Association Between Severe SARS-CoV-2 Infection and De Novo HLA Donor Specific Antibody Production in Lung Transplant Recipients: Single-center study

Objectives: The COVID-19 pandemic has led to significant morbidity and mortality in lung transplant recipients (LTR). Respiratory viral infections may be associated with de-novo HLA donor-specific antibody (DSA) production and impact lung transplant outcome. Since one of the immunomodulation strategies post-SARS-CoV-2 infection in LTR include decreasing or holding anti-metabolites, concerns have been raised for higher incidence of de-novo DSA production in LTR. Method(s): We performed a retrospective chart review of 80 consecutive LTR diagnosed with COVID-19 to investigate this concern. COVID-19 disease severity was divided into 3 groups: mild, moderate, and severe. Mild disease was defined as patients with COVID-19 diagnosis who were stable enough to be treated as out-patients. Moderate disease was defined as patients who required admission to the hospital and were on less than 10 liters of oxygen at rest. Severe disease was identified as patients who required hospitalization and were on more than 10 liters of oxygen with or without mechanical ventilation or extra corporal membrane oxygenation (ECMO). Groups were compared using the Kruskal-Wallis test. Result(s): A total of 23, 47, and 10 LTR were diagnosed with mild, moderate, and severe COVID-19 respectively. De-novo HLA DSAwere detected in 0/23 (0%), 3/47 (6.3%), and 4/10 (40%) LTR with mild, moderate, and severe COVID-19 respectively (p = 0.0007) within 6 months post-COVID-19 diagnosis. Conclusion(s): Severe COVID-19 may be associated with increased risk of de novo HLA DSA production resulting in allograft dysfunction.Copyright © 2023 Elsevier Inc.

SARS-CoV2 infection after vaccination in patients requiring extracorporeal life support: An analysis from the EuroECMO-COVID study group

Objectives: At the beginning of the pandemic, it was believed that severe SARS-CoV2 infection would induce lifelong immunity and that reinfections would be unlikely. However, several cases of reinfection were documented in previously infected patient and the waning humoral immunity has raised significant concerns. Accordingly, long-term and durable vaccineinduce antibody protection against infection have also become a challenge, as several breakthroughs of COVID-19 have been identified in individuals partially or fully vaccinated. This study describes the incidence, the characteristics of severe COVID-19 infections requiring ECMO occurred after vaccination and the presence of side effects related to the vaccine. Method(s): EuroECMO COVID is a prospective, multicenter, observational study, developed by the EuroELSO, based on data from patients aged >=16 years who received ECMO support for refractory COVID-19 during the pandemic in 204 centers. The analysis investigates the survival of vaccinated patient, the associations between management-related variables, the incidence of vaccination during the different pandemic phases, the type of vaccines and the possible side effects. Result(s): Immunosuppressed patients are susceptible to reinfection even after being naturally infected or receiving a full vaccination. Ineffective antibody production, due to relatively ineffective vaccines, inadequate number of doses or the time after vaccination are involved in the pathogenesis of postvaccination infections. This population was found to have a partial immunity due to an inadequate number of doses and an overlapped time from vaccination and SARS-CoV2 incubation with PCR results after being vaccinated. Several manifestations of SARS-CoV2 infection are similar to vaccine-induce side effects and mild symptoms can be presented both as an adverse reaction after vaccination and a result of infection. In this subgroup no side effects were attributable to the vaccine. Conclusion(s): Vaccination does not entirely prevent SARS-CoV2 but will lead to less morbidity and mortality, as demonstrated by less need of ICU and ECMO care. In addition, the partial immunity for inadequate doses of vaccine or through the evolution of new variants demonstrated the importance of further analysis to differentiate the possible causes of waning humoral immunity.

Maternal and neonatal outcomes of Covid infections

SARS-CoV-2 was first detected in December 2019 and rapidly spread to become a pandemic. The disease associated with this infection (COVID-19) disproportionally affect pregnant people and their offspring, making them a high-risk group for morbidity and mortality. Infection with SARS-CoV-2 in pregnancy is associated with increased risk of progression to severe/critical disease and maternal death. It is also associated with adverse pregnancy outcomes including hypertensive disorders and prematurity. While vaccination is one of the most effective approaches to stem the COVID-19 pandemic, pregnant people were originally excluded from all randomized vaccine trials. Following studies examining the effects of COVID vaccine in pregnancy have focused on three general areas: maternal and fetal antibody production, short-term fetal safety, and overall pregnancy outcomes. In this presentation, we will summarize the COVID-19 disease phenotype in pregnancy, describe the association between COVID-19 and adverse pregnancy outcomes, and describe the safety and efficacy of COVID-19 therapeutics and vaccines in pregnancy.

A Promising Needle-Free Pyro-Drive Jet Injector for Augmentation of Immunity by Intradermal Injection as a Physical Adjuvant.

Current worldwide mRNA vaccination against SARS-CoV-2 by intramuscular injection using a needled syringe has greatly protected numerous people from COVID-19. An intramuscular injection is generally well tolerated, safer and easier to perform on a large scale, whereas the skin has the benefit of the presence of numerous immune cells, such as professional antigen-presenting dendritic cells. Therefore, intradermal injection is considered superior to intramuscular injection for the induction of protective immunity, but more proficiency is required for the injection. To improve these issues, several different types of more versatile jet injectors have been developed to deliver DNAs, proteins or drugs by high jet velocity through the skin without a needle. Among them, a new needle-free pyro-drive jet injector has a unique characteristic that utilizes gunpower as a mechanical driving force, in particular, bi-phasic pyrotechnics to provoke high jet velocity and consequently the wide dispersion of the injected DNA solution in the skin. A significant amount of evidence has revealed that it is highly effective as a vaccinating tool to induce potent protective cellular and humoral immunity against cancers and infectious diseases. This is presumably explained by the fact that shear stress generated by the high jet velocity facilitates the uptake of DNA in the cells and, consequently, its protein expression. The shear stress also possibly elicits danger signals which, together with the plasmid DNA, subsequently induces the activation of innate immunity including dendritic cell maturation, leading to the establishment of adaptive immunity. This review summarizes the recent advances in needle-free jet injectors to augment the cellular and humoral immunity by intradermal injection and the possible mechanism of action.

Method for Quantitative Assessment of Protective Immunity against Sars-Cov-2, Its Duration and Antibody Dynamics

The level and duration of protective immunity are often analyzed qualitatively or semi-quantitatively. The same strategy is applied to the analysis of antibody dynamics. At some point in time t after exposure or immunization, the presence of immunity against the infection is inferred from the level of specific antibodies by comparing it to a reference value. This approach does not account for the stochastic nature of human disease after exposure to a pathogen. At the same time, it is not fully clear what antibody level should be considered protective. The aim of this study was to develop a mathematical model for quantitative determination of protective immunity against SARS-CoV-2 and its duration. We demonstrate that the problem of describing protective immunity in quantitative terms can be broken down into 2 interrelated problems: describing the quantitative characteristics of a pathogen's virulence (in our case, the pathogen is SARS-CoV-2) and describing the dynamics of antibody titers in a biological organism. Below, we provide solutions for these problems and identify parameters of the model which describes such dynamics. Using the proposed model, we offer a theoretical solution to the problem of protective immunity and its duration. We also note that in order to quantitatively determine the studied parameters in a homogenous population group, it is necessary to know 5 parameters of the bivariate probability density function for correlated continuous random variables: the infective dose of the pathogen and the antibody titer at which the disease develops and which are still unknown.Copyright © Extreme Medicine.All right reserved.

IMMUNOGENICITY OF SARS-CoV-2 mRNA VACCINATION IN IDIOPATHIC CD4 LYMPHOPENIA

Background: The rapid development of SARS-CoV-2 mRNA vaccines has been a remarkable success of the COVID-19 pandemic, but vaccine-induced immunity is heterogeneous in immunocompromised populations. We sought to determine the immunogenicity of SARS-CoV-2 mRNA vaccines in a cohort of people with idiopathic CD4 lymphopenia (ICL). Method(s): 25-patients with ICL followed at the National Institutes of Health on a natural history protocol were evaluated between 2020-2022. Blood and serum was collected within 4-12 weeks after their second and/or third SARS-CoV-2 mRNA vaccine dose. Twenty-three matched healthy volunteers (HVs) provided blood samples at similar timepoints post-mRNA vaccination on a separate clinical protocol. Pre-vaccine blood samples were also used when available. Anti-spike and anti-receptor binding domain antibodies were measured. T-cell stimulation assays were performed to quantify SARS-CoV-2 specific T-cell responses. Comparisons were made with Wilcoxon test. Result(s): Twenty-participants with ICL had samples collected after their second mRNA vaccine and 7-individuals after the third dose. Median age at vaccination was 51-years (IQR: 44-62) and 12 were women (48%). Median CD4 T-cell count was 150 cells/muL (IQR: 85-188) at the time of vaccination, and 11-individuals (44%) had a baseline CD4 count <=100 cells/muL. HVs had a median age of 54-years (IQR: 43-60) with 13-women (56.5%). Anti-spike IgG antibody levels were significantly greater in HVs than those with ICL after 2-doses. Lower SARS-CoV-2 IgG antibody production was primarily observed in those with baseline CD4 T-cells <=100 cells/mul (Figure-1A). The decreased production in ICL remained after a third vaccine dose (Figure-1B). There was a significant correlation between anti-spike IgG and baseline CD4 count. Spike-specific CD4 T-cell responses in volunteers compared to those with ICL demonstrated similar levels of activation induced markers (CD154+CD69+) and cytokine production (IFNgamma+, TNFalpha+, IL2+) after two or three mRNA vaccine doses. Quantitatively the smallest responses were observed in those with lower baseline CD4 T-cells (Figure 1C-D). Minimal SARS-CoV-2 CD8 T-cell responses were detected in both groups. Conclusion(s): Patients with ICL and baseline CD4 T-cells >100 mount similar humoral and cellular immune responses to SARS-CoV-2 vaccination as healthy volunteers. Those with baseline CD4 T-cells <=100 have impaired vaccine- induced immunity and should be prioritized to additional boosters and continue other risk mitigation strategies. (Figure Presented).

Development of a Lymphoid Organ-Chip to Evaluate Covid Vaccine Boosting Strategies

Background: Secondary lymphoid organs provide the adequate microenvironment for the development of antigen (Ag)-specific immune responses. The tight collaboration between CD4+ T cells and B cells in germinal centers is crucial to shape B cell fate and optimize antibody maturation. Dissecting these immune interactions remains challenging in humans, and animal models do not always recapitulate human physiology. To address this issue, we developed an in vitro 3D model of a human lymphoid organ. The model relies on a microfluidic device, enabling primary human cells to self-organize in an extracellular matrix (ECM) under continuous fluid perfusion. We applied this Lymphoid Organ-Chip (LO chip) system to the analysis of B cell recall responses to SARS-CoV-2 antigens. Method(s): We used a two-channel microfluidic Chip S1 from Emulate, where the top channel is perfused with antigen (spike protein or SARS-CoV-2 mRNA vaccine), while the bottom channel contains PBMC (n = 14 independent donors) seeded at high-density in a collagen-based ECM. Immune cell division and cluster formation were monitored by confocal imaging, plasmablast differentiation and spike-specific B cell amplification by flow cytometry, antibody secretion by a cell-based binding assay (S-flow). Result(s): Chip perfusion with the SARS-CoV-2 spike protein for 6 days resulted in the induction CD38hiCD27hi plasmablast maturation compared to an irrelevant BSA protein (P< 0.0001). Using fluorescent spike as a probe, we observed a strong amplification of spike-specific B cell (from 3.7 to 140-fold increase). In line with this rapid memory B cell response, spike-specific antibodies production could be detected as early as day 6 of culture. Spike perfusion also induced CD4+ T cell activation (CD38+ ICOS+), which correlated with the level of B cell maturation. The magnitude of specific B cell amplification in the LO chip was higher than in 2D and 3D static cultures at day 6, showing the added value of 3D perfused culture for the induction of recall responses. Interestingly, the perfusion of mRNA-based SARS-CoV-2 vaccines also led to strong B cell maturation and specific B cell amplification, indicating that mRNA-derived spike could be expressed and efficiently presented in the LO chip. Conclusion(s): We developed a versatile Lymphoid Organ-Chip model suitable for the rapid evaluation of B cell recall responses. The model is responsive to protein and mRNA-encoded antigens, highlighting its potential in the evaluation of SARS-CoV-2 vaccine boosting strategies.

AUTOPHAGY AND Acyl-CoA-BINDING PROTEIN INFLUENCE COVID-19 SEVERITY

Background: Autophagy, a cytosolic-structure degradation pathway, allows production of IL21 by CD4 T-cells and efficient cytolytic responses by CD8 T-cells. Autophagy is in part regulated by acyl-CoA-binding protein (ACBP) which has two functions. Intracellular ACBP favors autophagy, whereas secreted extracellular ACBP inhibits autophagy. Herein, we assessed whether autophagy and the ACBP pathway were associated with COVID-19 severity. Method(s): Through the BQC-19 Quebec biobank, somalogic proteomic analysis was performed on 5200 proteins in plasma samples collected between March 2020 and December 2021. Plasma from 903 patients (all data available) during the acute phase of COVID-19 were assessed. COVID-19 severity was stratified using WHO criteria. In vitro, ACBP intracellular levels, autophagy levels (LC3II) and IL21 production were assessed by flow in PBMCs after a 24h stimulation with IL6, phorbol myristate acetate (PMA)+ionomycin or lipopolysaccharide (LPS). Plasma levels of anti-SARS-CoV-2 (full spike protein or RBD) IgG were assessed by ELISA. Result(s): Median age of the cohort was 62 yo, 48% were female, 55% had comorbidities (see table). Increasing plasma levels of ACBP were found with severity (mild, moderate, severe and fatal groups having 5.3, 7.3, 9.5 and 10.6 RFU/50muL of plasma, respectively, p< 0.001 for all comparisons). Patients with comorbidities had higher plasma ACBP levels (7.4 vs 6.4 RFU/50muL, p< 0.001). Plasma ACBP levels were higher during the delta and omicron-variant periods (8.4 vs 6.8 RFU/50muL;p< 0.001). Plasma ACBP levels correlated with LC3II levels (r=0.51, P< 0.001) and IL6 (r=0.41, p< 0.001), but neither with markers IL1beta nor IL8. ACBP levels negatively correlated with IL21 levels (r=-0.27, p< 0.001), independently of age, sex, and severity. ACBP levels were not associated with levels of anti-SARS-CoV-2 IgG levels. In vitro, IL6 stimulation of healthy control PBMC induced extracellular ACBP release. Moreover, adding recombinant ACBP: 1) reduced autophagy in lymphocytes and monocytes upon polyclonal stimulation with PMA/ionomycin or LPS;2) reduced intracellular production of IL21 in T-cells after PMA/ ionomycin stimulation. Conclusion(s): Plasma ACBP levels were inversely linked with IL21 levels, suggesting that autophagy and IL21 allow control of SARS-CoV-2 infection, independently of the level of SARS-CoV-2 antibody secretion. ACBP is a targetable autophagy checkpoint and its extracellular inhibition may improve SARS-CoV-2 immune control. (Table Presented).

Humoral response against SARS-CoV-2 and other endemic corona viruses

In a study of two Hospitals in Saxony (Chemnitz and Leipzig), we analyzed the antibody development towards SARS-CoV-2 and against a variety of endemic coronaviruses. Here we analyzed 760 sera from a Saxonian cohort for antibody reactivity against: Common cold coronaviruses, HCoV-229E, HCoV-HKU 1, HCoV-NL63 and HCoV-OC43, MERS-CoV and SARS-CoV. For the SARS CoV-2 immune response we tested the following antigens: Spike, S1, S2, RBD and nucleocapsid. These 11 antigen determinants were tested in a commercial multiplex Luminex based assay. We tested sera from 544 individuals (347 females and 197 males;498 SARS-CoV-2 PCR positive and 262 SARS-CoV-2 PCR negative) between May 2020 and March 2022. We observed up to 10% reactivity against the MERS virus in both the PCR positive and negative group. Against the common cold corona viruses 80%-90 % of the individuals in both groups show detectable antibodies. Regarding the antibody response against SARS-CoV a significant difference was observe. Only 19% of COVID-19 infected individuals show antibodies against the virus, while 81% of the PCR-positive individuals produced antibodies. The presence of antibodies against the SARS-CoV-2 is positively correlated with those against SARS-CoV (p = 0.001). No changes in endemic antibody responses were see in the two groups. The antibody status after first immunization event (infection/ vaccination) shows differences in nucleocapsiddirected antibody production, found in the natural infection group (about 60%). In the vaccination group, more individuals (up to 95%) show an immune response against Spike, S1 and RBD compare with natural infection. In summary, the examined cohort shows a general immunization up to 90% against most endemic corona viruses. Correlation analyses show cross-reactivity between SARS-CoV-2 and SARS-CoV. Longitudinal antibody analyses are under way, as also correlations of humoral response with immunogenetic factors.

Seroconversion in nasal lining fluid antibodies after Covid19 infection in a health professional cohort

Background: The novel coronavirus SARS-CoV- 2 has caused far-reaching consequences world-wide. Lack of immunity in human, severe airway disease based on a high virulence and its airborne transmission pointed to a significant role of the airways. To investigate immune responses and antibody seroconversion in nasal lining fluid and in serum we examined a cohort of health professionals at the university hospital Klinikum rechts der Isar in Munich. By long-term follow-up of infected and non-infected participants, we were able to investigate the development of local and systemic immunity against SARS-CoV- 2. Method(s): To learn about nasal antibody production we reached out for hospital staff with estimated high risk of a possible Covid19 infection due to their working conditions and staff members suffering from symptoms like fever, cough, loss of smell and taste or sore throat. To detect current infections, we performed SARS-CoV- 2 PCR testing at visit one (V1) and asked our participants to rate possible Covid19 symptoms by filling a questionnaire before every sampling. We eventually included participants, who had been tested positive for SARS-CoV- 2 before (n = 22), as well as people without detected infection, including high-risk contact persons of Covid19 patients and individuals with no Covid-19 infection so far (n = 85). The cohort included 107 hospital staff members, who were sampled six times overall between March and September 2020. Each of the six visits V1 -V6 contained the sampling of serum and nasal fluid to measure IgG, IgM, and IgA rates using immunoassay technique. Result(s): We were able to show the increase of IgA and IgG in the nasal mucosa after recent Covid19 infection. In infected individuals the levels of SARS-CoV- 2 specific nasal IgA increased until V2 with a mean of 4,81 +/- 1,92 mug/l compared to a mean of 0,13 mug/l in non-infected participants, followed by a plateau until V4 and decreased again until V6. Nasal IgG showed a similar trend, apart from a steeper decline after reaching a peak on V2 with a mean of 7,39 +/- 1,63 mug/l, which correlated to the antibody responses in serum. Non-infected individuals showed a mean level of 0,03 mug/l nasal IgG on V2. Serum IgA declined from V1 onwards and hereby showed a quicker drop of systemic antibody levels compared to the nasal lining fluid. Nasal antibody rates reached peaks of 40,00 mug/l (nasal IgA) and 25,74 mug/l (nasal IgG). However, these counts will need further confirmation by a vaccinated control group. Conclusion(s): Nasal measurement of SARS-CoV- 2 specific antibodies provides deeper understanding of mucosal processes while facing inflammation, which may pave the way to less invasive diagnostic possibilities in the future. Furthermore, nasal antibodies built-up after an infection with Covid19 may be protective features concerning a possible re-infection with the virus.

Immunogenicity, safety and efficacy in the CVID patients -Data from the 6-month prospective study

Background: A single-stranded mRNA virus SARS-CoV- 2 is associated with severe acute respiratory syndrome in the predisposed individuals such as elderly, obese, chronic cardiovascular or pulmonary diseases. Higher risk for severe course was also reported in inborn errors of immunity (IEI). While restriction measures play important role from the short-term perspective, vaccination may provide long-term protection. However, only limited data are available on safety and efficacy in immunocompromised patients with IEI such as Common variable immunodeficiency (CVID). Method(s): We assessed humoral and cellular responses, safety and efficacy in a cohort of 20 CVID patients after 2 doses of anti-SARS- CoV- 2 vaccine BNT162b. The humoral reponse was evaluated using ELISA and western blot methods, the T cell response measured by IFNg secretion functional assay. Adverse events were reported by Patient Clinical Questionnaire. Blood count, biochemical, coagulation and immunological parameters were checked before and after vaccination. The patients were followed for 6 months. Result(s): Despite severely impaired antibody production hunoral response was detected in 48% (n = 10/21) of patients at month 1. However, the response persisted in only 33% (n = 6/18) at month 3 and further decreaed to 13% (n = 2/15) at month 6. The T cell response was measurable in 5 patients (28%) at month 1. In total, 4 out of 20 (20%) patients got infected within the study period. None of them required oxygenotherapy or hospital admission. We did not observe any severe adverse effects beyond local pain, fatigue, headche, fever, arthralgia and myalgia. Conclusion(s): Vaccination with mRNA vaccine BNT162b provides safe and effective protection for a subgroup of CVID patients. However, the immunogenicity is lower compared to the general population.

Higher pro-inflammatory cytokines are associated with anti-SARS-CoV-2 spike protein-specific seroconversion after two doses of COVAXINTM, COVISHIELDTM vaccination in renal transplant recipients

Introduction: Generating adequate cellular and humoral responses are essential principle of vaccination. Immune system of renal transplant recipient remained compromised and speculated to less likely to develop antibody after vaccination. SARS-CoV-2 neutralizing antibody after anti-SARS-CoV-2 vaccination is required for the protection from subsequent viral infection. During COVID-19 disease, anti-SARS-CoV-2 specific antibody formation was correlated with the inflammatory cytokines level. Although, there is limited informations about serum cytokines and antibody formation after COVAXINTM, COVISHIELDTM vaccination in RTRs. Therefore, in the current study, we have evaluated the inflammatory cytokines response and anti-SARS-CoV-2 specific antibody formation in renal transplant recipient. Method(s): In this study, we have recruited 171 live-related renal transplant recipients vaccinated with two doses of either COVAXINTM (whole inactivated virus-based vaccine) or COVISHIELDTM (Simian adenovirus containing full-length spike protein-based vaccine). A 5 ml blood sample was collected after two weeks of 2nd dose of vaccination. The serum was separated and stored at -200C till the analysis. Anti-SARS-CoV-2 spike protein-specific IgG antibody titer was determined by chemiluminescent microparticle immunoassay methods and Cytokines IL-10, TGF-beta, IFN-gamma, IL-6 were measured by the ELISA techniques. Result(s): The overall anti-SARS-CoV-2 spike protein specific seroconversion after vaccination was observed in 149/171(87.13%) of RTRs with median IgG titer in seroconversion group 1191.90 (IQR, 398.70-2652.45) au/ml. The median and interquartile serum cytokines IL-10 level in seroconversion (n=149) vs non-seroconversion (n=22) group was 88.89 (IQR, 55.5-125.92) vs 92.59 (IQR, 48.14-148.14) pg/ml. The median TGF-beta level in seroconversion vs non-seroconversion group was 692.10 (IQR, 446.05-927.63) vs 1001.31 (IQR, 813.15-1125.65) pg/ml. The median IL-6 level in seroconversion vs non-seroconversion group was 46.66 (33.3-66.66) vs 28.33 (16.66-34.16) pg/ml. The median IFN-gamma level in seroconversion vs non-seroconversion group was 98.0 (IQR, 57.40-111.60) vs 50.0 (IQR, 30.55-52.55) pg/ml. The cytokines IL-6 and IFN-gamma level was positively correlated with anti-SARS-CoV-2 specific protein antibody titer (r=0.192;p=0.012), IFN-gamma (r=0.188;p=0.014). TGF-beta and IL-10 were negatively correlated with anti-SARS-CoV-2 specific protein antibody titer. For IL-10 (r=-0.065;p=0.39), for TGF-beta (r=-0.246;p=0.002). Further IFN-gamma was negatively correlated with TGF-beta (r=-0.268;p<0.001). Conclusion(s): Higher pro-inflammatory cytokines (IL-6, IFN-gamma) levels were associated with anti-SARS-CoV-2 spike protein-specific seroconversion, whereas higher anti-inflammatory cytokines IL-10 and TGF-beta were negatively associated with seroconversion after vaccination in renal transplant recipients. No conflict of interestCopyright © 2023

Anti-SARS-CoV-2 antibody responses in convalescent plasma donors with varying clinical manifestation severity of COVID-19

Background/Aim. Plasma containing a high titer of anti-SARS-CoV-2 antibodies, donated from individuals who re-covered from COVID-19, has the potential to be used as initial therapy for patients who have been infected (passive immunization). It is a challenge to find suitable donors. The aim of the study was to successively monitor antibody titer in donations and to investigate the correlation between an-tibody titer and the severity of the clinical manifestations. Methods. The retrospective study was conducted from May 1 to October 31, 2020, at the Blood Transfusion Insti-tute of Vojvodina. Donors had to meet certain criteria for inclusion in the study: proven SARS-CoV-2 infection, de-tected SARS-CoV-2 antibodies in the serum/plasma, ful-fillment of general criteria for performing plasmapheresis, and adequate laboratory findings. Results. During the study, 651 apheresis plasma units were collected and divided into two equal doses. Plasma was donated by 311 COVID-19 convalescents, including 208 (66.9%) men and 103 (33.1%) women. There were 15 (4.8%) plasma donors with asymptomatic infection, 235 (75. 6%) with a mild form of illness, 45 (14.5%) with a moderate form of illness, 16 (5.1%) with a severe form of illness, and none with a critical form of illness. Anti-SARS-CoV-2 IgG antibodies were pre-sent in the plasma of donors for more than 6 months after the disease. Plasma donors with a more severe clinical mani-festation of COVID-19 had stable antibody levels for a longer period. However, the Pearson correlation of clinical severity and antibody titer did not confirm a statistically sig-nificant correlation between the variables. Conclusion. An-ti-SARS-CoV-2 antibodies were present in the sample of re-covered patients, plasma donors, for more than 6 months after the disease. Even though no statistically significant correlation was found between the anti-SARS-CoV-2 anti-body titer and the clinical severity of COVID-19, in patients with a more severe clinical manifestations of the disease, stable antibody levels were maintained for a longer period.Copyright © 2022 Inst. Sci. inf., Univ. Defence in Belgrade. All rights reserved.

Safety of and antibody response to the BNT162b2 COVID-19 vaccine in adolescents and young adults with underlying disease

Background: Data are limited regarding the safety of and antibody response to the BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger ribonucleic acid vaccine in adolescents and young adults with underlying disease. Methods: This prospective observational study enrolled patients age 12–25 years with chronic underlying disease who received 2 doses of BNT162b2. A 18-item questionnaire was used to assess adverse events within 7 days post-vaccination, and data regarding severe adverse events were collected from electronic medical records. An antibody titer for the receptor-binding domain of the spike protein in SARS-CoV-2 was used to assess antibody response after the second vaccine dose. Results: Study participants were 429 patients (241 [56.2%] age 12–15 years;188 [43.8%] age 16–25 years). The most common underlying diseases were genetic or chromosomal abnormalities and/or congenital anomalies, followed by endocrine or metabolic diseases;32% of participants were immunocompromised. Severe adverse events were observed after the second dose in 1 (0.4%) patient age 12–15 years and in 2 (1.1%) patients age 16–25 years;all patients recovered. Seropositivity after the second vaccine dose was 99.0%. The geometric mean antibody titer was higher in patients age 12–15 years versus 16–25 years (1603.3 [1321.8–1944.7] U/mL vs. 949.4 [744.2–1211.0] U/mL). Compared with immunocompetent patients, immunocompromised patients had a lower antibody titer (2106.8 [1917.5–2314.7] U/mL vs. 467.9 [324.4–674.8] U/mL). Conclusions: Vaccination with BNT162b2 was acceptably safe and immunogenic for adolescents and young adults with underlying disease. © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases

Patients with B-cell malignancies experience reduced antibody responses with class switching defect following BNT162b2 SARS-CoV-2 vaccination

Vaccines having aided in escaping the majority of the population from immunological naïvety, our strategies are now shifting towards an increased focus on identifying and protecting the extremely vulnerable. We here describe the results of testing 12 patients, those with lymphoid malignancies having been targeted their B-cells for therapy with rituximab-containing regimens or a Bruton tyrosine kinase inhibitor, for anti-SARS-CoV-2 spike antibodies after receiving the BNT162b2 mRNA vaccine doses. The interval from last dosing of B-cell depletion therapy to SARS-CoV-2 vaccination was at median 5.3 (range 3.1–6.6) months. Using the ‘seroprotection' threshold of 775 [BAU/mL] for the anti-spike antibody titer, our finding points out the crucial unresponsiveness of the targeted population with 0/12 (0%) achieving ‘seroprotection'. Although IgG seroconversion was observed in 4/12 (33%), supporting the overall benefit of vaccination, the figures still point out a potential need for optimization of practice. IgA was further less responsive (unsuccessful ‘seroconversion' in 11/12 (92%)), implicating an underlying class switch defect. Those with depletion on B-cells are caught at a dilemma between, being too early and too late on receiving SARS-CoV-2 vaccines. They wish to get over their immunological naïvety at the earliest, while, in order to assure quality immune memory, are also required to hold the patience for their B-cells to repopulate. Although it remains an issue whether intensified vaccine schedules and/or regimens will lead to stronger immunogenicity or more effective boosters for non-responders, we shall take advantage of every increasing evidence in order to optimize current options. © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases

The peptide link between pathogens and human centromere proteins

This work tested the hypothesis that infection causes unexplained production of anti-centromere protein antibodies (ACA) via autoimmune cross-reactivity. To further examine the clinical origin of ACA, the overlapped peptides between human pathogens, including viruses, bacteria and fungi and centromere proteins (CENP-A, CENP-B and CENP-C) were assessed. We found a broad overlap of pathogenetic peptides with human centromere proteins. These data indicate potential immune cross-reactivity between pathogens and human centromere proteins. Additionally, the current findings corroborate a molecular and mechanistic framework for autoimmune disorders related to infection. Moreover, preliminary evidence for a potential role of infection in ACA-related autoimmune diseases was presented. © 2022 The Scandinavian Foundation for Immunology.

Preparation of the Monoclonal Antibody against the African Swine Fever Virus p54 Protein and Identification of the Antigenic Epitope.

The aim of this paper was to prepare specific monoclonal antibody (mAb) against African swine fever virus (ASFV) p54 protein. The p54 protein was expressed in Escherichia coli expression system and used as the antigen in mAb production. The spleen cells from the immunized BALB/c mice were fused with myeloma cells SP2/0. To screen the positive hybridoma cells, the purified p54 protein was used as envelope antigen for indirect ELISA. After four times' subcloning, the supernatant of hybridoma cells were used to identify mAb subtype, ascites were prepared via in vivo induction method in mice and then the mAb was purified. The titer of the mAb was detected by indirect ELISA, and the specificity of the mAb was identified by cross reactivity assay, IFA and Western blot. According to the predicted secondary structure of p54 protein, using the stepwise truncation method identified the epitope region of mAbs, and labeled the region in tertiary structure of p54 protein. Results were as follows: six hybridoma cells secreting p54 monoclonal antibody were successfully screened and named 28G12-1, 31G7-1, 31G7-2, 35F10-1, 35F10-2, 38D3-1, respectively. The heavy chains of 28G12-1, 31G7-1, and 31G7-2 were IgG2a type, the heavy chains of 35F10-1, 35F10-2, 38D3-1 were IgG1 type, light chains were all kappa chains. The lowest titer of mAb was 1:25 600, and having no cross reaction with PRRSV, PRV, PEDV, PPV, SADS-CoV, PCV2, the specificity was strong. All six monoclonal antibodies could recognize the 127-146 aa on carboxyl end. In this study, ASFV p54 protein and p54 monoclonal antibody were successfully obtained, and the epitopes of six mAbs were identified, these experimental data laid a foundation for the functional research of p54 protein and the study of ASFV epitope vaccine. Copyright © 2023 Editorial Board, Institute of Animal Science of the Chinese Academy of Agricultural Sciences. All rights reserved.

The long-term dynamics of serum antibodies against SARS-CoV-2.

Objective: To analyze the long-term dynamics of antibodies against SARS-CoV-2 and understand the impact of age, gender, and viral load on patients' immunological response. Methods: Serum samples were obtained from 231 COVID-19 positive patients from Macaé, in Rio de Janeiro state, in Brazil, from June 2020 until January 2021. The production of IgA, IgM, IgG, and IgE against S glycoprotein was analyzed using the S-UFRJ assay, taking into account the age, gender, and viral load. Results: Analysis of antibody production over 7 months revealed that IgA positivity gradually decreased after the first month. Additionally, the highest percentage of IgM positivity occurred in the first month (97% of patients), and declined after this period, while IgG positivity remained homogeneous for all 7 months. The same analysis for IgE revealed that almost all samples were negative. The comparison of antibody production between genders showed no significant difference. Regarding the age factor and antibody production, patients aged ≥60 years produced almost twice more IgA than younger ones (17-39 years old). Finally, a relationship between viral load and antibody production was observed only for older patients. Conclusions: Our work provides an overview of long-term production of antibodies against SARS-CoV-2, suggesting prolonged production of IgA and IgM antibodies for 3 months and continued IgG production for over 7 months. In addition, it identified a correlation between viral load and IgM titers in the older group and, finally, different IgA production between the age groups.

A systematic review of immunogenicity of Covid-19 vaccines in milk and serum of breastfeeding mothers based on existing evidence

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are administered worldwide. However, lactating women have been excluded from clinical trials, and limited information is available on the safety of vaccines against SARS-CoV-2 in lactating women. Therefore, comprehensive information is needed for mothers to make informed decisions about the need for vaccination to control the spread of the virus. This review study was conducted aimed to know the necessity of vaccination of breastfeeding mothers against the SARS-COV2 virus and to know the immune responses created in plasma and breast milk after the injection of COVID-19 vaccines. Method(s): In this systematic review study, Google Scholar, PubMed, and Science Direct information sources were used in the period of 2021 to 2022 to extract research articles containing information and the safety of milk and serum of lactating mothers vaccinated against SARS-COV-2. The articles which were not related to the purpose of the article were removed from the study process. Result(s): Out of 1770 articles related to the initial search, data from 30 papers met the inclusion criteria. Among the available vaccines, only the effects of AstraZeneca, Pfizer, and Moderna vaccines wereidentified on antibody secretion in breast milk and serum. The results of the presentresearch confirmed the presence of anti-SARS-CoV-2 antibodies in vaccinated serum and breast milk. So, IgG was the predominant antibody reported in many studies after vaccination.Thus, unlike post-viral immunity, the specific response of the vaccine is to dominate IgG and not IgA.The role of IgM was also less than that of other antibodies. Conclusion(s): Vaccination of lactating mothers enhances the protective effects of milk against COVID-19 infection. More efforts are needed to encourage breastfeeding mothers to be vaccinated and support breastfeeding during the outbreak. Copyright © 2022, Mashhad University of Medical Sciences. All rights reserved.