Early Specification of CD8+ T Lymphocyte Fates during Adaptive Immunity Revealed by Single-Cell Gene-Expression Analyses T lymphocytes responding to microbial infection give rise to effector cells that mediate acute host defense and memory cells that provide long-lived immunity, but the fundamental question of when and how these cells arise remains unresolved. Scientists combined single-cell gene-expression analyses with ‘machine-learning’ approaches to trace the transcriptional ‘roadmap’ of individual CD8+ T lymphocytes throughout the course of an immune response in vivo. [Nat Immunol] Abstract | Press Release Blimp-1 Represses CD8 T Cell Expression of PD-1 Using a Feed-Forward Transcriptional Circuit during Acute Viral Infection Researchers showed that B lymphocyte-induced maturation protein 1 (Blimp-1)-deficient CD8 T cells fail to repress programmed cell death 1 (PD-1) during the early stages of CD8 T cell differentiation after acute infection with lymphocytic choriomeningitis virus strain Armstrong. [J Exp Med] Abstract Mapping the Innate Signaling Cascade Essential for Cytokine Storm during Influenza Virus Infection The authors showed that sphingosine-1-phosphate-1 receptor (S1P1R) agonist treatment suppresses global cytokine amplification. Importantly, S1P1R agonist treatment was able to blunt cytokine/chemokine production and innate immune cell recruitment in the lung independently of endosomal and cytosolic innate sensing pathways. [Proc Natl Acad Sci USA] Abstract | Press Release An Enzyme-Linked Immunospot Assay for the Detection of Human Respiratory Syncytial Virus F-Specific IFNγ-producing T Cells Respiratory syncytial virus (RSV) causes significant disease in elderly adults and the authors have previously reported that individuals 65 years of age and older have reduced RSV F-specific interferon gamma (IFNγ)-producing T cells compared to healthy younger adults. To measure RSV F-specific memory T cell responses in the elderly following infection or vaccination, they optimized and qualified an IFNγ enzyme-linked immunospot assay. [Clin Vaccine Immunol] Abstract HIV Developmental Pathway for Potent V1V2-Directed HIV-Neutralizing Antibodies Antibodies capable of neutralizing HIV-1 often target variable regions 1 and 2 (V1V2) of the HIV-1 envelope, but the mechanism of their elicitation has been unclear. Here researchers define the developmental pathway by which such antibodies are generated and acquire the requisite molecular characteristics for neutralization. [Nature] Abstract | Press Release A Compositional Look at the Human Gastrointestinal Microbiome and Immune Activation Parameters in HIV Infected Subjects Investigators hypothesized that the gastrointestinal (GI) mucosal microbiome is altered in HIV patients and this alteration correlates with immune activation in HIV. The composition of the lower GI tract mucosal and luminal bacterial microbiome was characterized using 16S rDNA pyrosequencing and was correlated to clinical parameters as well as immune activation and circulating bacterial products in HIV patients on ART. [PLoS Pathog] Abstract Impact of HIV on CD8+ T Cell CD57 Expression Is Distinct from That of CMV and Aging Researchers compared markers of CD8+ T cell differentiation (e.g., CD28, CD27, CCR7, CD45RA) and CD57 expression on CD28- CD8+ T cells in healthy HIV-uninfected adults with and without cytomegalovirus (CMV) infection and in both untreated and antiretroviral therapy-suppressed HIV-infected adults with asymptomatic CMV infection. [PLoS One] Abstract IL-10-Producing B Cells Are Induced Early in HIV-1 Infection and Suppress HIV-1-Specific T Cell Responses The authors examined the role of IL-10-producing B cells in HIV-1 infection. Compared to uninfected controls, IL-10-producing B cell frequencies were elevated in both blood and sigmoid colon during the early and chronic phase of untreated HIV-1 infection. [PLoS One] Abstract |