Antibody Avidity Research Articles

Новые подходы к ведению пациентов с нестойкой ремиссией круглогодичного аллергического ринита на фоне персистирующей хламидийной инфекции

Currently, allergic rhinitis is a global socioeconomic problem. According to current statistics, from 15 to 30% of the world’s population suffers from year-round or seasonal allergic rhinitis. Increasingly, the attention of Russian clinicians is attracted by the problem of year-round allergic rhinitis as there is an increase in the incidence in patients of the central zone of the Russian Federation with this form of rhinitis due to sensitization to house dust mite allergens, epidermal allergens of domestic animals, insect and mold allergens. Despite a timely diagnosis and received basic treatment, patients suffering from year-round allergic rhinitis often fail to achieve stable remission. Therefore, we can conclude that a more thorough diagnosis of the disease is needed, aimed at identifying other factors that affect the course of the disease. Objective. To develop a scheme for diagnosing a possible persistent respiratory chlamydial infection that affects the course of year-round allergic rhinitis in patients with a tendency to transient remissions. Materials and methods. Computed tomography of the paranasal sinuses, nasal swab for flora, PCR scraping of the nasal mucosa for the detection of Epstein–Barr virus (EBV) DNA, determination of viral DNA of cytomegalovirus infection (CMV) (PCR scraping of the nasal mucosa), determination of DNA in the scraping of epithelial cells of the nasal mucosa (PCR scraping) of human herpes virus type 6 (HHV-6 type). Patients who had pathological changes in computed tomography of the paranasal sinuses, deviations from the normal flora during bacteriological culture, and positive results in the PCR study of the above infections were excluded from the study. Then, PCR scraping of the nasopharyngeal mucosa for the detection of chlamydia pneumoniae, a survey of complaints (SNOT-22 questionnaire), data from an objective examination method (examination of ENT organs using video endoscopic technologies), an immunological examination of blood serum for IgG antibodies to chlamydial infection, further avidity of IgG antibodies to chlamydia pneumoniae and serum IL-6. Conclusion. The proposed diagnostic scheme will allow identifying a possible persistent respiratory chlamydial infection, which is the cause of transient remission of year-round allergic rhinitis, and developing a new integrated approach to the management of patients with year-round allergic rhinitis associated with this infection.

Elevated BMI reduces the humoral response to SARS-CoV-2 infection.

Class III obesity (body mass index [BMI] ≥ 40 kg m-2) significantly impairs the immune response to SARS-CoV-2 vaccination. However, the effect of an elevated BMI (≥ 25 kg m-2) on humoral immunity to SARS-CoV-2 infection and COVID-19 vaccination remains unclear. We collected blood samples from people who recovered from SARS-CoV-2 infection approximately 3 and 13 months of post-infection (noting that these individuals were not exposed to SARS-CoV-2 or vaccinated in the interim). We also collected blood samples from people approximately 5 months of post-second dose COVID-19 vaccination (the majority of whom did not have a prior SARS-CoV-2 infection). We measured their humoral responses to SARS-CoV-2, grouping individuals based on a BMI greater or less than 25 kg m-2. Here, we show that an increased BMI (≥ 25 kg m-2), when accounting for age and sex differences, is associated with reduced antibody responses after SARS-CoV-2 infection. At 3 months of post-infection, an elevated BMI was associated with reduced antibody titres. At 13 months of post-infection, an elevated BMI was associated with reduced antibody avidity and a reduced percentage of spike-positive B cells. In contrast, no significant association was noted between a BMI ≥ 25 kg m-2 and humoral immunity to SARS-CoV-2 at 5 months of post-secondary vaccination. Taken together, these data showed that elevated BMI is associated with an impaired humoral immune response to SARS-CoV-2 infection. The impairment of infection-induced immunity in individuals with a BMI ≥ 25 kg m-2 suggests an added impetus for vaccination rather than relying on infection-induced immunity.

A Bivalent MAPS Vaccine Induces Protective Antibody Responses against Salmonella Typhi and Paratyphi A.

Infections by Salmonella Typhi and Paratyphi A strain are still a major cause of morbidity and mortality in developing countries. Generation of antibodies against the Vi capsular polysaccharide of S. Typhi via either pure polysaccharide or protein-polysaccharide conjugate is a very effective way to protect against S. Typhi. To date, there is no commercially available vaccine against S. Paratyphi A. The O-specific polysaccharide (OSP) has been generally considered a good vaccine target for Paratyphi A. Here, a bivalent vaccine against Vi and OSP was generated using the Multiple Antigen Presenting System (MAPS). Three different protein constructs, including CRM197, rEPA of Pseudomonas, and a pneumococcal fusion protein SP1500-SP0785, were fused to Rhizavidin (Rhavi) and evaluated their impact on immunogenicity when incorporated as fusion proteins affinity-bound to the two polysaccharides. We compared the antibody responses, antibody avidity, and cidal activity of sera post-immunization with monovalent vs. combination vaccines. We also wished to evaluate the generation of Vi-specific memory B cells in mice. We found little interference when combination vaccine was compared to monovalent vaccines with respect to antibody concentration and cidal activity of sera. Significant affinity maturation was noted for both Vi and OSP antigens. Thus, our preclinical results with a combination Vi- and OSP-MAPS vaccine strongly support the feasibility of this approach and its application of this approach to other important salmonella and Shigella species.

Rubella virus IgM and IgG antibodies with avidity in pregnant women and outcomes at a tertiary facility in Ghana.

Congenital rubella syndrome (CRS) is a recognised cause of childhood deafness and blindness caused by the transplacental transmission of rubella virus during pregnancy. Women in the reproductive age group, and by extension their unborn babies may therefore be at increased risk. The prevalence of Rubella virus specific IgM and IgG antibodies, including IgG avidity, was determined in pregnant women attending the antenatal clinic at a Teaching Hospital in Ghana. One hundred and forty-five women in their second and third trimesters of pregnancy from the outpatient clinic were recruited over a period of 2 months after written informed consent was obtained. Study participants completed a questionnaire and venous blood drawn for IgM, IgG, and avidity testing using SERION ELISA (SERION® Immunologics, Würzburg, Germany). Babies of mothers with positive or indeterminate IgM and low avidity IgG antibodies were offered specialist cardiological, ophthalmological or hearing assessment during follow up. One hundred and twenty-eight (88.3%) had only IgG antibodies, 5 (3.4%) had IgM and IgG antibodies, while 12 (8.3%) had no antibodies. No patient had IgM antibodies alone. Ten women (6.9%) had indeterminate levels of IgM antibodies. Majority of the women had high avidity IgG antibodies, while 5 (3.4%) had low avidity antibodies. No patient had IgM with low avidity antibodies. There was no statistical association between socio-demographic factors and the presence of IgM, IgG (low or high avidity) antibodies. Of all the children followed, none had the clinical definition of CRS. Consistent with the World Health Organization elimination strategy for measles and rubella viruses, non-immune women in the reproductive age group should be vaccinated. The immunization programme should be expanded to include teenagers and adults. Though Congenital Rubella Syndrome was not detected, the risk still remains.

Conformation specific antagonistic high affinity antibodies to the RON receptor kinase for imaging and therapy

The RON receptor tyrosine kinase is an exceptionally interesting target in oncology and immunology. It is not only overexpressed in a wide variety of tumors but also has been shown to be expressed on myeloid cells associated with tumor infiltration, where it serves to dampen tumour immune responses and reduce the efficacy of anti-CTLA4 therapy. Potent and selective inhibitory antibodies to RON might therefore both inhibit tumor cell growth and stimulate immune rejection of tumors. We derived cloned and sequenced a new panel of exceptionally avid anti-RON antibodies with picomolar binding affinities that inhibit MSP-induced RON signaling and show remarkable potency in antibody dependent cellular cytotoxicity. Antibody specificity was validated by cloning the antibody genes and creating recombinant antibodies and by the use of RON knock out cell lines. When radiolabeled with 89-Zirconium, the new antibodies 3F8 and 10G1 allow effective immuno-positron emission tomography (immunoPET) imaging of RON-expressing tumors and recognize universally exposed RON epitopes at the cell surface. The 10G1 was further developed into a novel bispecific T cell engager with a 15 pM EC50 in cytotoxic T cell killing assays.

Antibody Avidity Maturation Following Recovery From Infection or the Booster Vaccination Grants Breadth of SARS-CoV-2 Neutralizing Capacity.

Cross-neutralizing capacity of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is important in mitigating (re-)exposures. Role of antibody maturation, the process whereby selection of higher affinity antibodies augments host immunity, to determine SARS-CoV-2 neutralizing capacity was investigated. Sera from SARS-CoV-2 convalescents at 2, 6, or 10 months postrecovery, and BNT162b2 vaccine recipients at 3 or 25 weeks postvaccination, were analyzed. Anti-spike IgG avidity was measured in urea-treated ELISAs. Neutralizing capacity was assessed by surrogate neutralization assays. Fold change between variant and wild-type neutralization inferred the breadth of neutralizing capacity. Compared with early-convalescent, avidity indices of late-convalescent sera were significantly higher (median, 37.7 [interquartile range 28.4-45.1] vs 64.9 [57.5-71.5], P < .0001). Urea-resistant, high-avidity IgG best predicted neutralizing capacity (Spearman r = 0.49 vs 0.67 [wild-type]; 0.18-0.52 vs 0.48-0.83 [variants]). Higher-avidity convalescent sera better cross-neutralized SARS-CoV-2 variants (P < .001 [Alpha]; P < .01 [Delta and Omicron]). Vaccinees only experienced meaningful avidity maturation following the booster dose, exhibiting rather limited cross-neutralizing capacity at week 25. Avidity maturation was progressive beyond acute recovery from infection, or became apparent after the booster vaccine dose, granting broader anti-SARS-CoV-2 neutralizing capacity. Understanding the maturation kinetics of the 2 building blocks of anti-SARS-CoV-2 humoral immunity is crucial.

Potent high-avidity neutralizing antibodies and T cell responses after COVID-19 vaccination in individuals with B cell lymphoma and multiple myeloma

Individuals with hematologic malignancies are at increased risk for severe coronavirus disease 2019 (COVID-19), yet profound analyses of COVID-19 vaccine-induced immunity are scarce. Here we present an observational study with expanded methodological analysis of a longitudinal, primarily BNT162b2 mRNA-vaccinated cohort of 60 infection-naive individuals with B cell lymphomas and multiple myeloma. We show that many of these individuals, despite markedly lower anti-spike IgG titers, rapidly develop potent infection neutralization capacities against several severe acute respiratory syndrome coronavirus 2 variants of concern (VoCs). The observed increased neutralization capacity per anti-spike antibody unit was paralleled by an early step increase in antibody avidity between the second and third vaccination. All individuals with hematologic malignancies, including those depleted of B cells and individuals with multiple myeloma, exhibited a robust T cell response to peptides derived from the spike protein of VoCs Delta and Omicron (BA.1). Consistently, breakthrough infections were mainly of mild to moderate severity. We conclude that COVID-19 vaccination can induce broad antiviral immunity including ultrapotent neutralizing antibodies with high avidity in different hematologic malignancies.

Analysis of a German blood donor cohort reveals a high number of undetected SARS-CoV-2 infections and sex-specific differences in humoral immune response.

Seroprevalence studies can contribute to a better assessment of the actual incidence of infection. Since long-term data for Germany are lacking, we determined the seroprevalence of immunoglobulin G (IgG) antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in residual plasma samples of 3,759 German regular blood donors between July 2020 and June 2021. Over almost the entire study period, the incidences determined based on our data were higher than those officially reported by the Robert Koch Institute, the public health institute in Germany. Using our serological testing strategy, we retrospectively detected natural infection in 206/3,759 (5.48%; 95% confidence interval (CI): 4.77-6.25) individuals. The IgG seroprevalence ranked from 5.15% (95% CI: 3.73-6.89) in Lower Saxony to 5.62% (95% CI: 4.57-6.84) in North Rhine Westphalia. The analyses of follow-up samples of 88 seropositive blood donors revealed a comparable fast decay of binding and neutralizing anti-SARS-CoV-2 IgG antibodies. The antibody avidity remained at a low level throughout the whole follow-up period of up to 181 days. Interestingly, female donors seem to express a stronger and longer lasting humoral immunity against the new coronavirus when compared to males. Conclusion: Overall, our data emphasizes that seroprevalence measurements can and should be used to understand the true incidence of infection better. Further characterization of follow-up samples from seropositive donors indicated rapid antibody waning with sex-specific differences concerning the strength and persistence of humoral immune response.

Verification of a case of mixed infection with Lyme disease, tick-borne encephalitis and COVID-19

Background. The relationship between pathogens of new diseases and tick-borne infections is an underinvestigated direction in the problem of infectious diseases.The aim. To show the features of identifying the markers of Borrelia burgdorferi, tickborne encephalitis and SARS-CoV-2 pathogens on the example of a case of a triple mixed infection (Lyme disease, tick-borne encephalitis and COVID-19) and using comprehensive studies.Methods. In 2019–2021, a comprehensive study of 7 blood samples from a patient with mixed infection was carried out. We used real-time polymerase chain reaction (PCR), enzyme immunoassay (ELISA) and determined antigen, IgM, IgG antibodies, and avidity index (AI) of IgG antibodies.Results. Ixodid tick-borne borreliosis was diagnosed in a patient 5 months after contagion. Only high-avid Lyme-IgG antibodies were detected. Low-avid Lyme- IgG antibodies appeared against the background of a reduced general condition. At the same time, high-avid IgG (cut-off index (COI) – 7.8) and IgM (COI = 1.2) antibodies to the TBE virus were detected. In July 2020, the patient was infected with SARSCoV-2. TBE virus which passed into the body simultaneously with Borrelia in the fall of 2019 was activated. Although the patient did not have specific symptoms of TBE, in subsequent blood samples (No. 4, 5, 6) we found TBEV antigen (optical density (OD) – 4.3; 1.9 and 2.0 respectively) and IgM (COI = 1.3; 0,9 and 0 respectively). These results were recognized as TBEV activation, which contributed to an increase in the avidity of IgG antibodies (AI = 65 %; 100 % and 63 % respectively). IgM antibodies to SARSCoV-2 virus were not detected, as opposed to the high levels of IgG (COI = 8.2; 8.1; 8.4 and 14.7 respectively).Conclusions. Therefore, using not only the common methods of diagnosing (PCR and ELISA), but also the determination of the antibody avidity degree, we have shown that when analyzing a case of a triple mixed infection, B. burgdorferi dominates in the human body and causes a long-term chronic course of the disease.

Maturation of SARS-CoV-2 Spike-specific memory B cells drives resilience to viral escape

Memory B cells (MBCs) generate rapid antibody responses upon secondary encounter with a pathogen. Here, we investigated the kinetics, avidity, and cross-reactivity of serum antibodies and MBCs in 155 SARS-CoV-2 infected and vaccinated individuals over a 16-month time frame. SARS-CoV-2-specific MBCs and serum antibodies reached steady-state titers with comparable kinetics in infectedand vaccinated individuals. Whereas MBCs of infected individuals targeted both prefusion and postfusion Spike (S), most vaccine-elicited MBCs were specific for prefusion S, consistent with the use of prefusion-stabilized S in mRNA vaccines. Furthermore, a large fraction of MBCs recognizing postfusion S cross-reacted with human betacoronaviruses. The avidity of MBC-derived and serum antibodies increased over time resulting in enhanced resilience to viral escape by SARS-CoV-2 variants, including Omicron BA.1 and BA.2 sublineages, albeit only partially for BA.4 and BA.5 sublineages. Overall, the maturation of high-affinityand broadly reactive MBCs provides the basis for effective recall responses to future SARS-CoV-2 variants.

Study of avidity-ELISA: Comparison of chaotropic agents, incubation temperature and affinity maturation after meningococcal immunization

The avidity index (AI) measures the binding strength between the antibody and the antigen, reflecting the affinity maturation. It can be measured by a modified ELISA, adding a chaotropic agent to disrupt the antigen x antibody interaction. However, details of the protocols used affect the final results. We compared the AI of mice sera after a three-dose immunization with meningococcal antigens using different adjuvants. The AI was assessed using potassium thiocyanate (KSCN) and urea as chaotropic agents, incubated at 4 °C, room temperature (RT) and 37 °C. KSCN presented statistically different results when the incubation was set at 4 °C vs RT and 4 °C vs 37 °C, thus, the mean AI obtained were lower. For Urea, 4 °C vs 37 °C presented relevant differences. Using whole-cells suspensions or OMVs as coating antigen provided similar results in some protocols. Thus, the affinity maturation was assessed after each immunization dose and adjuvant use (aluminium hydroxide and dimethyldioctadecylammonium bromide) supported affinity maturation. It is important to study the AI as a functional parameter of humoral response, and both KSCN and Urea are suitable chaotropic agents, however, the protocols should be standardized considering the nature of the antigen, the chaotropic activity and overall laboratory conditions. Adjuvants are important tools to improve antibody avidity following immunization.

Congenital Cytomegalovirus Infection and Maternal Primary Cytomegalovirus Infection in Universal Newborn Hearing Screening Referral Patients: A Prospective Cohort Study

Background: There are no detailed reports in the literature on maternal cytomegalovirus antibody screening for universal newborn hearing screening (UNHS) referral patients. We examined maternal cytomegalovirus antibody screening results and estimated the incidence of maternal primary cytomegalovirus infection among UNHS referral patients. Methods: During September 2013–March 2021, fresh urine samples were collected in the first week after birth from 98 neonates with UNHS referral results at 15 obstetrical institutions in Mie, Japan (the first hearing screening). We performed a real-time polymerase chain reaction analysis to detect cytomegalovirus DNA in the samples. Infants with ≥200 copies/mL of cytomegalovirus DNA were diagnosed with congenital cytomegalovirus (cCMV) infection. A second hearing screening was performed, and patients with positive results were sent to the otorhinolaryngologists for further examinations of congenital hearing loss. We calculated incidence rates (%) with 95% confidence intervals (CIs) for cCMV infection among patients with UNHS referral results and maternal primary cytomegalovirus infection among patients who underwent maternal cytomegalovirus antibody screening. Results: Among the 98 neonates with UNHS referral results (the first hearing screening), 5 were diagnosed with cCMV infection (incidence rate: 5.1%; 95% CI: 0.8–9.5). All five patients with cCMV had positive second hearing screening results and were sent to their otorhinolaryngologists. All five were diagnosed with congenital hearing loss, and four were diagnosed with congenital hearing loss secondary to cCMV infection. The remaining patient with cCMV infection was diagnosed with congenital hearing loss unrelated to cCMV infection. Of the 98 patients, 60 underwent maternal cytomegalovirus antibody screening. Among the 60 patients, six had maternal primary cytomegalovirus infection during pregnancy (incidence rate: 10.0%; 95% CI: 2.4–17.6). Of the six patients, four were positive for cytomegalovirus immunoglobulin (CMV Ig) G and IgM antibodies in maternal blood with low CMV IgG antibody avidity results during early pregnancy, while the remaining two had maternal CMV IgG antibody seroconversion during pregnancy. Conclusions: This is the first study to examine the maternal primary cytomegalovirus infection incidence rate in patients with UNHS referral results (the first hearing screening). We identified a 10-fold higher risk in this population (10.0%) than in the general population (0.98%).

Cross neutralization of SARS-CoV-2 omicron subvariants after repeated doses of COVID-19 mRNA vaccines.

We have measured the humoral response to messenger RNA (mRNA) vaccines in COVID-19 naïve and convalescent individuals. Third doses of mRNA COVID-19 vaccines induced a significant increase in potency and breadth of neutralization against SARS-CoV-2 variants of concern (VoC) including Omicron subvariants BA.1, BA.2, and BA.2.12.1, that were cross-neutralized at comparable levels and less for BA.4/5. This booster effect was especially important in naïve individuals that only after the third dose achieved a level that was comparable with that of vaccinated COVID-19 convalescents except for BA.4/5. Avidity of RBD-binding antibodies was also significantly increased in naïve individuals after the third dose, indicating an association between affinity maturation and cross neutralization of VoC. These results suggest that at least three antigenic stimuli by infection or vaccination with ancestral SARS-CoV-2 sequences are required to induce high avidity cross-neutralizing antibodies. Nevertheless, the circulation of new subvariants such as BA.4/5 with partial resistance to neutralization will have to be closely monitored and eventually consider for future vaccine developments.

Longitudinal antibody titer, avidity, and neutralizing responses after SARS-CoV-2 infection

While waning immunity and SARS-CoV-2 variant immune escape continue to result in high infection rates worldwide, associations between longitudinal quantitative, qualitative, and functional humoral immune responses after SARS-CoV-2 infection remain unclear. In this study, we found significant waning of antibody against Spike S1 (R = −0.32, p = 0.035) and N protein (R = −0.39, p = 0.008), while RBD antibody moderately decreased (R = −0.19, p = 0.203). Likewise, neutralizing antibody titer (ND50) waned over time (R = −0.46, p = 0.001). In contrast, antibody avidity increased significantly over time for Spike S1 (R = 0.62, p = 6.0e−06), RBD (R = 0.54, p = 2.0e−04), and N (R = 0.33, p = 0.025) antibodies. Across all humoral responses, ND50 strongly associated with Spike S1 (R = 0.85, p = 2.7e−13) and RBD (R = 0.78, p = 2.9e−10) antibodies. Our findings provide longitudinal insight into humoral immune responses after infection and imply the potential of Spike S1/RBD antibody titer as surrogate correlates of protection.

16 SARS-COV-2 INFECTION AND VACCINATION PATTERNS DETERMINE LONG-TERM ANTIBODY RESPONSES IN NURSING HOME RESIDENTS: DATA FROM NH-COVAIR

Abstract Background Older Nursing Home Residents (NHRs) are at greatest risk of morbidity and mortality from SARS-CoV-2, particularly in the context of both waning vaccine efficacy and the emergence of Variants-of-Concern (VOCs). However, the determinants of long-term vaccine-induced protective antibody responses are yet to be determined in this group. Methods NH-COVAIR recruited older NHRs for comprehensive clinical and frailty (NH-FRAIL) assessment. Blood samples were obtained pre-vaccination, at 6-weeks and 6-months following primary vaccination and 6-months following booster vaccination. Antibody titres were measured using both an electrochemiluminescence assay and a custom bead-based array (Luminex™) to measure antibody titre and avidity for Wuhan strain/major VOC antigens. Stepwise adjusted linear regression (log-transformed) assessed longitudinal determinants of vaccine-induced antibody responses. Results Of 86 participants (81.1 ± 10.8 years; 65% female), just under half (45.4%) had evidence of previous SARS-CoV-2 infection. All NHRs mounted a significant antibody-response to vaccination at 5 weeks followed by a significant decrease in antibody titre by 6 months. Previous SARS-CoV-2 infection was the strongest predictor of antibody waning at all timepoints (β: 3.59; 2.89, 4.28; P &amp;lt; 0.001 for 6-months). Independent of infection history, both age (β: –0.05; –0.08, –0.02; p&amp;lt;0.001) and frailty (β: –0.22; –0.33, –0.11; p&amp;lt;0.001) were associated with faster antibody waning at 6-months. Cross-reactivity and avidity were significantly lower for Beta (B.1.351) and Gamma (P.1) VOC strains (all p&amp;lt;0.001). Additionally, there was faster antibody waning and significantly reduced antibody avidity to Beta and Gamma VOCs in SARS-CoV-2 naïve NHRs. Conclusion Older NHRs are capable of mounting protective antibody responses to SARS-CoV-2 vaccination. Responses were more durable, with a greater cross-reactivity to and avidity for VOCs in those with previous SARS-CoV-2 infection. Increasing age and greater frailty in NHRs was associated with faster antibody waning. Our findings support ongoing serological surveillance and use of additional vaccine doses in older NHRs, particularly in those without previous SARS-CoV-2 exposure.

Development of antibody-dependent cellular cytotoxicity in response to recombinant and live-attenuated herpes zoster vaccines

Zoster vaccines generate antibody responses against varicella-zoster virus (VZV). We compared antibody-dependent cell cytotoxicity (ADCC) elicited by zoster vaccine live (ZVL) and recombinant zoster vaccine (RZV). ADCC mediated by antibodies against VZV lysate (VZV-ADCC) and recombinant glycoprotein E (gE-ADCC) was measured using plasma from 20 RZV- and 20 ZVL-recipients, including half 50–60-years-old and half ≥70-years-old. Solid phase-bound anti-VZV antibodies stimulated TNFα in NK cells as measured by flow cytometry or ELISA. VZV-ADCC pre- and post-immunization was higher in younger vaccinees. ZVL did not appreciably increase VZV-ADCC, whereas RZV increased VZV-ADCC in older vaccinees. ELISA-measured gE-ADCC was similar across groups pre-immunization; significantly increased after ZVL; and RZV and was higher in younger RZV than ZVL recipients. IgG3 antibodies increased after RZV and ZVL, with greater anti-gE than anti-VZV responses. Moreover, gE-ADCC strongly correlated with anti-gE antibody avidity, but there were no appreciable correlations between VZV-ADCC and avidity. NK cells stimulated by anti-gE antibodies showed increased IFNγ and CD107a expression, which was not observed with anti-VZV antibodies. In conclusion, anti-gE antibodies generated more robust ADCC than anti-VZV antibodies. RZV induced higher ADCC antibodies than ZVL depending on the antigen and age of vaccinees. Older adults had lower ADCC antibodies before and after vaccination than younger adults.

Immunogenicity of COVID-19 mRNA vaccines in patients with acute myeloid leukemia and myelodysplastic syndrome

Immunocompromised patients are susceptible to complications from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The mRNA vaccines BNT162b2 and mRNA-1273 are effective in immunocompetent adults, but have diminished activity in immunocompromised patients. We measured anti-spike SARS-CoV-2 antibody (anti-S) response, avidity, and surrogate neutralizing antibody activity in COVID-19 vaccinated patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Anti-S was induced in 89% of AML and 88% of MDS patients, but median levels were significantly lower than in healthy controls. SARS-CoV-2 antibody avidity and neutralizing activity from AML patients were significantly lower than controls. Antibody avidity was significantly greater in patients after mRNA-1273 versus BNT162b2; there were trends toward higher anti-S levels and greater neutralizing antibody activity after mRNA-1273 vaccination. Patients with AML and MDS are likely to respond to COVID-19 mRNA vaccination, but differences in anti-S levels, avidity, and neutralizing antibody activity may affect clinical outcomes and require further study.

Structural, functional, and physiological properties of anti-(4-hydroxy-3-nitrophenyl)acetyl antibodies during the course of affinity maturation.

Structural and functional analyses of antibodies in the affinity maturation pathway can help us understand the molecular mechanisms of protein recognition. Using one of the haptens, (4-hydroxy-3-nitrophenyl)acetyl (NP), various monoclonal antibodies have been obtained, either at the early or late stage of immunization. The variable regions of monoclonal antibodies and their site-directed mutants can also be obtained as single-chain Fv (scFv) antibodies. The change in antigen-binding affinity and avidity of matured-type antibodies from germline-type antibodies could be evaluated based on binding kinetics and thermodynamics, proposing the antigen recognition mode. Crystal structures of a germline-type antibody, N1G9, and a matured-type antibody, C6, in complex with NP were determined, revealing different antigen-binding mode at atomic resolution. Notably, the Tyr to Gly mutation at the 95th residue of the heavy chain is critical for changing the configuration of complementarity determining region 3, which is involved in antigen binding. Furthermore, thermal stability analyses of scFv antibodies have revealed trade-off between antigen-binding affinity and thermal stability in the antigen-unbound state. To increase affinity, the stability of the variable region may be decreased, possibly due to protein architecture. The high stability of germline-type antibodies and the low stability of matured-type antibodies, which increase upon antigen binding, can be explained by the stability of antibodies required at the respective stages of immunization.

Laboratory assessment of state of post-vaccination humoral immunity to infections with aerosol transmission mechanism

The review considers questions about the place of laboratory diagnostics in preventive medicine, in particular, about the possibilities of using laboratory methods in controlling the vaccination of infections with an aerosol transmission mechanism (measles, rubella, mumps, chickenpox, influenza, pneumococcal infection, pertussis, diphtheria, COVID-19). The article highlights the main laboratory methods of seromonitoring (enzyme immunoassay, radial hemolysis reaction in gel, dot-immunoassay, antibody avidity determination, hemagglutination inhibition reaction, microneutralization reaction, FAMA, plaque suppression reaction), their advantages and disadvantages. Also presented a block of data on alternative biomarkers (enzymes, lipids, trace elements, hormones, etc.). which serve as potential predictors of vaccination efficacy. The search for new biomarkers of the effectiveness of the formation of post-vaccination immunity opens up new possibilities for predicting the effectiveness of vaccination, which makes their study a promising direction in the field of vaccinology and laboratory immunology.

Dynamics of humoral and cellular immune responses after homologous and heterologous SARS-CoV-2 vaccination with ChAdOx1 nCoV-19 and BNT162b2.

BackgroundVaccines are an important means to overcome the SARS-CoV-2 pandemic. They induce specific antibody and T-cell responses but it remains open how well vaccine-induced immunity is preserved over time following homologous and heterologous immunization regimens. Here, we compared the dynamics of humoral and cellular immune responses up to 180 days after homologous or heterologous vaccination with either ChAdOx1-nCoV-19 (ChAd) or BNT162b2 (BNT) or both.MethodsVarious tests were used to determine the humoral and cellular immune response. To quantify the antibody levels, we used the surrogate neutralization (sVNT) assay from YHLO, which we augmented with pseudo- and real virus neutralization tests (pVNT and rVNT). Antibody avidity was measured by a modified ELISA. To determine cellular reactivity, we used an IFN-γ Elispot, IFN-γ/IL Flurospot, and intracellular cytokine staining.FindingsAntibody responses significantly waned after vaccination, irrespective of the regimen. The capacity to neutralize SARS-CoV-2 – including variants of concern such as Delta or Omicron – was superior after heterologous compared to homologous BNT vaccination, both of which resulted in longer-lasting humoral immunity than homologous ChAd immunization. All vaccination regimens induced stable, polyfunctional T-cell responses.InterpretationThese findings demonstrate that heterologous vaccination with ChAd and BNT is a potent alternative to induce humoral and cellular immune protection in comparison to the homologous vaccination regimens.FundingThe study was funded by the German Centre for Infection Research (DZIF), the European Union's “Horizon 2020 Research and Innovation Programme" under grant agreement No. 101037867 (VACCELERATE), the “Bayerisches Staatsministerium für Wissenschaft und Kunst” for the CoVaKo-2021 and the For-COVID projects and the Helmholtz Association via the collaborative research program “CoViPa”. Further support was obtained from the Federal Ministry of Education and Science (BMBF) through the “Netzwerk Universitätsmedizin”, project “B-Fast” and “Cov-Immune”. KS is supported by the German Federal Ministry of Education and Research (BMBF, 01KI2013) and the Else Kröner-Stiftung (2020_EKEA.127).