Influenza Antigens Research Articles

Diagnostic accuracy of SARS-CoV-2 and influenza antigen test in Omicron age in hospital emergency department: real-life analysis during 2023

Diagnostic accuracy of SARS-CoV-2 and influenza antigen test in Omicron age in hospital emergency department: real-life analysis during 2023

Steered molecular dynamics simulation as a post-process to optimize the iBRAB-designed Fab model.

Therapeutic monoclonal antibodies are an effective method of treating acute infectious diseases. However, knowing which of the produced antibodies in the vast number of human antibodies can cure the disease requires a long time and advanced technology. The previously introduced iBRAB method relies on studied antibodies to design a broad-spectrum antibody capable of neutralizing antigens of many different Influenza A viral strains. To evaluate the antigen-binding fragment as an applicable drug, the therapeutic antibody profiles providing guidelines collected from clinically staged therapeutic antibodies were used to access different measurements. Although the evaluated values were within an accepted range, the modification in the amino acid sequence is required for better properties. Thus, using the steered molecular dynamics(SMD) simulation to determine the binding capacity of amino acids in the functional region, the profile of interacted amino acids of Fab with the antigen was established for modified reference. As a result, the model was modified with amino acids elimination at positions 96-97 in the heavy chain and 26-27, 91, 96-97, and 102-103 in the light chain, which has better Therapeutic Antibody Profiler evaluations than the original designation. Thus again, SMD simulation is a promising computational approach for post-modification in rational drug design.

Efficacy of the H7N9 vaccine as a candidate for the Korean avian influenza antigen bank

The avian influenza A virus (H7N9), first detected in China in 2013, is a zoonotic virus that remains persistent in bird populations despite a decline in human cases owing to control measures. Therefore, this study aimed to develop a vaccine as one preventive strategy in anticipation of the potential entry of H7N9 into Korea. Using the hemagglutinin and neuraminidase consensus sequences of H7N9 from 2018–2019, a recombinant H7N9 vaccine, rgAPQAH7N9, was developed, and its protective efficacy in specific pathogen-free chickens was evaluated. The rgAPQAH7N9 vaccine exhibited proliferation in eggs and demonstrated high immunogenicity, with a hemagglutination inhibition titer of 9.3 log2. Furthermore, the vaccine provided complete protection, as vaccinated chickens did not exhibit clinical signs or viral shedding. Moreover, when the rgAPQAH7N9 vaccine was boosted, the resulting immunity was long-lasting, with hemagglutination inhibition titers > 7 log2 persisting after 6 months. Therefore, the rgAPQAH7N9 vaccine virus may be considered a potential candidate for inclusion in the avian influenza antigen bank to ensure preparedness for emergency vaccination in poultry.

Single-Cell Antigen Receptor Sequencing in Pigs with Influenza.

Understanding the pulmonary adaptive immune system of pigs is important as respiratory pathogens present a major challenge for swine producers and pigs are increasingly used to model human pulmonary diseases. Single-cell RNA sequencing (scRNAseq) has accelerated the characterization of cellular phenotypes in the pig respiratory tract under both healthy and diseased conditions. However, combining scRNAseq with recovery of paired T cell receptor (TCR) α and β chains as well as B cell receptor (BCR) heavy and light chains to interrogate their repertoires has not to our knowledge been demonstrated for pigs. Here, we developed primers to enrich porcine TCR α and β chains along with BCR κ and λ light chains and IgM, IgA, and IgG heavy chains that are compatible with the 10x Genomics VDJ sequencing protocol. Using these pig-specific assays, we sequenced the T and B cell receptors of cryopreserved lung cells from CD1D-expressing and -deficient pigs after one or two infections with influenza A virus (IAV) to examine whether natural killer T (NKT) cells alter pulmonary TCR and BCR repertoire selection. We also performed paired single-cell RNA and receptor sequencing of FACS-sorted T cells longitudinally sampled from the lungs of IAV-vaccinated and -infected pigs to track clonal expansion in response to IAV exposure. All pigs presented highly diverse repertoires. Pigs re-exposed to influenza antigens from either vaccination or infection exhibited higher numbers of expanded CD4 and CD8 T cell clonotypes with activated phenotypes, suggesting potential IAV reactive T cell populations. Our results demonstrate the utility of high throughput single-cell TCR and BCR sequencing in pigs.

Cytomegalovirus vaccine vector-induced effector memory CD4 + T cells protect cynomolgus macaques from lethal aerosolized heterologous avian influenza challenge

An influenza vaccine approach that overcomes the problem of viral sequence diversity and provides long-lived heterosubtypic protection is urgently needed to protect against pandemic influenza viruses. Here, to determine if lung-resident effector memory T cells induced by cytomegalovirus (CMV)-vectored vaccines expressing conserved internal influenza antigens could protect against lethal influenza challenge, we immunize Mauritian cynomolgus macaques (MCM) with cynomolgus CMV (CyCMV) vaccines expressing H1N1 1918 influenza M1, NP, and PB1 antigens (CyCMV/Flu), and challenge with heterologous, aerosolized avian H5N1 influenza. All six unvaccinated MCM died by seven days post infection with acute respiratory distress, while 54.5% (6/11) CyCMV/Flu-vaccinated MCM survived. Survival correlates with the magnitude of lung-resident influenza-specific CD4 + T cells prior to challenge. These data demonstrate that CD4 + T cells targeting conserved internal influenza proteins can protect against highly pathogenic heterologous influenza challenge and support further exploration of effector memory T cell-based vaccines for universal influenza vaccine development.

Evaluation of Efficacy of Surface Coated versus Encapsulated Influenza Antigens in Mannose-Chitosan Nanoparticle-Based Intranasal Vaccine in Swine.

This study focuses on the development and characterization of an intranasal vaccine platform using adjuvanted nanoparticulate delivery of swine influenza A virus (SwIAV). The vaccine employed whole inactivated H1N2 SwIAV as an antigen and STING-agonist ADU-S100 as an adjuvant, with both surface adsorbed or encapsulated in mannose-chitosan nanoparticles (mChit-NPs). Optimization of mChit-NPs included evaluating size, zeta potential, and cytotoxicity, with a 1:9 mass ratio of antigen to NP demonstrating high loading efficacy and non-cytotoxic properties suitable for intranasal vaccination. In a heterologous H1N1 pig challenge trial, the mChit-NP intranasal vaccine induced cross-reactive sIgA antibodies in the respiratory tract, surpassing those of a commercial SwIAV vaccine. The encapsulated mChit-NP vaccine induced high virus-specific neutralizing antibody and robust cellular immune responses, while the adsorbed vaccine elicited specific high IgG and hemagglutinin inhibition antibodies. Importantly, both the mChit-NP vaccines reduced challenge heterologous viral replication in the nasal cavity higher than commercial swine influenza vaccine. In summary, a novel intranasal mChit-NP vaccine platform activated both the arms of the immune system and is a significant advancement in swine influenza vaccine design, demonstrating its potential effectiveness for pig immunization.

Patients with juvenile idiopathic arthritis have decreased clonal diversity in the CD8+ T cell repertoire response to influenza vaccination.

Recurrent exposures to a pathogenic antigen remodel the CD8+ T cell compartment and generate a functional memory repertoire that is polyclonal and complex. At the clonotype level, the response to the conserved influenza antigen, M158-66 has been well characterized in healthy individuals, but not in patients receiving immunosuppressive therapy or with aberrant immunity, such as those with juvenile idiopathic arthritis (JIA). Here we show that patients with JIA have a reduced number of M158-66 specific RS/RA clonotypes, indicating decreased clonal richness and, as a result, have lower repertoire diversity. By using a rank-frequency approach to analyze the distribution of the repertoire, we found several characteristics of the JIA T cell repertoire to be akin to repertoires seen in healthy adults, including an amplified RS/RA-specific antigen response, representing greater clonal unevenness. Unlike mature repertoires, however, there is more fluctuation in clonotype distribution, less clonotype stability, and more variable IFNy response of the M158-66 specific RS/RA clonotypes in JIA. This indicates that functional clonal expansion is altered in patients with JIA on immunosuppressive therapies. We propose that the response to the influenza M158-66 epitope described here is a general phenomenon for JIA patients receiving immunosuppressive therapy, and that the changes in clonal richness and unevenness indicate a retarded and uneven generation of a mature immune response.

Repeated vaccination does not appear to significantly weaken the protective effect of influenza vaccine in the elderly: A test-negative case-control study in China

BackgroundThe impact of repeated influenza vaccination on vaccine effectiveness has been a topic of debate. Conducting more multinational, multicenter studies in different influenza seasons is crucial for a better understanding of this issue. There is a lack of comprehensive related research reports in China. MethodsUsing the Regional Health Information Platform, we conducted a test-negative case-control study to evaluate the impact of repeated vaccination on the prevention of laboratory-confirmed influenza in individuals aged 60 and above in Ningbo during four influenza seasons from 2018–19 to 2021–22. Influenza-positive cases and negative controls were matched in a 1:1 ratio based on the visiting hospital and the date of influenza testing. Propensity score adjustment and multivariable logistic regression were used to estimate risk and address confounding effects. ResultsDuring the study period, a total of 30,630 elderly patients underwent influenza virus nucleic acid or antigen testing. After exclusions, we included 1976 cases of influenza-positive and 1976 cases of influenza-negative controls. Multivariable logistic regression analysis revealed that individuals receiving the vaccine in two consecutive seasons did not exhibit a significantly increased risk of influenza illness compared to those receiving the vaccine only in the current season (adjusted odds ratio: 1.22, 95% confidence interval: 0.94–1.58). However, the risk of influenza illness was found to be elevated in individuals who received the vaccine only in the previous season (adjusted odds ratio: 1.56, 95% confidence interval: 1.15–2.10) and even further elevated in those who had not received the vaccine in either of the consecutive two seasons (adjusted odds ratio: 3.39, 95% confidence interval: 2.80–4.09). ConclusionsRegardless of the vaccination history in the previous season, receiving the current season influenza vaccine is the best choice for the elderly population. Our study supports the initiative to vaccinate elderly individuals against influenza annually.

Tissue-specific sex differences in pediatric and adult immune cell composition and function.

Sex-based differences in immune cell composition and function can contribute to distinct adaptive immune responses. Prior work has quantified these differences in peripheral blood, but little is known about sex differences within human lymphoid tissues. Here, we characterized the composition and phenotypes of adaptive immune cells from male and female ex vivo tonsils and evaluated their responses to influenza antigens using an immune organoid approach. In a pediatric cohort, female tonsils had more memory B cells compared to male tonsils direct ex vivo and after stimulation with live-attenuated but not inactivated vaccine, produced higher influenza-specific antibody responses. Sex biases were also observed in adult tonsils but were different from those measured in children. Analysis of peripheral blood immune cells from in vivo vaccinated adults also showed higher frequencies of tissue homing CD4 T cells in female participants. Together, our data demonstrate that distinct memory B and T cell profiles are present in male vs. female lymphoid tissues and peripheral blood respectively and suggest that these differences may in part explain sex biases in response to vaccines and viruses.

Synthesis of Rupestonic Acid L-Ephedrine Derivatives with Preliminary In vitro Anti-influenza Viral Activity.

Influenza virus is a kind of RNA virus. Nowadays, the high incidence of influenza and the morbidity and mortality of epidemic influenza are substantial. It has been reported that one hundred million people in the world are infected with influenza viruses, and two hundred and fifty thousand to five hundred thousand people die from the flu per year. In 2021, the number of infected persons in China was reported to be 654,700, and 0.07% of the infected persons died. The flu has caused a serious threat to human survival. Although several drugs, such as Zanamivir, Oseltamivir, Peramivir, and Laninamivir, have been used in clinics for the treatment of the influenza virus, there are some shortcomings of these drugs. The strain of influenza H5N1 (avian influenza) has been found to resist the effective drug Oseltamivir. Thus, there is an urgent demand to discover new influenza virus inhibitors to overcome the emergence of influenza antigens. This study aimed to develop new influenza virus inhibitors based on the rupestonic acid parent core. The rupestonic acid L-ephedrine ester (A) and rupestonic acid L-ephedrine complex (B) were synthesized in this work for the development of influenza virus inhibitors. The target compounds were synthesized using rupestonic acid and L-ephedrine as starting materials. Their structures were characterized by 1H NMR and 13C NMR, and the purity was determined by HPLC. Then, their preliminary in vitro influenza activity was evaluated using Oseltamivir as a reference drug. The results showed that the synthesized rupestonic acid L-ephedrine derivatives A and B were more potent influenza virus inhibitors against the strains of A/PR/8/34 (H1N1) and A/FM/1/47 (H1N1) with the IC50 values of 51.0, 51.0 μM and 441.0, 441.0 μM, respectively, than that of rupestonic acid. By comparing the IC50 of compounds A and B, compound A can be regarded as a very promising lead compound for the development of influenza virus inhibitors. The rupestonic acid L-ephedrine ester (A) and rupestonic acid L-ephedrine complex (B) were synthesized and characterized using 1H NMR and 13C NMR. Moreover, their purity was determined by HPLC. Both compounds A and B exhibited more potent activities against the strains of A/PR/8/34 (H1N1) and A/FM/1/47 (H1N1) than rupestonic acid. Compound A can be regarded as a very promising lead compound for the development of influenza virus inhibitors. Based on these results, more rupestonic acid derivatives will be designed and synthesized in the future for the development of influenza virus inhibitors.

Cellular and Molecular Immunity to Influenza Viruses and Vaccines.

Immune responses to influenza (flu) antigens reflect memory of prior infections or vaccinations, which might influence immunity to new flu antigens. Memory of past antigens has been termed "original antigenic sin" or, more recently, "immune imprinting" and "seniority". We have researched a comparison between the immune response to live flu infections and inactivated flu vaccinations. A brief history of antibody generation theories is presented, culminating in new findings about the immune-network theory and suggesting that a network of clones exists between anti-idiotypic antibodies and T cell receptors. Findings regarding the 2009 pandemic flu strain and immune responses to it are presented, including memory B cells and conserved regions within the hemagglutinin protein. The importance of CD4+ memory T cells and cytotoxic CD8+ T cells responding to both infections and vaccinations are discussed and compared. Innate immune cells, like natural killer (NK) cells and macrophages, are discussed regarding their roles in adaptive immune responses. Antigen presentation via macroautophagy processes is described. New vaccines in development are mentioned along with the results of some clinical trials. The manuscript concludes with how repeated vaccinations are impacting the immune system and a sketch of what might be behind the imprinting phenomenon, including future research directions.

Transformative vaccination: A pentavalent shield against COVID-19 and influenza with betulin-based adjuvant for enhanced immunity

The development of an effective combined vaccine represents a crucial strategy for preventing outbreaks of infectious diseases and reducing the burden on healthcare resources. Developing a combined vaccine against both influenza and the coronavirus is a promising approach, but it is still in the early stages of development. This paper reports on a novel combined pentavalent candidate vaccine that has shown promising results in mice, with statistically significant differences in mean antibody titer against the coronavirus and the influenza antigens compared to placebo. We have shown that the coronavirus antigen is capable of inducing an immune response autonomously, regardless of the presence of the influenza antigens in a combined vaccine. On the other hand, the presence of the coronavirus antigen in a combined vaccine showed to enhance the immune response against some of the studied influenza antigens, suggesting that these antigens may act in synergy and elicit an enhanced immune response. The absence of dose-dependent difference in mean antibody titer within the same antigenic groups of vaccine preparations suggested that even small amounts of the coronavirus and the influenza antigens could induce an immune response just as good as high-dose vaccine preparations, which certainly has important safety and cost implications. The vaccine is soon to be ready for clinical trials and mass production.

Differential Immune Response Patterns Induced by Anionic and Cationic Lipid Adjuvants in Intranasal Anti-Influenza Immunization.

Currently, vaccine development against different respiratory diseases is at its peak. It is of utmost importance to find suitajble adjuvants that can increase the potency of the vaccine candidates. This study aimed to determine the systemic and splenic immune mechanisms in mice models induced by anionic and cationic lipid adjuvants in the presence of the vaccine-candidate influenza antigen hemagglutinin (HA). In the presence of the HA antigen, the cationic adjuvant (N3) increased conventional dendritic cell 1 (cDC1) abundance with enhanced MHCI and CD80-CD86 costimulatory marker expression, and significantly higher CD8T and Th17 populations with enhanced interferon-gamma (IFNγ) expression in CD8T and CD4T populations. Conversely, the anionic adjuvant (L3) increased the cDC2 population percentage with significantly higher MHCII and DEC205 expression, along with an increase in the CD4T and regulatory T cell populations. The L3-treated group also exhibited higher percentages of activated B and plasma cell populations with significantly higher antigen-specific IgG and IgA titer and virus neutralization potential. While the anionic adjuvant induced significantly higher humoral responses than the cationic adjuvant, the latter influenced a significantly higher Th1/Th17 response. For customized vaccine development, it is beneficial to have alternative adjuvants that can generate differential immune responses with the same vaccine candidate antigen. This study will aid the selection of adjuvants based on their charges to improve specific immune response arms in the future development of vaccine formulation.

MRNA vaccines encoding computationally optimized hemagglutinin elicit protective antibodies against future antigenically drifted H1N1 and H3N2 influenza viruses isolated between 2018-2020.

The implementation of mRNA vaccines against COVID-19 has successfully validated the safety and efficacy of the platform, while at the same time revealing the potential for their applications against other infectious diseases. Traditional seasonal influenza vaccines often induce strain specific antibody responses that offer limited protection against antigenically drifted viruses, leading to reduced vaccine efficacy. Modern advances in viral surveillance and sequencing have led to the development of in-silico methodologies for generating computationally optimized broadly reactive antigens (COBRAs) to improve seasonal influenza vaccines. In this study, immunologically naïve mice were intramuscularly vaccinated with mRNA encoding H1 and H3 COBRA hemagglutinins (HA) or wild-type (WT) influenza HAs encapsulated in lipid nanoparticles (LNPs). Mice vaccinated with H1 and H3 COBRA HA-encoding mRNA vaccines generated robust neutralizing serum antibody responses against more antigenically distinct contemporary and future drifted H1N1 and H3N2 influenza strains than those vaccinated with WT H1 and H3 HA-encoding mRNA vaccines. The H1 and H3 COBRA HA-encoding mRNA vaccines also prevented influenza illness, including severe disease in the mouse model against H1N1 and H3N2 viruses. This study highlights the potential benefits of combining universal influenza antigen design technology with modern vaccine delivery platforms and exhibits how these vaccines can be advantageous over traditional WT vaccine antigens at eliciting superior protective antibody responses against a broader number of influenza virus isolates.

Evaluation of CLINITEST® Rapid Covid-19 + Influenza antigen test in a cohort of symptomatic patients in an emergency department.

Rapid management of patients with respiratory tract infections in hospital emergency departments is one of the main objectives since the concurrent circulation of respiratory viruses following the SARS-CoV-2 pandemic. The use of new combined point-of-care antigen tests for detecting influenza A/B and SARS-CoV-2 represents an advantage in response time over the molecular tests. The objective was to evaluate the suitability of the CLINITEST® Rapid Covid-19 + Influenza Antigen test (Siemens Healthineers, Germany) (RCIA test) by measuring the sensitivity, specificity, Cohen's kappa, and cut-off values. Nasopharyngeal samples were collected from a randomised group of symptomatic patients of all ages at emergency department during January-February 2023. In parallel, these patients were screened for influenza A/B, and SARS-CoV-2 using RT-PCR. The Ct (cycle threshold) values were collected for positive [RT-PCR (+) /RCIA test (+)] and false negative [(RT-PCR (+) /RCIA test (-)] samples. A subanalysis was performed in the paediatric population (< 16 years-old). We included 545 patients (55.8% females) with a median age of 7 years-old (IQR: 1-66.5). The RCIA test showed a sensitivity of 59.7% [95%CI: 46.9-67.33] for influenza A, 65.6% [95%CI: 49.5-80.3] for influenza B, and 76.9% [95%CI: 45.8-84.8] for SARS-CoV-2. The specificity was between 90.7%-99.7% with a moderate/high level of agreement with RT-PCR (kappa score: 0.6-0.8) for the three respiratory viruses included in the RCIA test. The sensitivity of the RCIA test is insufficient for screening of patients, including patients with low Ct values (Ct > 20). Despite its good specificity and Cohen's kappa value, its use as a screening test is not comparable to RT-PCR systems in the ED environment with a high number of false negative results.

PREDAC-CNN: predicting antigenic clusters of seasonal influenza A viruses with convolutional neural network.

Vaccination stands as the most effective and economical strategy for prevention and control of influenza. The primary target of neutralizing antibodies is the surface antigen hemagglutinin (HA). However, ongoing mutations in the HA sequence result in antigenic drift. The success of a vaccine is contingent on its antigenic congruence with circulating strains. Thus, predicting antigenic variants and deducing antigenic clusters of influenza viruses are pivotal for recommendation of vaccine strains. The antigenicity of influenza A viruses is determined by the interplay of amino acids in the HA1 sequence. In this study, we exploit the ability of convolutional neural networks (CNNs) to extract spatial feature representations in the convolutional layers, which can discern interactions between amino acid sites. We introduce PREDAC-CNN, a model designed to track antigenic evolution of seasonal influenza A viruses. Accessible at http://predac-cnn.cloudna.cn, PREDAC-CNN formulates a spatially oriented representation of the HA1 sequence, optimized for the convolutional framework. It effectively probes interactions among amino acid sites in the HA1 sequence. Also, PREDAC-CNN focuses exclusively on physicochemical attributes crucial for the antigenicity of influenza viruses, thereby eliminating unnecessary amino acid embeddings. Together, PREDAC-CNN is adept at capturing interactions of amino acid sites within the HA1 sequence and examining the collective impact of point mutations on antigenic variation. Through 5-fold cross-validation and retrospective testing, PREDAC-CNN has shown superior performance in predicting antigenic variants compared to its counterparts. Additionally, PREDAC-CNN has been instrumental in identifying predominant antigenic clusters for A/H3N2 (1968-2023) and A/H1N1 (1977-2023) viruses, significantly aiding in vaccine strain recommendation.

Co-Delivery of a Novel Lipidated TLR7/8 Agonist and Hemagglutinin-Based Influenza Antigen Using Silica Nanoparticles Promotes Enhanced Immune Responses.

Co-delivery of antigens and adjuvants to the same antigen-presenting cells (APCs) can significantly improve the efficacy and safety profiles of vaccines. Here, we report amine-grafted silica nanoparticles (A-SNP) as a tunable vaccine co-delivery platform for TLR7/8 agonists along with the recombinant influenza antigen hemagglutinin H7 (H7) to APCs. A-SNP of two different sizes (50 and 200 nm) were prepared and coated with INI-4001 at different coating densities, followed by co-adsorption of H7. Both INI-4001 and H7 showed >90% adsorption to the tested A-SNP formulations. TNF-α and IFN-α cytokine release by human peripheral blood mononuclear cells as well as TNF-α, IL-6, and IL-12 release by mouse bone marrow-derived dendritic cells revealed that the potency of the INI-4001-adsorbed A-SNP (INI-4001/A-SNP) formulations was improved relative to aqueous formulation control. This improved potency was dependent on particle size and ligand coating density. In addition, slow-release profiles of INI-4001 were measured from INI-4001/A-SNP formulations in plasma with 30-50% INI-4001 released after 7 days. In vivo murine immunization studies demonstrated significantly improved H7-specific humoral and Th1/Th17-polarized T cell immune responses with no observed adverse reactions. Low-density 50 nm INI-4001/A-SNP elicited significantly higher IFN-γ and IL-17 induction over that of the H7 antigen-only group and INI-4001 aqueous formulation controls. In summary, this work introduces an effective and biocompatible SNP-based co-delivery platform that enhances the immunogenicity of TLR7/8 agonist-adjuvanted subunit influenza vaccines.

Preservation of functionality, immunophenotype, and recovery of HIV RNA from PBMCs cryopreserved for more than 20 years.

Many research laboratories have long-term repositories of cryopreserved peripheral blood mononuclear cells (PBMC), which are costly to maintain but are of uncertain utility for immunological studies after decades in storage. This study investigated preservation of cell surface phenotypes and in-vitro functional capacity of PBMC from viraemic HIV+ patients and healthy seronegative control subjects, after more than 20 years of cryopreservation. PBMC were assessed by 18-colour flow cytometry for major lymphocyte subsets within T, B, NK, and dendritic cells and monocytes. Markers of T-cell differentiation and activation were compared with original immunophenotyping performed in 1995/1996 on fresh blood at the time of collection. Functionality of PBMC was assessed by culture with influenza antigen or polyclonal T-cell activation, to measure upregulation of activation-induced CD25 and CD134 (OX40) on CD4 T cells and cytokine production at day 2, and proliferative CD25+ CD4 blasts at day 7. RNA was extracted from cultures containing proliferating CD4+ blast cells, and intracellular HIV RNA was measured using short amplicons for both the Double R and pol region pi code assays, whereas long 4-kbp amplicons were sequenced. All major lymphocyte and T-cell subpopulations were conserved after long-term cryostorage, except for decreased proportions of activated CD38+HLA-DR+ CD4 and CD8 T cells in PBMC from HIV+ patients. Otherwise, differences in T-cell subpopulations between recent and long-term cryopreserved PBMC primarily reflected donor age-associated or HIV infection-associated effects on phenotypes. Proportions of naïve, memory, and effector subsets of T cells from thawed PBMC correlated with results from the original flow cytometric analysis of respective fresh blood samples. Antigen-specific and polyclonal T-cell responses were readily detected in cryopreserved PBMC from HIV+ patients and healthy control donors. Intracellular HIV RNA quantitation by pi code assay correlated with original plasma viral RNA load results. Full-length intracellular and supernatant-derived amplicons were generated from 5/12 donors, and sequences were ≥80% wild-type, consistent with replication competence. This unique study provides strong rationale and validity for using well-maintained biorepositories to support immunovirological research even decades after collection.

Influenza A in children complicated by encephalitis - case study

Influenza is a seasonal disease that can cause annual outbreaks, especially during the cold periods of the year, in temperate areas. Symptomatology mainly involves the upper and lower respiratory tract, but varies greatly depending on the age and medical history of each person. In this paper we present a clinical case of influenza type A complicated with encephalitis in a female child aged 5 years and 6 months with a personal pathological history of neurological damage (Guillain-Barre syndrome). The diagnosis of influenza was established on the basis of symptoms (productive cough, rhinorrhea, marked physical asthenia, high fever) and confirmed by laboratory tests (rapid influenza antigen test and influenza RT PCR from nasopharyngeal secretions - positive). Neurological involvement was clinically supported by the occurrence of bradykinesia, bradypsy, broad-based gait, confirmed by neurological examination. The diagnosis of encephalitis was completed by analysis of cerebrospinal fluid (CSF) obtained by lumbar puncture in which influenza virus type A was identified and by electroencephalogram (EEG) showing altered tracing. Under antiviral (Oseltamivir), pathogenic (corticosteroid therapy), brain depleting (mannitol solution), non-specific human and symptomatic immunoglobulins treatments, the evolution was slowly favorable with remission of symptoms. The case presented argues that although influenza in immunocompetent children is generally a self-limiting and uncomplicated condition, it can evolve severely with the development of complications and after-effects and sometimes increased mortality especially in immunocompromised hosts.

Abstract 13309: Severe Cardiomyopathy as Harbinger of Multisystem Inflammatory Syndrome From Epstein Barr Infection

Introduction: Multisystem inflammatory syndrome in adults (MIS-A) is a rare condition characterized by multiple organ injury after a viral infection. Features include fever, elevated inflammatory markers, evidence of acute viral infection, and at least three of the following clinical criteria: peri/myocarditis or acute ventricular dysfunction, rash, encephalopathy, shock, and gastrointestinal symptoms. This is a case of nonischemic cardiomyopathy (NICMP) as a MIS-A manifestation after an Epstein-Barr viral (EBV) infection. Description of Case: A 38 year-old female, with a recent pneumonia, presented with two weeks of fever, dyspnea, hemoptysis, fatigue, and right leg swelling. Initial ECG showed sinus tachycardia. Laboratory testing showed leukocytosis 15.5k/uL, NT pro BNP 6470 pg/mL, C-reactive protein 234 mg/L, lactic acid 3.7 mmol/L, creatinine 1.5 mg/dL (baseline 0.7 mg/dL), AST 372 U/L, ALT 658 U/L. RSV, influenza, COVID-19, HIV, hepatitis B/C, and urine antigens were undetected. Imaging showed deep vein thrombosis in right leg veins and bilateral pulmonary emboli with infarcts. Heparin infusion was started. A transthoracic echocardiogram showed biventricular systolic failure with an ejection fraction of 20%. Coronary angiography showed no coronary artery disease. Cardiac MRI showed dilated NICMP with minimal late gadolinium enhancement. The nadir of her cardiac index was 1.2 L/min/m 2. She was started on nitroprusside infusion for early-stage cardiogenic shock. Extensive workup for thrombophilia, autoimmune, amyloidosis, infectious causes were all normal except for an elevated EBV early antigen IgG which indicated past infection within a few months, aligning with patient’s reported pneumonia symptoms before presentation. She clinically improved and was bridged to heart failure guideline directed medical therapy and apixaban on discharge. Discussion: Though MIS-A has been reportedly associated with COVID-19, EBV can cause MIS, with severe cardiomyopathy, nephropathy, hepatopathy, and pulmonary infarcts requiring intensive cardiac care, in a normal young adult.