Immune Donors Research Articles

AI for biofabrication.

Biofabrication is an advanced technology that holds great promise for constructing highly biomimetic in vitro three-dimensional human organs. Such technology would help address the issues of immune rejection and organ donor shortage in organ transplantation, aiding doctors in formulating personalized treatments for clinical patients and replacing animal experiments. Biofabrication typically involves the interdisciplinary application of biology, materials science, mechanical engineering, and medicine to generate large amounts of data and correlations that require processing and analysis. Artificial intelligence (AI), with its excellent capabilities in big data processing and analysis, can play a crucial role in handling and processing interdisciplinary data and relationships and in better integrating and applying them in biofabrication. In recent years, the development of the semiconductor and integrated circuit industries has propelled the rapid advancement of computer processing power. An AI program can learn and iterate multiple times within a short period, thereby gaining strong automation capabilities for a specific research content or issue. To date, numerous AI programs have been applied to various processes around biofabrication, such as extracting biological information, designing and optimizing structures, intelligent cell sorting, optimizing biomaterials and processes, real-time monitoring and evaluation of models, accelerating the transformation and development of these technologies, and even changing traditional research patterns. This article reviews and summarizes the significant changes and advancements brought about by AI in biofabrication, and discusses its future application value and direction.&#xD.

PBMC-engrafted humanized mice models for evaluating immune-related and anticancer drug delivery systems.

Immune-related drug delivery systems (DDSs) in humanized mouse models are at the forefront of cancer research and serve as bridges between preclinical studies and clinical applications. These systems offer unique platforms for exploring new therapies and understanding their interactions with human cells and the immune system. Here, we focus on a DDS and a peripheral blood mononuclear cell (PBMC)-engrafted humanized mouse model that we recently developed, and consider some of the key components, challenges, and applications to advance these systems towards better cancer treatment on the basis of a better understanding of the immune response. Our DDS is unique and has a dual function, an anticancer effect and a capacity to fine-tune the immune reaction. The PBL-NOG-hIL-4-Tg mouse system is superior to other available humanized mouse systems for the development of such multifunctional DDSs because it supports the rapid reconstruction of an individual donor's immunity and avoids the onset of graft-versus-host disease.

Anti-HNA testing of allo-exposed COVID-19 convalescent plasma donors including genetic human neutrophil antigen screening to prevent anti-HNA antibody-mediated transfusion-related acute lung injury.

Transfusion-related acute lung injury caused by antibodies against human neutrophil antigens (HNA) is a serious but rare complication associated with blood transfusion. The presence of such antibodies is most probable in donors with a transfusion/pregnancy history. During the COVID-19 pandemic period convalescent plasma (CP) containing neutralizing antibodies against SARS-CoV-2 was widely used for COVID-19 patients as a therapy in the absence of any treatment. The aim of the study was to work out a simple diagnostic algorithm of anti-HNA testing of allo-exposed CP donors including genetic HNA screening. A total of 457 anti-HLA-negative allo-exposed CP donors were genotyped for HNA-1a/1b, HNA-3a/3b, and HNA-2, and only donors with homozygous HNA-1a/1a; HNA-3b/3b; or HNA-2null genotypes were tested for anti-HNA antibody using LabScreenMulti (One Lambda) and homozygous HNA-1b/1b using the granulocyte immunofluorescence test (GIFT) but verified using LabScreenMulti. Testing of 83 homozygous HNA-3b/3b; HNA-2null; or HNA-1a/1a donors revealed anti-HNA-3a antibody in one case. Testing of 181 HNA-1b/1b donors using GIFT gave 10 ambiguous results verified using LabScreenMulti which confirmed anti-HNA-1a antibody in one case. The frequency of FCGR3B*01 and *04 encoding HNA-1a was 0.34; FCGR3B*02, *03, and *05 encoding HNA-1b-0.66; SLC44A2*01 encoding HNA-3a-0.80; and SLC44A2*02 encoding HNA-3b-0.20. In 3.7% cases the HNA-2null genotype was revealed. Due to applying HNA genotyping as a primary test before anti-HNA antibody testing the serological work was limited only to HNA-homozygous donors revealing two anti-HNA immunized donors. The distribution of HNA genotypes in the cohort was similar to other Caucasian populations.

RAIN: machine learning-based identification for HIV-1 bNAbs

Broadly neutralizing antibodies (bNAbs) are promising candidates for the treatment and prevention of HIV-1 infections. Despite their critical importance, automatic detection of HIV-1 bNAbs from immune repertoires is still lacking. Here, we develop a straightforward computational method for the Rapid Automatic Identification of bNAbs (RAIN) based on machine learning methods. In contrast to other approaches, which use one-hot encoding amino acid sequences or structural alignment for prediction, RAIN uses a combination of selected sequence-based features for the accurate prediction of HIV-1 bNAbs. We demonstrate the performance of our approach on non-biased, experimentally obtained and sequenced BCR repertoires from HIV-1 immune donors. RAIN processing leads to the successful identification of distinct HIV-1 bNAbs targeting the CD4-binding site of the envelope glycoprotein. In addition, we validate the identified bNAbs using an in vitro neutralization assay and we solve the structure of one of them in complex with the soluble native-like heterotrimeric envelope glycoprotein by single-particle cryo-electron microscopy (cryo-EM). Overall, we propose a method to facilitate and accelerate HIV-1 bNAbs discovery from non-selected immune repertoires.

Ad-derived bone marrow transplant induces proinflammatory immune peripheral mechanisms accompanied by decreased neuroplasticity and reduced gut microbiome diversity affecting AD-like phenotype in the absence of Aβ neuropathology

Immune system dysfunction is increasingly recognized as a significant feature that contributes to Alzheimer’s disease (AD) pathogenesis, reflected by alterations in central and peripheral responses leading to detrimental mechanisms that can contribute to the worsening of the disease. The damaging alterations in the peripheral immune system may disrupt the peripheral-central immune crosstalk, implicating the gut microbiota in this complex interaction. The central hypothesis posits that the immune signature inherently harbored in bone marrow (BM) cells can be transferred through allogeneic transplantation, influencing the recipient’s immune system and modulating peripheral, gut, and brain immune responses.Employing a genetically modified mouse model to develop AD-type pathology we found that recipient wild-type (WT) mice engrafted with AD-derived BM, recapitulated the peripheral immune inflammatory donor phenotype, associated with a significant acceleration of cognitive deterioration in the absence of any overt change in AD-type amyloid neuropathology. Moreover, transcriptomic and phylogenetic 16S microbiome analysis evidence on these animals revealed a significantly impaired expression of genes associated with synaptic plasticity and neurotransmission in the brain and reduced bacteria diversity, respectively, compared to mice engrafted with WT BM.This investigation sheds light on the pivotal role of the peripheral immune system in the brain-gut-periphery axis and its profound potential to shape the trajectory of AD.In summary, this study advances our understanding of the complex interplay among the peripheral immune system, brain functionality, and the gut microbiome, which collectively influence AD onset and progression.

RAIN: a Machine Learning-based identification for HIV-1 bNAbs.

Broadly neutralizing antibodies (bNAbs) are promising candidates for the treatment and prevention of HIV-1 infection. Despite their critical importance, automatic detection of HIV-1 bNAbs from immune repertoire is still lacking. Here, we developed a straightforward computational method for Rapid Automatic Identification of bNAbs (RAIN) based on Machine Learning methods. In contrast to other approaches using one-hot encoding amino acid sequences or structural alignment for prediction, RAIN uses a combination of selected sequence-based features for accurate prediction of HIV-1 bNAbs. We demonstrate the performance of our approach on non-biased, experimentally obtained sequenced BCR repertoires from HIV-1 immune donors. RAIN processing leads to the successful identification of novel HIV-1 bNAbs targeting the CD4-binding site of the envelope glycoprotein. In addition, we validate the identified bNAbs using in vitro neutralization assay and we solve the structure of one of them in complex with the soluble native-like heterotrimeric envelope glycoprotein by single-particle cryo-electron microscopy (cryo-EM). Overall, we propose a method to facilitate and accelerate HIV-1 bNAbs discovery from non-selected immune repertoires.

Acute myeloid leukaemia relapse after allogeneic haematopoietic stem cell transplantation: Mechanistic diversity and therapeutic directions.

Emerging biological and clinical data, along with advances in new technologies, have exposed the mechanistic diversity in post-haematopoietic stem cell transplant (HCT) relapse. Post-HCT relapse mechanisms are relevant for guiding sophisticated selection of therapeutic interventions and identification of areas for further research. Clonal evolution and emergence of resistant leukemic strains is a common mechanism shared by relapse post-chemotherapy and post-HCT, other mechanisms such as leukemic immune escape and donor T cell exhaustion are unique entities to post-HCT relapse. Due to diversity in the mechanisms behind post-HCT relapse, the subsequent clinical approach relies on clinician discretion, rather than objective evidence. Lack of standardized selection based on post-HCT relapse mechanism(s) could be a contributing factor to observed poor outcomes. Therapeutic strategies including donor lymphocyte infusion (DLI), second transplant, immunotherapies, hypomethylating agents, and targeted strategies are supported options and efficacy may be enhanced when post-HCT AML relapse mechanism is established and guides treatment selection. This review aims, through compilation of supporting studies, to describe mechanisms of post-HCT relapse and their implications for subsequent treatment selection and inspiration for future research.

The role of smart polymeric biomaterials in bone regeneration: a review.

Addressing critical bone defects necessitates innovative solutions beyond traditional methods, which are constrained by issues such as immune rejection and donor scarcity. Smart polymeric biomaterials that respond to external stimuli have emerged as a promising alternative, fostering endogenous bone regeneration. Light-responsive polymers, employed in 3D-printed scaffolds and photothermal therapies, enhance antibacterial efficiency and bone repair. Thermo-responsive biomaterials show promise in controlled bioactive agent release, stimulating osteocyte differentiation and bone regeneration. Further, the integration of conductive elements into polymers improves electrical signal transmission, influencing cellular behavior positively. Innovations include advanced 3D-printed poly (l-lactic acid) scaffolds, polyurethane foam scaffolds promoting cell differentiation, and responsive polymeric biomaterials for osteogenic and antibacterial drug delivery. Other developments focus on enzyme-responsive and redox-responsive polymers, which offer potential for bone regeneration and combat infection. Biomaterials responsive to mechanical, magnetic, and acoustic stimuli also show potential in bone regeneration, including mechanically-responsive polymers, magnetic-responsive biomaterials with superparamagnetic iron oxide nanoparticles, and acoustic-responsive biomaterials. In conclusion, smart biopolymers are reshaping scaffold design and bone regeneration strategies. However, understanding their advantages and limitations is vital, indicating the need for continued exploratory research.

Hyperimmune Globulins for the Management of Infectious Diseases

This review is focused on the use of hyperimmune globulin therapy to treat some infectious diseases of viral or bacterial origin. Despite the introduction of antibiotics and vaccines, plasma immunoglobulin therapy from whole blood donation can still play a key role. These treatments provide passive transfer of high-titer antibodies that either reduces the risk or the severity of the infection and offer immediate but short-term protection against specific diseases. Antibody preparations derived from immunized human donors are commonly used for the prophylaxis and treatment of rabies, hepatitis A and B viruses, varicella-zoster virus, and pneumonia caused by respiratory syncytial virus, Clostridium tetani, Clostridium botulinum. The use of hyperimmune globulin therapy is a promising challenge, especially for the treatment of emerging viral infections for which there are no specific therapies or licensed vaccines.

Stories behind the cover

To celebrate the 1st Anniversary of Portal Hypertension & Cirrhosis (PH&C), we would like to tell the story behind the cover images and extend our sincere thanks to all the authors, reviewers, editorial board members, as well as to the cover illustrator for their tremendous contribution to our journal over the past year. For the inaugural cover image, the vasculature of the portal venous system was designed to resemble the “Silk Road” that linked the East and the West.1 Hepatologists, gastroenterologists, interventional radiologists, surgeons, pathologists, researchers, and other specialists involved, regardless of the country or region, are connected to collaborate on the best science and practice of portal hypertension and cirrhosis. The cover image is a true reflection of the core value of PH&C: to create a community that commits to pursuing innovative research, integrating multidisciplinary practice, and delivering patient-centered care. The cover image for the second issue depicts the transformation of a spleen into a functioning liver realized by tissue engineering.2 Liver transplantation is the most effective treatment for end-stage liver disease; however, organ shortage has been one of the major concerns across the globe. In addition to reviewing the current development and challenges of tissue engineering and its feasibility and superiority in organ transformation,2 the authors' enduring work solved immune rejection and cell donors and exploited the direct reprogramming technique to turn a spleen into a functional liver.3, 4 The cover image for the third issue described the benefit of antibiotic prophylaxis for patients with early cirrhosis and upper gastrointestinal bleeding.5 This updated meta-analysis on 18 studies and 3180 cirrhotic patients found that antibiotic prophylaxis reduced mortality at 6 weeks, risk of infection, and infection-related mortality.5 The idea of this study reminded the illustrators of Butterflies in Love with Flowers, a legendary song poetry in Chinese culture. The painting metaphorically represented the stomach and bleeding as a vase and red flowers while prophylactic antibiotic treatment as a butterfly. Traditional Chinese medicine has a long and rich tradition of treating liver diseases with its distinctive philosophy and clinical methods, dating back to more than 2000 years ago.6 As illustrated in the cover story of the fourth issue, the mechanisms of several traditional Chinese medicine active ingredients and compounds in the treatment of liver fibrosis via hepatic stellate cells (HSCs), including inhibiting HSCs activation, regulating the inactivation of HSCs, and promoting the death of activated HSCs were reviewed.7 Many oriental elements were displayed on the cover, such as Chinese herbs and the Yin-Yang and Five-Element theory in the philosophy of traditional Chinese medicine. As moving forward into our second year, we look forward to continuing working together to provide healthcare professionals with cutting-edge academic advances and the latest insights in the field of portal hypertension and cirrhosis. We believe that with your constant support, PH&C will keep growing into a highly successful international journal step-by-step (Figure 1). None. The author declares no conflict of interest. None.

A Novel In Vivo Active Pemphigus Model Targeting Desmoglein1 and Desmoglein3: A Tool Representing All Pemphigus Variants.

Background: Pemphigus is a life-threatening blistering autoimmune disease. Several forms, characterized by the presence of autoantibodies against different autoantigens, have been described. In Pemphigus Vulgaris (PV), autoantibodies target the cadherin Desmoglein 3 (DSG3), while in Pemphigus foliaceous (PF) autoantibodies target the cadherin Desmoglein 1 (DSG1). Another variant, mucocutaneous Pemphigus, is characterized by the presence of IgG against both DSG1 and DSG3. Moreover, other forms of Pemphigus characterized by the presence of autoantibodies against other autoantigens have been described. With regard to animal models, one can distinguish between passive models, where pathological IgG are transferred into neonatal mice, and active models, where B cells deriving from animals immunized against a specific autoantigen are transferred into immunodeficient mice that develop the disease. Active models recreate PV and a form of Pemphigus characterized by the presence of IgG against the cadherin Desmocollin 3 (DSC3). Further approaches allow to collect sera or B/T cells from mice immunized against a specific antigen to evaluate the mechanisms underlying the onset of the disease. Objective: To develop and characterize a new active model of Pemphigus where mice express auto antibodies against either DSG1 alone, or DSG1 and DSG3, thereby recapitulating PF and mucocutaneous Pemphigus, respectively. In addition to the existing models, with the active models reported in this work, it will be possible to recapitulate and mimic the main forms of pemphigus in adult mice, thus allowing a better understanding of the disease in the long term, including the benefit/risk ratio of new therapies. Results: The new DSG1 and the DSG1/DSG3 mixed models were developed as proposed. Immunized animals, and subsequently, animals that received splenocytes from the immunized donors produce a high concentration of circulating antibodies against the specific antigens. The severity of the disease was assessed by evaluating the PV score, evidencing that the DSG1/DSG3 mixed model exhibits the most severe symptoms among those analyzed. Alopecia, erosions, and blistering were observed in the skin of DSG1, DSG3 and DSG1/DSG3 models, while lesions in the mucosa were observed only in DSG3 and DSG1/DSG3 animals. The effectiveness of the corticosteroid Methyl-Prednisolone was evaluated in the DSG1 and DSG1/DSG3 models, that showed only partial responsiveness.

Determination of information, attitudes and behaviors about immune plasma donation of individuals diagnosed with COVID-19

Background: Immune plasma therapy is an effective solution in pandemic conditions until an effective and proven treatment is found. In this process, a large number of volunteers who accept to be immune plasma donors are needed. Therefore, being informed about the hesitation of the donors regarding plasma donation will be a guide for voluntary donor recruitment. The aim of this research was to evaluate the knowledge, attitudes, and behaviors of individuals diagnosed with Covid 19 about immune plasma donation. Materials and Methods: This is cross-sectional research. Between January and May 2021, individuals between the ages of 18 and 60 who received treatment in a training and research hospital's Covid 19 clinics were included. Results: The mean age of the participants was 43.79±11.47 years, 45.5% (n=100) female and 55% (n=120) male. 46.36% of the participants are considering becoming immune plasma donors. One of the factors that prevent being an immune plasma donor is the thought that "it may negatively affect my health. "Half of the participants do not know whether sufficient immune plasma donation is made in the country. Conclusions: The health care system needs to be strengthened about immune plasma donation during the pandemic process. In addition, efforts should be made to eliminate the hesitations of the public about donations.

Three doses of a recombinant conjugated SARS-CoV-2 vaccine early after allogeneic hematopoietic stem cell transplantation: predicting indicators of a high serologic response-a prospective, single-arm study.

Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients must be vaccinated against SARS-CoV-2 as quickly as possible after transplantation. The difficulty in obtaining recommended SARS-CoV-2 vaccines for allo-HSCT recipients motivated us to utilize an accessible and affordable SARS-CoV-2 vaccine with a recombinant receptor-binding domain (RBD)-tetanus toxoid (TT)-conjugated platform shortly after allo-HSCT in the developing country of Iran. This prospective, single-arm study aimed to investigate immunogenicity and its predictors following a three-dose SARS-CoV-2 RBD-TT-conjugated vaccine regimen administered at 4-week (±1-week) intervals in patients within 3-12 months post allo-HSCT. An immune status ratio (ISR) was measured at baseline and 4 weeks (±1 week) after each vaccine dose using a semiquantitative immunoassay. Using the median ISR as a cut-off point for immune response intensity, we performed a logistic regression analysis to determine the predictive impact of several baseline factors on the intensity of the serologic response following the third vaccination dose. Thirty-six allo-HSCT recipients, with a mean age of 42.42 years and a median time of 133 days between hematopoietic stem cell transplant (allo-HSCT) and the start of vaccination, were analyzed. Our findings, using the generalized estimating equation (GEE) model, indicated that, compared with the baseline ISR of 1.55 [95% confidence interval (CI) 0.94 to 2.17], the ISR increased significantly during the three-dose SARS-CoV-2 vaccination regimen. The ISR reached 2.32 (95% CI 1.84 to 2.79; p=0.010) after the second dose and 3.87 (95% CI 3.25 to 4.48; p=0.001) after the third dose of vaccine, reflecting 69.44% and 91.66% seropositivity, respectively. In a multivariate logistic regression analysis, the female sex of the donor [odds ratio (OR) 8.67; p=0.028] and a higher level donor ISR at allo-HSCT (OR 3.56; p=0.050) were the two positive predictors of strong immune response following the third vaccine dose. No serious adverse events (i.e., grades 3 and 4) were observed following the vaccination regimen. We concluded that early vaccination of allo-HSCT recipients with a three-dose RBD-TT-conjugated SARS-CoV-2 vaccine is safe and could improve the early post-allo-HSCT immune response. We further believe that the pre-allo-HSCT SARS-CoV-2 immunization of donors may enhance post-allo-HSCT seroconversion in allo-HSCT recipients who receive the entire course of the SARS-CoV-2 vaccine during the first year after allo-HSCT.

Review and assessment of the donor safety among plasma donors.

Review and assessment of the donor safety among plasma donors.

Cross-Reactive Profile Against Two Conserved Coronavirus Antigens in Sera from SARS-CoV-2 Hybrid and Vaccinated Immune Donors.

Since the beginning of the pandemic, the pre-existing immunity against SARS-CoV-2 has been postulated as one possible cause of asymptomatic infections. Later, various works reported that pre-existing immune response against the two structural conserved antigens: S2 subunit and the nucleocapsid protein, were associated to some level of asymptomatic profile in infected individuals. To explore the Ab background against these two antigens, in the context of vaccine-elicited and hybrid (natural infection plus vaccination induced) immunity of SARS-CoV-2, in this work, we tested sera from inactivated vaccine-immunized donors and from vaccinated and subsequent natural infected donors upon the Omicron variant wave in Guangdong province, China. Serum samples were collected from 27 COVID-19 convalescent, 25 SARS-CoV-2 vaccinated, and 10 negative donors. The IgG cross-reactivity response against these two antigens from another relevant human coronavirus (HCoV) was also evaluated. The findings indicate that IgG response against S2 and N protein was particularly higher in sera with hybrid immunity. The cross-reactive Abs were more significant against SARS-CoV-1, while a wide cross-reactivity was detected for N antigen for one human Alpha coronavirus HCoV-229E even in the negative control samples. The presence of cross-reactive Abs against the two conserved antigens N and S2, particularly in the context of hybrid immunity, could pave the way for future boosted vaccines carrying these conserved regions.

Do CAR-T and Allogeneic Stem Cell Transplant Both Have a Place in Lymphoid Neoplasms?

Allogeneic stem cell transplantation (allo-SCT) represented the first immunotherapy to treat hematologic malignancies: it has been considered as a cure for the disease and never as an approach to extend the life of patients. The success of allo-SCT derives both from the ability to treat patients with intensive chemoradiotherapy and from the potent graft-versus-leukemia effects mediated by donor immunity. Although considerable progress has been made in the last years, significant barriers still remain in the form of disease relapse, graft-versus-host disease, infectious complications, and regimen-related toxicities. Moreover, the treatment of hematologic malignancies, particularly acute lymphoblastic leukemia and certain forms of lymphomas, has been revolutionized by the commercial introduction of genetically modified autologous T-lymphocyte therapy (CAR-T). Our review discusses current standards and the shifting paradigms in the indications for allo-SCT and the role of CAR-T cell therapy for lymphoid neoplasms.

Formation of collective immunity against a new coronavirus infection COVID-19 in blood donors

Introduction. The new coronavirus infection COVID-19, fi rst detected at the end of 2019 in the Chinese city of Wuhan, caused a worldwide pandemic. High mortality among people with chronic diseases, a high frequency of the severe form of the disease, and an unspecifi ed number of asymptomatic carriers are all causes for heavy burden on the healthcare system, including the blood bank service.Aim – to assess the SARS-CoV-2 antibody formation in blood donors.Materials and methods. The research included test results for 12,314 blood samples of donors who donated blood during 04.29.2020 – 08.04.2021 at the National Medical Research Center for Hematology (Russia). Anti-RBD-SARS IgG were tested by «SARS-CoV-2-IgG-ELISA», manufactured by the National Medical Research Center for Hematology, LLC «HEMA» (Russia).Results. Among 12,314 blood samples from donors, 3,219 (26.14 %) were positive for antibodies to SARS-CoV-2. Antibodies detection rate increased from 8.52 to 58.09 % during the observation period. For representative evaluation of donors’ anti-SARS antibodies growth profi le, the results of detection were analyzed within two-week periods (including holidays). This approach made it possible to avoid counting the same donor twice. In the profi le of the growth of collective immunity in donors, two periods were identifi ed: May – November 2020 and November 2020 – April 2021. The period of May – November 2020 proved no signifi cant change in antibodies detection in donors. Detection rate was stable at about 15 % (13.10–16.24 %). The second period, from November 2020 to April 2021, demonstrated sustainable growth of this parameter from 16.20 to 58.09 %. This is likely due to the start of the second wave of COVID-19 in Russia (starting from November 2020) and an active campaign for mass vaccination that started in December 2020. To assess the true rate of increase of specifi c immunity in donors, the frequency of primary detection of antibodies to SARS-CoV-2 in donors in relation to those donors in whom antibodies were detected earlier was analyzed. The contribution of cases of primary detection of antibodies to SARS-CoV-2 was wave-like and corresponded to the epidemiological situation.Conclusion. An increase in the frequency of detection of antiviral antibodies in gratuitous blood donors was found during the spread of the second wave of COVID-19 and the n the beginning of mass vaccination. The increase in the overall frequency of antibody detection was due to donors with newly and re-detected antibodies. The surge in the frequency of primary detection of antibodies in blood donors corresponded to the second wave of infection.

A novel method for in vitro culture and expansion of nonhuman primate B cells

BackgroundGiven the role of B cells in sensitization and antibody-mediated rejection pathogenesis, the ability to identify, isolate, and study B cells in vitro is critical for understanding these processes and developing novel therapeutics. While in vivo nonhuman primate models have been used to this end, an in vitro nonhuman primate model of B cell activation and proliferation has not been developed. MethodsCD20+ B cells and CD3+ T cells were isolated using magnetic bead separation from the peripheral blood of naive and skin allograft sensitized nonhuman primates. Allogeneic B and T cells were co-cultured in plates pre-coated with murine stromal cells engineered to express human CD40L and stimulated with cytokines. Cells and supernatants were harvested every 2 days for immune phenotyping and donor specific antibody quantification by flow cytometry. ResultsThe optimized culture system consisted of MS40L cells co-cultured with B and allogenic T cells and stimulated with cytokines. This culture system resulted in increased memory cells and plasmablasts over time compared to other culture systems. Comparison of culture of naïve and sensitized nonhuman primate samples revealed faster B cell exhaustion and marginally increased plasmablast differentiation in sensitized culture. Donor-specific antibody production was not observed in either culture group. ConclusionsThis study describes the first in vitro nonhuman primate model of B cell activation and proliferation using both naïve and allosensitized samples. This model provides an opportunity for exploration of B cell mechanisms and novel therapeutics and is a preliminary step in the development of an in vitro germinal center model.

SARS-CoV-2 and Immunity: Natural Infection Compared with Vaccination

Recently, the protective and/or pathological role of virus-specific T cells in SARS-CoV-2 infection has been the focus of many studies. We investigated the anti-spike IgG levels and SARS-CoV-2-specific T cells in 125 donors (90 vaccinated with four different vaccine platforms, 16 individuals with a previous natural infection, and 19 not vaccinated donors who did not report previous SARS-CoV-2 infections). Our data show that anti-spike IgG titers were similar between naturally infected subjects and those vaccinated with adenoviral vector vaccines. Of note, all immunized donors produced memory CD4+ and/or CD8+ T cells. A sustained polyfunctionality of SARS-CoV-2-specific T cells in all immunized donors was also demonstrated. Altogether, our data suggest that the natural infection produces an overall response like that induced by vaccination. Therefore, this detailed immunological evaluation may be relevant for other vaccine efforts especially for the monitoring of novel vaccines effective against emerging virus variants.

Prevalence of hepatitis B surface antigen (HBsAg) in blood donor population in Bosnia and Herzegovina: Impact of the pre-donation questionnaire implementation and mandatory hepatitis B virus (HBV) vaccination schedule-20 years' experience of the University Clinical Hospital Mostar.

Currently, there are limited data on the prevalence of HBsAg in Bosnia and Herzegovina. This study aimed to evaluate the trend of HBsAg prevalence during a period of 20 years in relation to the implementation of pre-donation questionnaires based on parenteral and sexual risk factors and mandatory HBV vaccination. This is a retrospective analysis performed on 67,336 blood donors at the University Clinical Hospital Mostar during three distinct periods: before introducing of mandatory HBV vaccination and pre-donation blood donor questionnaires (1998-2002); after introducing of pre-donation blood donor questionnaires, but without mandatory immunized blood donors (2004-2008); and after introducing of mandatory pre-donation blood donor questionnaires and mandatory vaccination (2015-2019). According to implementation of mandatory pre-donation blood donor questionnaires and mandatory HBV vaccination the prevalence of HBsAg significantly decreased among blood donors in all three studied periods of time (0.303% in 1998-2002, 0.236% in 2004-2008, and 0.021% in 2015-2019; P<0.001). Out of 67,336 tested donors, there were 98 (0.145%) HBsAg-positive donors during analysed periods, with a mean age of 34.76±11.37 years. The mean age of HBsAg-positive donors was 30.72±10.40, 37.56±10.13, and 47.28±12.14) in the 1998-2002, 2004-2008, and 2015-2019 periods, respectively (P<0.001). This study clearly shows a decreased rate of HBV infections among blood donors with respect to implementation of the HBV vaccination schedule and mandatory pre-donation blood donor questionnaires based on parenteral and sexual risk factors.