of Prime-2-CoV_Beta on day 1 and a second dose on day 29. Here, we report safety and immunogenicity data collected up to 6 months after the first study vaccination. Prime-2-CoV_Beta is safe and well tolerated and elicits immune responses at higher dose levels in participants aged 18–55. A single dose of 3 × 107 PFU boosted binding and cross-neutralizing antibody responses that are maintained through 6 months after the first booster vaccination. Polyfunctional S-specific CD4+ and CD8+ T cell responses are observed after vaccination. No pre-existing or vaccine-induced neutralizing anti-vector antibodies are detected. Our findings highlight the potential of the ORFV vector as a safe platform for future vaccine design, which provides the ability to deliver multiple antigens and allows for repeat immunization.

A mathematical model simulating the adaptive immune response in various vaccines and vaccination strategies

Vaccination has been widely recognized as an effective measure for preventing infectious diseases. To facilitate quantitative research into the activation of adaptive immune responses in the human body by vaccines, it is important to develop an appropriate mathematical model, which can provide valuable guidance for vaccine development. In this study, we constructed a novel mathematical model to simulate the dynamics of antibody levels following vaccination, based on principles from immunology. Our model offers a concise and accurate representation of the kinetics of antibody response. We conducted a comparative analysis of antibody dynamics within the body after administering several common vaccines, including traditional inactivated vaccines, mRNA vaccines, and future attenuated vaccines based on defective interfering viral particles (DVG). Our findings suggest that booster shots play a crucial role in enhancing Immunoglobulin G (IgG) antibody levels, and we provide a detailed discussion on the advantages and disadvantages of different vaccine types. From a mathematical standpoint, our model proposes four essential approaches to guide vaccine design: enhancing antigenic T-cell immunogenicity, directing the production of high-affinity antibodies, reducing the rate of IgG decay, and lowering the peak level of vaccine antigen-antibody complexes. Our study contributes to the understanding of vaccine design and its application by explaining various phenomena and providing guidance in comprehending the interactions between antibodies and antigens during the immune process.