Biology subjects

Reeves, R. K.

Publications and source records attributed to Reeves, R. K..

3 recordsLinked to original sources

bioRxiv2021

Systemic and mucosal mobilization of granulocyte subsets during lentivirus infection

Granulocytes mediate broad immunoprotection through phagocytosis, extracellular traps, release of cytotoxic granules, antibody effector functions and recruitment of other immune cells against pathogens. However, descriptions of granulocytes in HIV infection and mucosal tissues are limited. Our goal was to characterize granulocyte subsets in systemic, mucosal and lymphoid tissues during lentivirus infection using the rhesus macaque (RM) model. Mononuclear cells from jejunum, colon, cervix, vagina, lymph nodes, spleen, liver, and whole blood from naive, and chronically SHIVsf162p3-infected RM were analyzed by microscopy and polychromatic flow cytometry. Granulocytes were identified using phenotypes designed specifically for RM: eosinophils - CD45+CD66+CD49d+; neutrophils - CD45+CD66+CD14+; and basophils - CD45+CD123+FcR{varepsilon}+. Nuclear visualization with DAPI staining and surface marker images by ImageStream (cytometry/microscopy) further confirmed granulocytic phenotypes. Flow cytometric data showed that all RM granulocytes expressed CD32 (FcR{gamma}II) but did not express CD16 (FcR{gamma}III). Additionally, constitutive expression of CD64 (FcR{gamma}I) on neutrophils and FcR{varepsilon} on basophils, indicates the differential expression of Fc receptors on granulocyte subsets. Granulocytic subsets in naive whole blood ranged 25.4-81.5% neutrophils, 0.59-13.3% eosinophils and 0.059-1.8% basophils. Interestingly, elevated frequencies of circulating neutrophils, colorectal neutrophils, and colorectal eosinophils were all observed in chronic lentivirus disease. Conversely, circulating basophils, jejunal eosinophils, vaginal neutrophils, and vaginal eosinophils of SHIVsf162p3-infected RM declined in frequency. Overall, our data suggest modulation of granulocytes in chronic lentivirus infection, most notably in the gastrointestinal mucosae where significant inflammation and disruption occurs in lentivirus-induced disease. Furthermore, granulocytes may migrate to inflamed tissues during infection and could serve as targets of immunotherapeutic intervention.

immunology↗

bioRxiv2020

Probiotic Supplementation Reduces Inflammatory Profiles But Does Not Prevent Oral Immune Perturbations During SIV Infection

HIV/SIV infections lead to massive loss of mucosal CD4+ T cells and breakdown of the epithelial mucosa resulting in severe microbial dysbiosis and chronic immune activation that ultimately drive disease progression. Moreover, disruption of one of the most understudied mucosal environments, the oral cavity, during HIV-induced immunosuppression results in significant microbial and neoplastic co-morbidities and contributes to and predicts distal disease complications. In this study we evaluated the effects of oral probiotic supplementation (Pbx), which can stimulate and augment inflammatory or anti-inflammatory pathways, on early SIV infection of rhesus macaques. Our study revealed that similar to the GI mucosae, oral CD4+ T cells were rapidly depleted, and as one of the first comprehensive analyses of the oral microflora in SIV infection, we also observed significant modulation among two genera, Porphyromonas and Actinobacillus, early after infection. Interestingly, although Pbx therapy did not substantially protect against oral dysbiosis or ameliorate cell loss, it did dampen inflammation and T cell activation. Collectively, these data provide one of the most comprehensive evaluations of SIV-induced changes in oral microbiome and CD4+ T cell populations, and also suggest that oral Pbx could be a simple therapy to improve anti-inflammatory states in addition to more traditional antivirals.

immunology↗

bioRxiv2020

Human antigen-specific memory natural killer cell responses develop against HIV-1 and influenza virus and are dependent on MHC-E restriction

For over a decade, multiple studies have disputed the notion of natural killer (NK) cells as purely innate lymphocytes by demonstrating that they are capable of putative antigen-specific immunological memory against multiple infectious agents including two critical global health priorities - HIV and influenza. However, the mechanisms underlying antigen specificity remain unknown. Herein, we demonstrate that antigen-specific human NK cell memory develops upon exposure to both HIV and influenza, unified by a conserved and epitope-specific targetable mechanism firmly dependent on the activating CD94/NKG2C receptor and its ligand HLA-E, and confirm these findings by three rigorous and novel assays. We validated the permanent acquisition of antigen-specificity by individual memory NK cells by single-cell cloning. We identified biomarkers of antigen-specific NK cell memory through RNA-Seq transcriptomic fingerprints and complex immunophenotyping by 30-parameter flow cytometry showing elevated expression of KLRG1, 4{beta}7 and NKG2C. Finally, we show individual HLA-E-restricted peptides that may constitute the dominant response in HIV-1- and influenza-infected persons in vivo. Our findings clarify the mechanisms behind formation of antigen-specific memory NK cells, and suggest they could be targeted for future vaccines, cure strategies, or other therapeutic interventions.

immunology↗