Humoral Antibody Research Articles

Pal Affects the Proliferation in Macrophages and Virulence of Brucella, and as Mucosal Adjuvants, Provides an Effective Protection to Mice Against Salmonella Enteritidis.

The purpose of this study was to elucidate the roles of peptidoglycan-associated lipoprotein (Pal protein) in the proliferation of Brucella in macrophage and bacterial virulence, and to evaluate the immune effect of Pal protein to Salmonella enteritidis. Murine macrophage-like cell line Raw264.7 was stimulated by recombinant Pal protein, and the expression of TNF-α and IFN-γ were up-regulated, but not it of IL-1β and IL-6. The macrophages infection and in vitro simulated stress assays showed that deletion of pal gene reduced the proliferation of Brucella in macrophages, the survival in acidic, oxidative and polymyxin B-contained environment. The mice infection assay showed that mice challenged with the pal mutant strain were found to have more severe splenomegaly, but less bacterial load. After oral immunization of mice, Pal protein induced a higher titer of mucosal and humoral antibody (IgA and IgG) against heat-killed Salmonella enteritidis, and a stronger Th1 cellular immune response. The challengte experiments showed Pal protein elevated the survival rate and reduced the bacterial load of spleens in immunized mice. In conclusion, our results revealed the important roles of pal gene in Brucella virulence, and Pal protein was a potentially valuable adjuvant against mucosal pathogens, such as Salmonella enteritidis.

Fourth dose of the SARS-CoV-2 vaccine in kidney transplant recipients with previously impaired humoral antibody response

Fourth dose of the SARS-CoV-2 vaccine in kidney transplant recipients with previously impaired humoral antibody response

Responses of Humoral and Cellular Immune Mediators in BALB/c Mice to LipX (PE11) as Seed Tuberculosis Vaccine Candidates.

A member of the pe/ppe gene family, lipX (pe11), is capable of directing persistent Mycobacterium tuberculosis and avoiding host immune responses. Some studies have indicated that LipX (PE11) can detect humoral antibodies in tuberculosis patients. Hence, information on immune mediators' responses to this protein is essential to understand its protective efficacy against M. tuberculosis infections. This study aimed to examine the response of immune mediators to pCDNA3.1-lipX expression in vivo. In the experiment, pCDNA3.1-lipX was injected into BALB/c strain male mice aged between 6 and 8 weeks, and they were compared to groups injected with pCDNA3.1 and without injection. The injection was carried out three times intramuscularly every two weeks. Blood was taken retro-orbitally and used for humoral response analysis by Western blotting against LipX-His protein. Simultaneously, the splenocytes were cultured and induced with LipX-His protein for cellular immunity analyses. Our study showed that the recombinant DNA of pCDNA3.1-lipX induced a humoral and cellular immune response, especially in IL-4, IL-12, and IFN-γ, which are the primary cellular responses to M. tuberculosis infections. However, additional studies, such as a challenge study, are needed to strengthen the argument that this plasmid construction is feasible as a tuberculosis seed vaccine candidate.

Immunosuppressive Effect of Methanol Extract and Ethyl Acetate Fraction of Breadfruit [Artocarpus altilis (Park.) Fosberg] Leaves

Background: Artocarpus sp. contained a variety of flavonoids, some of which have been shown to reduce inflammation. In vitro anti-inflammatory activity of breadfruit (Artocarpus altilis (Park.) Fosberg) has been demonstrated. Chronic inflammation can occur when immune defence mechanisms are activated by inflammatory conditions. Objectives: This study examined breadfruit leaf methanol extract and ethyl acetate fraction immunosuppressive effects. Material and Methods: The bioactive compounds in breadfruit leaves were extracted in methanol via maceration and fractionation in ethyl acetate via liquid-liquid extraction. The in vivo immunosuppressive effect was evaluated in male Swiss albino mice by humoral antibody titer, delayed-type hypersensitivity, and phagocytic index assays. Results: According to phytochemical screening, flavonoids and steroids were found in the extract and its ethyl acetate fraction. The breadfruit leaf extract and fraction showed an immunosuppressive effect through phagocytic index<1, and the thymus gland index was significantly decreased (p<0.05) compared to control. The breadfruit leaf extract and the ethyl acetate fraction were able to inhibit the production of antibodies and DTH reactions, two types of immune responses. Conclusions: The extract of breadfruit leaves and the ethyl acetate fraction showed immunosuppressive properties.

A Walk through Gumboro Disease

Infectious bursal disease (IBD), caused by an Avibirnavirus, belonging to the family Birnaviridae, is an immunosuppressive disease that affects 3–6-week-old chickens, resulting in clinical or subclinical infection. Although clinical disease occurs in chickens, turkeys, ducks, guinea fowl, and ostriches can be also infected. IBD virus (IBDV) causes lymphoid depletion of the bursa, which is responsible for the severe depression of the humoral antibody response, primarily if this occurs within the first 2 weeks of life. IBD remains an issue in chicken meat production due to economic losses caused by the spread of variants or subtypes, resistant to the most common vaccines, responsible for a subclinical disease characterized by reduced growth performance and increased susceptibility to secondary infections. Very virulent strains of classical serotype 1 are also common in several countries and can cause severe disease with up to 90% mortality. This review mainly focuses on the immunosuppressive effect of the IBDV and potential vaccination strategies, capable of overcoming challenges associated with the optimal time for vaccination of offspring, which is dependent on maternal immunity and IBDV variant occurrence.

The Molecular Epidemiology of Prevalent Klebsiella pneumoniae Strains and Humoral Antibody Responses against Carbapenem-Resistant K. pneumoniae Infections among Pediatric Patients in Shanghai.

ABSTRACTCarbapenem-resistant Klebsiella pneumoniae (CRKP) has caused wide dissemination among pediatric patients globally and thus has aroused public concern. Here, we investigated the clinical epidemiological characteristics of 140 nonreplicate clinical K. pneumoniae strains isolated from pediatric patients between January and December 2021. Of all isolates, 16.43% (23 of 140) were CRKP strains, which predominantly contained KPC carbapenemase. wzi sequencing demonstrated that KL47 (65.22%, 15 of 23) was the most frequent capsular type, followed by KL64 (17.39%, 4 of 23). A total of 23 CRKP strains were classified into three different O-genotypes, including OL101 (65.22%, 15 of 23), O1 (26.09%, 6 of 23), and O3 (8.7%, 2 of 23). Interestingly, KL47 strains were strongly associated with OL101, while KL64 strains were all linked with O1. Some capsule-deficient strains were identified by serological typing, phage-typing, depolymerase-typing, and uronic acid assay. In this study, compared with healthy children, higher titers of anti-capsular polysaccharides (CPS) IgG were first detected in the sera of K47 and K64 K. pneumoniae-infected children, which had the effective bactericidal activity against corresponding serotype K. pneumoniae strains. These findings will facilitate the development of novel therapeutic and vaccine strategies against K. pneumoniae infection in children.IMPORTANCE The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains resistant to numerous antibiotics and the limited therapeutic options available have become an urgent health threat to the immunocompromised pediatric population. Vaccines and antibodies, especially those targeting capsular polysaccharides, may be novel and effective prevention and treatment options. Thus, it is important to understand the spread of CRKP in pediatric populations. This research presents OL101:KL47 and O1:KL64 as the predominant combinations among CRKP strains in children in Shanghai, China. The primary carbapenemase gene is KPC in CRKP strains. Additionally, this study found elevated levels of anti-CPS IgG against K47 and K64 K. pneumoniae strains in pediatric patients for the first time. The significant bactericidal activity of these anti-CPS IgGs was confirmed.

Conglomeration of T- and B-Cell Matrix Responses Determines the Potency of Human Bone Marrow Mesenchymal Stromal Cells.

Cell manufacturing facilities need to define the potency of mesenchymal stromal cells (MSCs) as cellular therapeutics in advanced clinical trials or marketing approval. Since MSCs' mechanism of action in humans is not well defined, more than a single functional property of MSCs needs to be captured as a surrogate measure of potency utilizing assay matrix technologies. However, the current limitation is the sole investigation of MSC-mediated T-cell suppression as a surrogate measure of potency. We investigated the effect of MSCs on B-cell matrix responses to be incorporated into the assay matrix potency analytical system. Our results demonstrate that MSCs inhibit B-cell differentiation and block pan-antibody secretion upon activation of B cells in the PBMCs. In contrast, MSCs are inferior in blocking B-cell matrix responses when purified B cells are used. Mechanistic analysis has demonstrated that MSC-mediated inhibition of B-cell matrix responses is non-contact dependent and Tryptophan metabolic pathway plays a major role, akin to the mechanism of MSC-mediated T-cell suppression. MSCs also inhibit both T-cell and B-cell responses when both of these lymphoid populations are concurrently activated in the PBMCs. Secretome analysis of MSC and T/B cell-activated PBMC cocultures identified direct and inverse correlative matrix signatures between humoral antibody isotypes and secretory molecules. The current analysis of the combined and concomitant investigation of T-cell and B-cell matrix responses fulfills the potency assay matrix strategy by incorporating MSCs' interaction with more than a single inflammatory immune responder.

Vaccination in patients with kidney failure: lessons from COVID-19.

Infection is the second leading cause of death in patients with chronic kidney disease (CKD). Adequate humoral (antibody) and cellular (T cell-driven) immunity are required to minimize pathogen entry and promote pathogen clearance to enable infection control. Vaccination can generate cellular and humoral immunity against specific pathogens and is used to prevent many life-threatening infectious diseases. However, vaccination efficacy is diminished in patients with CKD. Premature ageing of the immune system and chronic systemic low-grade inflammation are the main causes of immune alteration in these patients. In the case of SARS-CoV-2 infection, COVID-19 can have considerable detrimental effects in patients with CKD, especially in those with kidney failure. COVID-19 prevention through successful vaccination is therefore paramount in this vulnerable population. Although patients receiving dialysis have seroconversion rates comparable to those of patients with normal kidney function, most kidney transplant recipients could not generate humoral immunity after two doses of the COVID-19 vaccine. Importantly, some patients who were not able to produce antibodies still had a detectable vaccine-specific T cell response, which might be sufficient to prevent severe COVID-19. Correlates of protection against SARS-CoV-2 have not been established for patients with kidney failure, but they are urgently needed to enable personalized vaccination regimens.

Evaluation of AGP, SSA concentration with the relationship of antibody titer in broiler chicken vaccinated with IBD virus

Gumboro or Infectious bursal disease (IBD) is one of the most important diseases in poultry industry. IBD causes economic losses as a result to mortality and reduction in performance and medicine expenses(de S. B. Fróes et al., 2018). IBD is Severe acute disease of 3-6-week-old birds is associated with high mortality, but a less acute or subclinical disease is common in 0-3-week-old birds (Sali, 2019). IBD virus causes lymphoid depletion of the bursa and if this occurs in the first 2 weeks of life, significant depression of the humoral antibody response may result. The current study aims to measurement of antibody titer and acute phase proteins (AGP and SSA) in broiler chickens subjected to the Gumboro vaccine to explore the intensity of the vaccine strain and the response of both the early innate immune response and late humoral immune responses (antibody titers) raised against the vaccine. A handed Ross 308 chicks were divided into three groups, control, intermediate and intermediate plus vaccine. At 10 days old, the chicks were vaccinated and then blood samples collected at 12, 24 hours, and 10 and 15 days.

A Rapid and Sensitive Microfluidics-Based Tool for Seroprevalence Immunity Assessment of COVID-19 and Vaccination-Induced Humoral Antibody Response at the Point of Care.

As of 8 August 2022, SARS-CoV-2, the causative agent of COVID-19, has infected over 585 million people and resulted in more than 6.42 million deaths worldwide. While approved SARS-CoV-2 spike (S) protein-based vaccines induce robust seroconversion in most individuals, dramatically reducing disease severity and the risk of hospitalization, poorer responses are observed in aged, immunocompromised individuals and patients with certain pre-existing health conditions. Further, it is difficult to predict the protection conferred through vaccination or previous infection against new viral variants of concern (VoC) as they emerge. In this context, a rapid quantitative point-of-care (POC) serological assay able to quantify circulating anti-SARS-CoV-2 antibodies would allow clinicians to make informed decisions on the timing of booster shots, permit researchers to measure the level of cross-reactive antibody against new VoC in a previously immunized and/or infected individual, and help assess appropriate convalescent plasma donors, among other applications. Utilizing a lab-on-a-chip ecosystem, we present proof of concept, optimization, and validation of a POC strategy to quantitate COVID-19 humoral protection. This platform covers the entire diagnostic timeline of the disease, seroconversion, and vaccination response spanning multiple doses of immunization in a single POC test. Our results demonstrate that this platform is rapid (~15 min) and quantitative for SARS-CoV-2-specific IgG detection.

Humoral antibody response in Arctic charr (Salvelinus alpinus) against Aeromonas salmonicida ssp. achromogenes following vaccination with a novel autogenous vaccine

The bacterium Aeromonas salmonicida ssp. achromogenes (Asa) causes atypical furunculosis in salmonids that may lead to extensive financial losses in intensive fish farming. The commercially available vaccine commonly used against the ssp. achromogenes in the production of Arctic charr in Iceland has been developed for Atlantic salmon (Salmon salar) against the subspecies salmonicida which causes typical furunculosis, but it has insufficient efficacy in Arctic charr. In response to this, a novel vaccine against Asa in Arctic charr was developed in cooperation with Spanish vaccine company; HIPRA, and the antibody response of Arctic charr against Asa investigated using enzyme-linked immunosorbent assay. Fish used for testing were vaccinated using the novel, monovalent autogenous experimental vaccine and a commercially available vaccine Alpha Ject® 3000 developed for Atlantic salmon that was used as a comparison. The study was conducted in commercial production units where the fish were continually exposed to natural outbreaks of atypical furunculosis. Blood samples were collected from the fish prior to vaccination and thereafter at approximately ten-week intervals in each production unit throughout the production period until the fish reached harvesting size. Fish growth and mortality was recorded throughout the study. The results indicated that both vaccines induced antibody response in fish against Asa antigens and that antibody titers obtained during the first weeks following vaccination were maintained throughout the production period. However, significantly higher antibody titers were observed in fish vaccinated with the experimental novel vaccine and fish mortality was significantly lower in production units containing fish vaccinated with the novel vaccine in comparison to the Alpha Ject 3000® vaccine. These results suggest that the novel vaccine may be a promising candidate for protective immunity against atypical furunculosis caused by Asa in Arctic charr.

N-terminus of flagellin enhances vaccine efficacy against Actinobacillus pleuropneumoniae

BackgroundFlagellin elicits potent immune response and may serve as a vaccine adjuvant. We previously reported that the N-terminus of flagellin (residues 1–99, nFliC) is sufficient for vaccine efficacy enhancement against Pasteurella multocida challenge in chickens. In this study, we futher tested the adjuvancy of nFliC in a subunit vaccine against the pig pathogen Actinobacillus pleuropneumoniae in a mice model. For vaccine formulation, the antigen ApxIIPF (the pore-forming region of the exotoxin ApxII) was combined with nFliC, either through genetic fusion or simple admixture.ResultsImmune analysis showed that nFliC, introduced through genetic fusion or admixture, enhanced both humoral (antibody levels) and cellular (T cell response and cytokine production) immunity. In a challenge test, nFliC increased vaccine protective efficacy to 60–80%, vs. 20% for the antigen-only group. Further analysis showed that, even without a supplemental adjuvant such as mineral salt or oil emulsion, genetically linked nFliC still provided significant immune enhancement.ConclusionsWe conclude that nFliC is a versatile and potent adjuvant for vaccine formulation.

The humoral response and antibodies against SARS-CoV-2 infection.

Two and a half years into the COVID-19 pandemic, we have gained many insights into the human antibody response to the causative SARS-CoV-2 virus. In this Review, we summarize key observations of humoral immune responses in people with COVID-19, discuss key features of infection- and vaccine-induced neutralizing antibodies, and consider vaccine designs for inducing antibodies that are broadly protective against different variants of the SARS-CoV-2 virus.

Biology and molecular pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) remains a global public health infection. Over the past several decades, the basic principles of HBV gene expression and replication as well as the viral and host determinants governing infection outcomes have been largely uncovered. The clinical manifestations of HBV infection vary from an acute and chronic form of the disease. During the acute phase of the infection, the disease manifestations vary from subclinical hepatitis to anicteric hepatitis, icteric hepatitis, and fulminant hepatitis while during the chronic infection, manifest in different from ranging from asymptomatic carrier state to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The clinical outcome of the infection depends upon the level of HBV replication, age at infection, and the immune status of the host. HBV integration into the host genome often serves as a relevant source of hepatitis B surface antigen (HBsAg) expression during chronic infection, possibly triggering an immune response. If HBV is not eliminated, a delicate balance between viral replication and immune defence prevails which may lead to chronic hepatitis and liver cirrhosis. It is generally acknowledged that the humoral antibody response contributes to the clearance of circulating virus particles and the prevention of viral spread within the host while the cellular immune response eliminates infected cells.

The Impact of Black Soldier Fly (Hermetia illucens) as Feed Supplementation on Productive and Physiological Performance of Broiler Chickens

A total of 450 broiler chicks (Ross 308) were used to evaluate the effect of different inclusion levels of a partially black soldier fly (BSF), BSF Powder (BSFP), BSF Puré (BSFPr), and BSF frozen whole larvae (BSFL) on the growth performance, blood parameters, humoral immune response, and intestinal bacterial count of broiler chickens. The chickens were reared from day 1 to 35 and assigned to the control and 9 dietary groups with different forms of BSF (3 replicates per group with 15 chicks). Black soldier fly was included at levels of 2%, 4%, and 6% for BSFP, BSFPr, and BSFL, respectively, in the starter and growing diets. The results indicated similar body weight, weight gain, and the growth rate in chickens fed 4% BSFP, and 2% BSFPr during the experiment. There was a marked difference in blood parameters due to the different BSF forms and included percentages. The humoral immunity antibody titers against the Newcastle disease virus fluctuated among the experimental groups of different ages. Finally, it could be concluded that the BSF can be incorporated at a level of 4% in the form of powder and Puré in a broiler diet which seemed to be adequate to achieve the favorable results in growth performance, blood parameters, immunity, and bacteriological examination. Keywords: Black soldier fly, Insects, Black solidier fly powder, Humoral immune response, Soybean substitution

Global stability of a delayed SARS-CoV-2 reactivation model with logistic growth, antibody immunity and general incidence rate

Mathematical models have been considered as a robust tool to support biological and medical studies of the coronavirus disease 2019 (COVID-19). This new disease is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This paper develop a within-host SARS-CoV-2 dynamics model with logistic growth for healthy epithelial cells, humoral (antibody) immune response and general SARS-CoV-2-target incidence rate. The model is incorporated with four mixed (distributed/discrete) time delays, delay in the formation of latent infected epithelial cells, delay in the formation of active infected epithelial cells, delay in the activation of latent infected epithelial cells, and maturation delay of new SARS-CoV-2 particles. The model is formulated as a system of delay differential equations (DDEs). We establish that the model’s solutions are non-negative and ultimately bounded. We deduce that the model has three equilibria and their existence and stability are perfectly determined by two threshold parameters. We prove the global stability of the model’s equilibria by utilizing the Lyapunov method and applying the LaSalle’s invariance principle. To support and illustrate our theoretical findings we present numerical simulations for the model with a special form of the general incidence rate function. The effect of time delays on the SARS-CoV-2 dynamics is addressed. We observe that increasing time delays values can have the same impact as drug therapies in suppressing viral progression.

Global Stability of a Humoral Immunity COVID-19 Model with Logistic Growth and Delays

The mathematical modeling and analysis of within-host or between-host coronavirus disease 2019 (COVID-19) dynamics are considered robust tools to support scientific research. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of COVID-19. This paper proposes and investigates a within-host COVID-19 dynamics model with latent infection, the logistic growth of healthy epithelial cells and the humoral (antibody) immune response. Time delays can affect the dynamics of SARS-CoV-2 infection predicted by mathematical models. Therefore, we incorporate four time delays into the model: (i) delay in the formation of latent infected epithelial cells, (ii) delay in the formation of active infected epithelial cells, (iii) delay in the activation of latent infected epithelial cells, and (iv) maturation delay of new SARS-CoV-2 particles. We establish that the model’s solutions are non-negative and ultimately bounded. This confirms that the concentrations of the virus and cells should not become negative or unbounded. We deduce that the model has three steady states and their existence and stability are perfectly determined by two threshold parameters. We use Lyapunov functionals to confirm the global stability of the model’s steady states. The analytical results are enhanced by numerical simulations. The effect of time delays on the SARS-CoV-2 dynamics is investigated. We observe that increasing time delay values can have the same impact as drug therapies in suppressing viral progression. This offers some insight useful to develop a new class of treatment that causes an increase in the delay periods and then may control SARS-CoV-2 replication.

Hybrid immunity and vaccine breakthrough lead to robust humoral response and antibodies that effectively neutralize SARS-CoV-2 variants

Abstract Current COVID-19 vaccines significantly reduce overall morbidity and mortality and are vitally important to halting the pandemic; individuals who previously recovered from COVID-19 display enhanced immune responses after vaccination (hybrid immunity) compared to their naïve-vaccinated peers. However, the effects of vaccine breakthrough infections on humoral immune response remain to be determined. Here, we measure neutralizing antibody responses from 104 vaccinated individuals including those with breakthrough infections, hybrid immunity, and no infection history. We find that human immune sera collected after either a breakthrough infection or a vaccination post-natural infection will both broadly neutralize SARS-CoV-2 variants to a similar degree. While age negatively correlates with antibody response after vaccination alone, no such association was found in breakthrough or hybrid immune groups. Together, our data suggest that the additional antigen exposure from natural infection substantially boosts the quantity, quality, and breadth of humoral immune response regardless of whether it occurs before or after vaccination. Supported by grants from the M.J. Murdock Charitable Trust, OHSU Innovative IDEA grant (1018784), NIH (R01AI145835, T32HL083808), and an unrestricted grant from the OHSU Foundation.

High Titers of Low Affinity Antibodies in COVID-19 Patients Are Associated With Disease Severity.

BackgroundAlmost 2 years from the beginning of the coronavirus disease 2019 (COVID-19) pandemic, there is still a lot unknown how the humoral response affects disease progression. In this study, we investigated humoral antibody responses against specific SARS-CoV2 proteins, their strength of binding, and their relationship with COVID severity and clinical information. Furthermore, we studied the interactions of the specific receptor-binding domain (RBD) in more depth by characterizing specific antibody response to a peptide library.Materials and MethodsWe measured specific antibodies of isotypes IgM, IgG, and IgA, as well as their binding strength against the SARS-CoV2 antigens RBD, NCP, S1, and S1S2 in sera of 76 COVID-19 patients using surface plasmon resonance imaging. In addition, these samples were analyzed using a peptide epitope mapping assay, which consists of a library of peptides originating from the RBD.ResultsA positive association was observed between disease severity and IgG antibody titers against all SARS-CoV2 proteins and additionally for IgM and IgA antibodies directed against RBD. Interestingly, in contrast to the titer of antibodies, the binding strength went down with increasing disease severity. Within the critically ill patient group, a positive association with pulmonary embolism, d-dimer, and antibody titers was observed.ConclusionIn critically ill patients, antibody production is high, but affinity is low, and maturation is impaired. This may play a role in disease exacerbation and could be valuable as a prognostic marker for predicting severity.

Humoral antibody response to the first dose of the ChAdOx1 nCoV-19 vaccine in Asian patients undergoing hemodialysis.

Background and objectivesThe immunogenicity of vaccines is known to be attenuated in patients with end‐stage kidney disease due to uremia. Patients on dialysis were excluded from coronavirus disease 2019 (COVID‐19) vaccine trials; thus, the effectiveness of vaccines for this population is unclear. The aim of this study was to explore whether Asian dialysis patients can effectively produce an immune response after being vaccinated with the first dose of the ChAdOx1 nCoV‐19 vaccine.Design setting, participants, and measurementsIn this prospective cohort study, we included Asian hemodialysis patients who received the ChAdOx1 nCoV‐19 vaccine. At 3 weeks after the first dose of vaccination, we assessed the humoral immune response by measuring anti‐SARS‐CoV‐2 S antibody titers. The primary outcome was the seropositive rate following vaccination, defined as an antibody titer greater than or equal to 0.8 U/ml. Factors associated with seropositivity were explored in multivariate logistic regression analyses.ResultsIn total, 434 participants were included. The mean age was 64 years, the mean dialysis vintage was 6 years, and 61% of the participants were men. At a mean time of 22 days from vaccination, 56% of the participants were seropositive. The vast majority (88%) had low antibody titers (< 15 U/ml). The multivariate logistic regression analyses showed that older age (every increase of 10 years, odds ratio [OR] 0.80, 95% CI 0.65–0.98, p = 0.03) was negatively associated with seropositivity and that higher Kt/V (every increase of 0.1, OR 1.14, 95% CI 1.01–1.28, p = 0.03) and higher serum albumin level (every increase of 0.1 g/dl, OR 1.09, 95% CI 1.02–1.18, p = 0.02) were positively associated with seropositivity.ConclusionsIn Asian hemodialysis patients, the seropositive rate was low, and most had low antibody titers after the first dose of the ChAdOx1 nCoV‐19 vaccine. Younger age, better dialysis adequacy, and higher albumin levels were associated with seropositivity.