SEARCH · Search bioRxiv

Results for “Immunology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources

bioRxiv2022

Hybrid immunity shifts the Fc-effector quality of SARS-CoV-2 mRNA vaccine-induced immunity

Despite the robust immunogenicity of SARS-CoV-2 mRNA vaccines, emerging data reveal enhanced neutralizing antibody and T cell cross-reactivity among individuals that previously experienced COVID-19, pointing to a hybrid immune advantage with infection-associated immune priming. Beyond neutralizing antibodies and T cell immunity, mounting data point to a potential role for additional antibody effector functions, including opsinophagocytic activity, in the resolution of symptomatic COVID-19. Whether hybrid immunity modifies the Fc-effector profile of the mRNA vaccine-induced immune response remains incompletely understood. Thus, here we profiled the SARS-CoV-2 specific humoral immune response in a group of individuals with and without prior COVID-19. As expected, hybrid Spike-specific antibody titers were enhanced following the primary dose of the mRNA vaccine, but were similar to those achieved by naive vaccinees after the second mRNA vaccine dose. Conversely, Spike-specific vaccine-induced Fc-receptor binding antibody levels were higher after the primary immunization in individuals with prior COVID-19, and remained higher following the second dose compared to naive individuals, suggestive of a selective improvement in the quality, rather than the quantity, of the hybrid humoral immune response. Thus, while the magnitude of antibody titers alone may suggest that any two antigen exposures - either hybrid immunity or two doses of vaccine alone - represent a comparable prime/boost immunologic education, we find that hybrid immunity offers a qualitatively improved antibody response able to better leverage Fc effector functions against conserved regions of the virus.

immunology↗

bioRxiv2022

Oxysterols drive inflammation via GPR183 during influenza virus and SARS-CoV-2 infection

RationaleSevere viral respiratory infections are often characterized by extensive myeloid cell infiltration and activation and persistent lung tissue injury. However, the immunological mechanisms driving excessive inflammation in the lung remain elusive. ObjectivesTo identify the mechanisms that drive immune cell recruitment in the lung during viral respiratory infections and identify novel drug targets to reduce inflammation and disease severity. MethodsPreclinical murine models of influenza virus and SARS-CoV-2 infection. ResultsOxidized cholesterols and the oxysterol-sensing receptor GPR183 were identified as drivers of monocyte-macrophage infiltration to the lung during influenza virus (IAV) and SARS-CoV-2 infections. Both IAV and SARS-CoV-2 infections upregulated the enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) in the lung, resulting in local production of the oxidized cholesterols 25-hydroxycholesterol and 7,25-dihydroxycholesterol (7,25-OHC). Loss-of-function mutation of GPR183, or treatment with a GPR183 antagonist, reduced macrophage infiltration and inflammatory cytokine production in the lungs of IAV- or SARS-CoV-2-infected mice. The GPR183 antagonist also significantly attenuated the severity of SARS-CoV-2 infection by reducing weight loss and viral loads. ConclusionThis study demonstrates that oxysterols drive inflammation in the lung and provides the first preclinical evidence for therapeutic benefit of targeting GPR183 during severe viral respiratory infections. Author SummaryViral infections trigger oxysterol production in the lung, attracting macrophages via GPR183. Blocking GPR183 reduced inflammation and disease severity in SARS-CoV-2 infection, making GPR183 a putative target for therapeutic intervention.

immunology↗

bioRxiv2022

Segmental flexibility of bispecific T-cell engagers regulates the dynamics of immune synapse formation

Bispecific T-cell engagers (TcEs) link T cell receptors to tumor-associated antigens on cancer cells, forming cytotoxic immunological synapses (IS). Close membrane-to-membrane contact ([≤]13 nm) has been proposed as a key mechanism of TcE function. To investigate this and identify potential additional mechanisms, we compared four immunoglobulin G1-based (IgG1) TcE Formats (A-D) targeting CD3{varepsilon} and Her2, designed to create varying intermembrane distances (A B=C>D. In a minimal system for IS formation on SLBs, TcE performance followed the trend A=B=C>D. Addition of close-contact requiring CD58 co-stimulation revealed phospholipase C-{gamma} activation matching cytotoxicity with A>B=C>D. Our findings suggest that, when adhesion is equivalent, TcE potency is determined by two parameters: contact distance and flexibility. Both the close/far-contact formation axis and the low/high flexibility axis significantly impact TcE potency, explaining the similar potency of Format B (close-contact/high flexibility) and C (far-contact/low flexibility). Significance statementBispecific T-cell engagers (TcEs) are immunotherapeutic drugs that trigger the destruction of cancer cells by linking T cells to cancer cell through specific surface molecules (antigens). We designed a series of TcEs with varying distances between their binding sites and flexibilities of the TcE-antigen complexes. By combining structural and functional analyses, we confirmed close-contact formation between T cells and cancer cells as a critical determinant, mediated by co-activating receptors. Furthermore, we also identified molecular flexibility of the TcE-antigen complex as a further critical parameter for TcE potency. These findings provide novel insights into TcE function and highlight the importance of both parameters for future research and the design of improved immunotherapies.

immunology↗

bioRxiv2022

Bystander memory-phenotype conventional CD4+ T cells exacerbating autoimmune neuroinflammation

Memory-phenotype (MP) CD4+ T cells are a substantial population of conventional T cells that exist in steady-state mice, and their immunologic functions in autoimmune disease have not yet been studied. In this work, we unveil a unique phenotype of MP CD4+ T cells by analyzing single-cell transcriptomics and T cell receptor (TCR) repertoires. We found that steady-state MP CD4+ T cells exist regardless of germ and food-antigen which are composed of heterogenous effector subpopulations. Distinct subpopulations of MP CD4+ T cells are specifically activated by IL-1 family cytokines and STAT activators, revealing that the cells have TCR-independent effector functions. Especially, CCR6high MP CD4+ T cells are major responders to IL-1{beta} and IL-23 without MOG35-55 antigen reactivity, which gives them pathogenic-Th17 characteristics and allows them to contribute to autoimmune encephalomyelitis. We identified Bhlhe40 in CCR6high MP CD4+ T cells drives the expression of GM-CSF, contributing to CNS pathology in experimental autoimmune encephalomyelitis. Collectively, our findings reveal heterogeneity of MP CD4+ T cells that can contribute to autoimmune neuroinflammation in bystander manner synergistically with antigen-specific T cells.

immunology↗

bioRxiv2022

Anamnestic Humoral Correlates of Immunity Across SARS-CoV-2 Variants of Concern

While immune correlates against SARS-CoV-2 are typically defined at peak immunogenicity following vaccination, immunologic responses that expand selectively during the anamnestic response following infection can provide mechanistic and detailed insights into the immune mechanisms of protection. Moreover, whether anamnestic correlates are conserved across VoCs, including the Delta and more distant Omicron variant of concern (VoC), remains unclear. To define the anamnestic correlates of immunity, across VOCs, we deeply profiled the humoral immune response in individuals recently infected with either the Delta or Omicron VoC. While limited acute N-terminal domain and RBD-specific immune expansion was observed following breakthrough, a significant immunodominant expansion of opsinophagocytic Spike-specific antibody responses focused largely on the conserved S2-domain of SARS-CoV-2 was observed 1 week after breakthrough infection. This S2-specific functional humoral response continued to evolve over 2-3 weeks following both Delta and Omicron breakthrough infection, targeting multiple VoCs and common coronaviruses. These responses were focused largely on the fusion peptide 2 and heptad repeat 1, both associated with enhanced rates of viral clearance. Taken together, our results point to a critical role of highly conserved, functional S2-specific responses in the control of SARS-CoV-2 infection, across VOCs, and thus humoral response linked to virus attenuation can guide next-generation generation vaccine boosting approaches to confer broad protection against future SARS-CoV-2 VoCs.

immunology↗

bioRxiv2022

Enhancement of mitochondrial function fosters B cell immune memory

Differentiation of T and B cells to effector and memory cell fates are associated with extensive metabolic changes which are accompanied by altered mitochondrial dynamics. However, whether alterations in mitochondrial structure and function plays an active role in regulating effector versus memory cell fate decisions during immune responses remains unclear. Our studies here characterize changes in mitochondrial dynamics in activated B cells and show that increased mitochondrial mass and activity is a distinct feature of memory B cell lineage commitment in vivo. Using a directed screen of mitochondrial modulators, we identify mitochondrial fission inhibitor, Mdivi-1 as an agent that could enhance mitochondrial mass and function leading to augmented memory B cell differentiation. The enhanced memory B cell responses mediated by Mdivi-1, translated to more robust recall responses upon secondary antigen exposures. Moreover, Mdivi-1 when used in combination with subunit (SARS-CoV2) and inactivated (H1N1 influenza) vaccines led to remarkably improved vaccine efficacies and protection from lethal viral (H1N1) challenge. Single-cell transcriptomics revealed enhanced commitment to memory lineage differentiation in B cells following Mdivi-1 treatment. We propose that mitochondrial modulators such as Mdivi-1 are a novel class of "immune enhancers" that specifically reinforces immunological memory and could be broadly applied to improve the fidelity of immune responses and vaccine efficacies.

immunology↗

bioRxiv2022

The guanine nucleotide exchange factor Rin-like acts as a gatekeeper for T follicular helper cell differentiation via regulating CD28 signaling

T follicular helper (Tfh) cells are essential for the development of germinal center B cells and high-affinity antibody producing B-cells in human and mice. Here, we identify the guanine nucleotide exchange factor (GEF) Rin-like (Rinl) as a negative regulator of Tfh generation. Loss of Rinl leads to an increase of Tfh in aging, upon in vivo immunization and acute LCMV Armstrong infection in mice, and in human CD4+ T cell in vitro cultures. Further, adoptive transfer experiments using WT and Rinl-KO naive CD4+ T cells unraveled T cell-intrinsic functions of Rinl. Mechanistically, Rinl regulates CD28 internalization and signaling, thereby shaping CD4+ T cell activation and differentiation. Thus, our results identify the GEF Rinl as a negative regulator of global Tfh differentiation in an immunological context and species-independent manner, and furthermore connect Rinl with CD28 internalization and signaling pathways in CD4+ T cells, demonstrating for the first-time the importance of endocytic processes for Tfh differentiation. HighlightsO_LIRinl-KO CD4+ T cells show increased Tfh differentiation in a context independent manner C_LIO_LIThe regulation of Tfh differentiation is T cell-intrinsic C_LIO_LIRinl controls CD28 endocytosis and shapes Tfh-specific CD28 signal transduction C_LIO_LIHuman Tfh differentiation is regulated by Rinl C_LI

immunology↗

bioRxiv2022

An Atlas of Cells in the Human Tonsil

Palatine tonsils are secondary lymphoid organs representing the first line of immunological defense against inhaled or ingested pathogens. Here, we present a comprehensive census of cell types forming the human tonsil by applying single-cell transcriptome, epigenome, proteome and adaptive immune repertoire sequencing as well as spatial transcriptomics, resulting in an atlas of >357,000 cells. We provide a glossary of 121 annotated cell types and states, and disentangle gene regulatory mechanisms that drive cells through specialized lineage trajectories. Exemplarily, we stratify multiple tonsil-resident myeloid slancyte subtypes, establish a distant BCL6 superenhancer as locally active in both follicle-associated T and B cells, and describe SIX5 as a potentially novel transcriptional regulator of plasma cell maturation. Further, our atlas is a reference map to understand alterations observed in disease. Here, we discover immune-phenotype plasticity in tumoral cells and microenvironment shifts of mantle cell lymphomas (MCL). To facilitate such reference-based analysis, we develop HCATonsilData and SLOcatoR, a computational framework that provides programmatic and modular access to our dataset; and allows the straightforward annotation of future single-cell profiles from secondary lymphoid organs.

immunology↗

bioRxiv2022

Weight cycling induces innate immune memory in adipose tissue macrophages

Weight loss improves obesity-associated diabetes risk. However, most individuals regain weight, which worsens the risk of developing diabetes and cardiovascular disease. We previously reported that male mice retain obesity-associated immunological changes even after weight loss, suggesting that immune cells may remember the state of obesity. Therefore, we hypothesized that cycles of weight gain and loss, otherwise known as weight cycling, can induce innate memory in adipose macrophages. We first treated bone marrow derived macrophages in a culture model of innate immune memory. Priming the cells with palmitic acid or adipose tissue conditioned media increased maximal glycolysis, oxidative phosphorylation, and increased LPS-induced TNF and IL-6 production. While weight loss improved glucose tolerance, adipose macrophages retained elevated LPS-induced cytokine production. In a model of weight cycling, adipose macrophages had elevated metabolism and secreted higher levels of basal TNF. Together, these data suggest that obesity and subsequent weight loss can prime adipose macrophages for enhanced inflammation upon weight regain. This innate immune memory response may contribute to worsened glucose tolerance following weight cycling.

immunology↗

bioRxiv2022

Fc effector activity and neutralization against SARS-CoV-2 BA.4 is compromised in convalescent sera, regardless of the infecting variant

The SARS-CoV-2 Omicron BA.1 variant, which exhibits high level neutralization resistance, has since evolved into several sub-lineages including BA.4 and BA.5, which have dominated the fifth wave of infection in South Africa. Here we assessed the sensitivity of BA.4 to neutralization and antibody dependent cellular cytotoxicity (ADCC) in convalescent donors infected with four previous variants of SARS-CoV-2, as well as in post-vaccination breakthrough infections (BTIs) caused by Delta or BA.1. We confirm that BA.4 shows high level resistance to neutralization, regardless of the infecting variant. However, breakthrough infections, which trigger potent neutralization, retained activity against BA.4, albeit at reduced titers. Fold reduction of neutralization in BTIs was lower than that seen in unvaccinated convalescent donors, suggesting maturation of neutralizing responses to become more resilient against VOCs in hybrid immunity. BA.4 sensitivity to ADCC was reduced but remained detectable in both convalescent donors and in BTIs. Overall, the high neutralization resistance of BA.4, even to antibodies from BA.1 infections, provides an immunological mechanism for the rapid spread of BA.4 immediately after a BA.1-dominated wave. Furthermore, although ADCC activity against BA.4 was reduced, residual activity may nonetheless contribute to the protection from disease.

immunology↗

bioRxiv2022

Single-cell profiling identifies ACE+ granuloma macrophages as a non-permissive niche for intracellular bacteria during persistent Salmonella infection

Macrophages mediate key antimicrobial responses against intracellular bacterial pathogens, such as Salmonella enterica. Yet, they can also act as a permissive niche for these pathogens to persist in infected tissues within granulomas, which are immunological structures comprised of macrophages and other immune cells. We apply single-cell transcriptomics to investigate macrophage functional diversity during persistent Salmonella enterica serovar Typhimurium (STm) infection in mice. We identify determinants of macrophage heterogeneity in infected spleens and describe populations of distinct phenotypes, functional programming, and spatial localization. Using a STm mutant with impaired ability to polarize macrophage phenotypes, we find that angiotensin converting enzyme (ACE) defines a granuloma macrophage population that is non-permissive for intracellular bacteria and their abundance anticorrelates with tissue bacterial burden. Disruption of pathogen control by neutralizing TNF preferentially depletes ACE+ macrophages in infected tissues. Thus ACE+ macrophages have differential capacity to serve as cellular niche for intracellular bacteria to establish persistent infection. TeaserThis study shows that ACE+ granuloma macrophages have restricted capacity to act as a cellular niche that enables intracellular bacterial persistence.

immunology↗

bioRxiv2022

Primary Omicron infection elicits weak antibody response but robust cellularimmunity in children

Omicron variants of SARS-CoV-2 are globally dominant and infection rates are very high in children. We determined immune responses following Omicron BA.1/2 infection in children aged 6-14 years and related this to prior and subsequent SARS-CoV-2 infection or vaccination. Primary Omicron infection elicited a weak antibody response with poor functional neutralizing antibodies. Subsequent Omicron reinfection or COVID-19 vaccination elicited increased antibody titres with broad neutralisation of Omicron subvariants. Prior pre-Omicron SARS-CoV-2 virus infection or vaccination primed for robust antibody responses following Omicron infection but these remained primarily focussed against ancestral variants. Primary Omicron infection thus elicits a weak antibody response in children which is boosted after reinfection or vaccination. Cellular responses were robust and broadly equivalent in all groups, providing protection against severe disease irrespective of SARS-CoV-2 variant. Immunological imprinting is likely to act as an important determinant of long-term humoral immunity, the future clinical importance of which is unknown.

immunology↗

bioRxiv2022

Enhanced viral infectivity and reduced interferon production are associated with high pathogenicity for influenza viruses

Epidemiological and clinical evidence indicates that humans infected with the 1918 pandemic influenza virus and highly pathogenic avian H5N1 influenza viruses often displayed severe lung pathology. High viral load and extensive infiltration of macrophages are the hallmarks of highly pathogenic (HP) influenza viral infections. However, it remains unclear what biological mechanisms primarily determine the observed difference in the kinetics of viral load and macrophages between HP and low pathogenic (LP) viral infections, and how the mechanistic differences are associated with viral pathogenicity. In this study, we develop a mathematical model of viral dynamics that includes the dynamics of different macrophage populations and interferon. We fit the model to in vivo kinetic data of viral load and macrophage level from BALB/c mice infected with an HP or LP strain of H1N1/H5N1 virus using Bayesian inference. Our primary finding is that HP viruses has a higher viral infection rate, a lower interferon production rate and a lower macrophage recruitment rate compared to LP viruses, which are strongly associated with more severe tissue damage (quantified by a higher percentage of epithelial cell loss). We also quantify the relative contribution of macrophages to viral clearance and find that macrophages do not play a dominant role in direct clearance of free virus although their role in mediating immune responses such as interferon production is crucial. Our work provides new insight into the mechanisms that convey the observed difference in viral and macrophage kinetics between HP and LP infections and establishes an improved model fitting framework to enhance the analysis of new data on viral pathogenicity. Author SummaryInfections with highly pathogenic (HP) influenza virus (e.g., the 1918 pandemic virus) often lead to serious morbidity and mortality. HP influenza virus infection is characterised by rapid viral growth rate, high viral load and excessive infiltration of macrophages to the lungs. Despite extensive study, we do not yet fully understand what biological processes leading to the observed viral and macrophage dynamics and therefore viral pathogenicity. Experimental studies have previously suggested that bot viral factors (e.g., viral proteins) and host factors (e.g., the host immune response) play a role to enhance viral pathogenicity. Here, we utilise in vivo kinetic data of viral load and macrophages and fit a viral dynamic model the data. Our model allow us to explore the biological mechanisms that contribute to the difference viral and macrophage dynamics between HP and LP infections. This study improves our understanding of the role of interferon on distinguishing immunodynamics between HP and LP infections. Our findings may contribute to the development of next-generation treatment which rely upon an understanding of the host different immunological response to HP influenza viruses.

immunology↗

bioRxiv2022

Memory B cells and memory T cells induced by SARS-CoV-2 booster vaccination or infection show different dynamics and efficacy to the Omicron variant.

Although BNT162b2 vaccination was shown to prevent infection and reduce COVID-19 severity, and the persistence of immunological memory generated by the vaccination has not been well elucidated. We evaluated memory B and T cell responses to the SARS-CoV-2 spike protein before and after the third BNT162b2 booster. Although the antibody titer against the spike receptor-binding domain (RBD) decreased significantly 8 months after the second vaccination, the number of memory B cells continued to increase, while the number of memory T cells decreased slowly. Memory B and T cells from unvaccinated infected patients showed similar kinetics. After the third vaccination, the antibody titer increased to the level of the second vaccination, and memory B cells increased at significantly higher levels before the booster, while memory T cells recovered close to the second vaccination levels. In memory T cells, the frequency of CXCR5+CXCR3+CCR6- cTfh1 was positively correlated with RBD-specific antibody-secreting B cells. Furthermore, T cell-dependent antibody production from reactivated memory B cells in vitro was correlated to the Tfh-like cytokine levels. For the response to variant RBDs, although 60%-80% of memory B cells could bind to the Omicron RBD, their binding affinity was low, while memory T cells show an equal response to the Omicron spike. Thus, the persistent presence of memory B and T cells will quickly upregulate antibody production and T cell responses after Omicron strain infection, which prevents severe illness and death due to COVID-19.

immunology↗

bioRxiv2022

Long-lived central memory γδ T cells confer protection against murine cytomegalovirus reinfection

The involvement of {gamma}{delta} TCR-bearing lymphocytes in immunological memory has gained increasing interest due to their functional duality between adaptive and innate immunity. {gamma}{delta} T effector memory (TEM) and central memory (TCM) subsets have been identified, but their respective roles in memory responses are poorly understood. In the present study, we used subsequent mouse cytomegalovirus (MCMV) infections of {beta} T cell deficient mice in order to analyze the memory potential of {gamma}{delta} T cells. As for CMV-specific {beta} T cells, MCMV induced the accumulation of cytolytic, KLRG1+CX3CR1+ {gamma}{delta} TEM that principally localized in infected organ vasculature. Typifying T cell memory, {gamma}{delta} T cell expansion/proliferation in organs and blood was higher and more efficient after secondary viral challenge than after primary infection. Viral control upon MCMV reinfection involved the T-cell receptor, and was associated with a preferential amplification of private and unfocused TCR {delta} chain repertoire as evidenced by next generation sequencing. The {gamma}{delta} T cell secondary response to MCMV was composed by a combination of clonotypes expanded post-primary infection and, more unexpectedly, of novel expanded clonotypes. Finally, Long-term-primed {gamma}{delta} TCM cells, but not {gamma}{delta} TEM cells, protected T cell-deficient hosts against MCMV-induced death upon adoptive transfer, probably through their ability to survive and to generate TEM in the recipient host. Overall, our study uncovered memory properties of long-lived TCM {gamma}{delta} T cells that confer protection in a chronic infection, highlighting the interest of this T cell subset in vaccination approaches. AUTHOR SUMMARYCytomegalovirus (CMV) is a widespread, latent virus that can cause severe organ disease in immune-compromised patients. Anti-CMV memory immune responses are essential to control viral reactivation and/or reinfection events that commonly take place in solid organ transplantation. The role of {gamma}{delta} T-cell receptor bearing lymphocytes could be crucial in this context where immunosuppressive/ablative treatments cause suboptimal and/or delayed {beta} T cell responses. Here we asked whether {gamma}{delta} T cells could compensate for the absence of {beta} T cells in the long-term control of mouse CMV infection. Three months post-primary viral challenge in {beta}-T cell deficient mice, {gamma}{delta} T cells displayed similar features as cytolytic, CMV-specific {beta} CD8 T cells. We showed that previous priming with CMV endowed {gamma}{delta} T cells with an enhanced antiviral potential and that long-term maintenance of {gamma}{delta}-mediated antiviral protection was dependent on {gamma}{delta} central memory T cells (TCM). The {gamma}{delta} T cell response to a secondary CMV challenge was dependent on {gamma}{delta} TCR-signaling and generated a private TCR {delta} repertoire as observed in human. Our results sustain the adaptive-like properties of these unconventional T cells and reveal the interest of targeting {gamma}{delta} TCM subset in novel antiviral vaccination approaches.

immunology↗

bioRxiv2022

Counting Is Almost All You Need

The immune memory repertoire encodes the history of present and past infections and immunological attributes of the individual. As such, multiple methods were proposed to use T-cell receptor (TCR) repertoires to detect disease history. We here show that the counting method outperforms all existing algorithms. We then show that the counting can be further improved using a novel attention model to weight the different TCRs. The attention model is based on the projection of TCRs using a Variational AutoEncoder (VAE). Both counting and attention algorithms predict better than any current algorithm whether the host had CMV and its HLA alleles. As an intermediate solution between the complex attention model and the very simple counting model, we propose a new Graph Convolutional Network approach that obtains the accuracy of the attention model and the simplicity of the counting model. The code for the models used in the paper are provided in: https://github.com/louzounlab/CountingIsAlmostAllYouNeed

immunology↗

bioRxiv2022

Dendritic cell-Natural Killer cell Crosstalk Modulates T cell activation in Response to Influenza A Viral Infection

Influenza viruses lead to substantial morbidity and mortality including ~3-5 million cases of severe illness and ~290,000-650,000 deaths annually. One of the major hurdles regarding influenza vaccine efficacy is generating a durable, robust cellular immune response. Appropriate stimulation of the innate immune system is key to generating cellular immunity. Crosstalk between innate dendritic cells (DC) and natural killer (NK) cells plays a key role in activating virus-specific T cells, yet the mechanisms used by influenza A viruses (IAV) to govern this process remain incompletely understood. Here, we used an ex vivo autologous human primary immune cell culture system to evaluate the impact of genetically distinct IAV strains on DC-NK cell crosstalk and subsequent T cell activation. We report that the addition of NK cells to cultures containing both DCs and naive T cells led to an increase in the frequency of CD69+ and CD25+ T cells and elevated levels of IFN-{gamma}, TNF, and IL-10. However, upon IAV infection of DCs, the addition of NK cells to cultures no longer increased the frequency of CD25+ T cells nor elevated IFN-{gamma}, TNF, and IL-10 cytokine levels. Investigation of the impact of IAV infection on DC-NK crosstalk revealed that exposure of DCs to influenza virus in co-culture led to an increased frequency of HLA-DR+ and a decreased frequency of CD83+ and CD86+ cells-molecules involved in stimulating T cell activation. An expansion of an HLA-DR+ NK cell subset was observed following culture with influenza-infected DCs in a contact-dependent and cytokine independent-manner. Overall, our results indicate a role for DC-NK cell crosstalk in T cell priming in the context of influenza infection, informing the immunological mechanisms that could be manipulated for the next generation influenza vaccine or immunotherapeutic.

immunology↗

bioRxiv2022

The Interactions of Potassium Hydroxide in the Vicinity of Connective Disulfide Bonds of the Fab Regions of Some Human Immunoglubulins: Preliminary Computational Implications for Affinity on Cys-Cys Disulfide Bridges

The average human lifespan continues to increase with the increase in data flow and the advancement of related technological developments. However, this development brings with it many diseases, including immunological problems. Immunoglobulin varieties found in different organisms in the last 3-4 decades continue to be hope for many diseases. Interest has focused on the lesser weight but more mobile immunoglobulins found in camelids. Later, different types of these antibodies were tried to be made with biotechnological engineering and their effectiveness continues to be investigated. Disulfide bridges located on the immunoglobulin are one of the key points for the structure and function of the immunoglobulin. The interest of potassium hydroxide in disulfide bridges may enable us to damage or break these bonds. For this purpose, in this study, the relationship between disulfide bridges between light and heavy chains and potassium hydroxide was investigated. It was observed that the affinity of potassium hydroxide to disulfide bridges occurred exergonically. In the light of this information, it can be thought that lighter, more functional immunoglobulin fragments and nanobodies can be formed with potassium hydroxide compared to conventional immunoglobulin.

immunology↗