Siglec-5 and Siglec-14 Are Polymorphic Paired Receptors that Modulate Neutrophil and Amnion Signaling Responses to Group B Streptococcus Researchers showed that β-protein-expressing Group B Streptococcus binds to both sialic acid-binding immunoglobulin-like lectin 5 (Siglec-5) and Siglec-14 on neutrophils and that the latter engagement counteracts pathogen-induced host immune suppression by activating p38 mitogen-activated protein kinase and AKT signaling pathways. [J Exp Med] Abstract | Press Release Caspase-8 Mediates Caspase-1 Processing and Innate Immune Defense in Response to Bacterial Blockade of NF-κB and MAPK Signaling Data demonstrate that receptor-interacting serine/threonine kinase 1, Fas-associated death domain, and caspase-8 are required for YopJ-induced cell death and caspase-1 activation and suggest that caspase-8-mediated cell death overrides blockade of immune signaling by YopJ to promote anti-Yersinia immune defense. [Proc Natl Acad Sci USA] Abstract | Press Release NLRX1 Prevents Mitochondrial Induced Apoptosis and Enhances Macrophage Antiviral Immunity by Interacting with Influenza Virus PB1-F2 Protein Researchers found the host mitochondrial protein nucleotide-binding oligomerization domain-like receptor (NLR)X1 binds to viral protein PB1-F2, preventing influenza A virus-induced macrophage apoptosis and promoting both macrophage survival and Type I IFN signaling. [Proc Natl Acad Sci USA] Abstract Ubiquitination by SAG Regulates Macrophage Survival/Death and Immune Response during Infection Using in vitro and ex vivo approaches, researchers showed that macrophage survival is synchronized by SAG (sensitive to apoptosis gene), which is a key member of the ubiquitin-proteasome system. When challenged by pathogen-associated molecular patterns, they observed a reciprocal expression profile of pro- and antiapoptotic factors in macrophages. [Cell Death Differ] Full Article Tuberculin Skin Test Reversion following Isoniazid Preventive Therapy Reflects Diversity of Immune Response to Primary Mycobacterium tuberculosis Infection Researchers aimed to measure frequency of tuberculin skin test (TST) reversion following isoniazid preventive therapy, and variation in interferon-gamma responses to Mycobacterium tuberculosis (Mtb), in healthy Ugandan Tuberculosis healthy household contacts with primary Mtb infection evidenced by TST conversion. [PLoS One] Full Article HIV HIV and HCV Activate the Inflammasome in Monocytes and Macrophages via Endosomal Toll-Like Receptors without Induction of Type 1 Interferon Investigators demonstrated that HIV and HCV activate the inflammasome, but not Type I interferon production, in monocytes and macrophages in an infection-independent process that requires clathrin-mediated endocytosis and recognition of the virus by distinct endosomal Toll-like receptors. [PLoS Pathog] Full Article In Utero Exposure to Maternal HIV Infection Alters T-Cell Immune Responses to Vaccination in HIV-Uninfected Infants In sub-Saharan Africa, HIV-exposed uninfected (HEU) infants have higher morbidity and mortality than HIV-unexposed infants. To evaluate whether immune dysfunction contributes to this vulnerability of HEU infants, researchers conducted a longitudinal, observational cohort study to assess T-cell immune responses to infant vaccines (Mycobacterium bovis BCG and acellular pertussis) and staphylococcal enterotoxin B. [AIDS] Abstract Ineffectual Targeting of HIV-1 Nef by Cytotoxic T Lymphocytes in Acute Infection Results in No Functional Impairment or Viremia Reduction Scientists investigated whether CD8+ T lymphocyte targeting of Nef during acute infection contributes to immune control by disrupting its function. [J Virol] Abstract Cytomegalovirus Replication in Semen Is Associated with Higher Levels of Proviral HIV DNA and CD4+ T cell Activation during Antiretroviral Treatment To determine the connections between cytomegalovirus (CMV)-associated immune activation and the size of the viral reservoir, researchers evaluated the interactions between asymptomatic seminal CMV replication, levels of T cell activation and proliferation in blood, and the size and the transcriptional activity of the HIV DNA reservoir in blood from 53 HIV-infected men on long-term antiretroviral therapy with suppressed HIV RNA in blood plasma. [J Virol] Abstract Host Genetics and Immune Control of HIV-1 Infection: Fine Mapping for the Extended Human MHC Region in an African Cohort Multiple major histocompatibility complex (MHC) loci encoding human leukocyte antigens have allelic variants unequivocally associated with differential immune control of HIV-1 infection. Researchers tested the utility of a custom fine-mapping platform (the ImmunoChip) for 172 HIV-1 seroconverters and 449 seroprevalent individuals from Lusaka, Zambia, with a focus on more than 6400 informative extended MHC single nucleotide polymorphisms. [Genes Immun] Abstract |