Comparison of CyTOF assays across sites: Results of a six-center pilot study.

For more than five years, high-dimensional mass cytometry has been employed to study immunology. However, these studies have typically been performed in one laboratory on one or few instruments. We present the results of a six-center study using healthy control human peripheral blood mononuclear cells (PBMCs) and commercially available reagents to test the intra-site and inter-site variation of mass cytometers and operators.

Controlled Human Malaria Infection Leads to Long-Lasting Changes in Innate and Innate-like Lymphocyte Populations.

Animal model studies highlight the role of innate-like lymphocyte populations in the early inflammatory response and subsequent parasite control following infection. IFN-γ production by these lymphocytes likely plays a key role in the early control of the parasite and disease severity. Analyzing human innate-like T cell and NK cell responses following infection with has been challenging because the early stages of infection are clinically silent.

Distinct activation thresholds of human conventional and innate-like memory T cells.

Conventional memory CD8 T cells and mucosal-associated invariant T cells (MAIT cells) are found in blood, liver, and mucosal tissues and have similar effector potential following activation, specifically expression of IFN-γ and granzyme B. To better understand each subset's unique contributions to immunity and pathology, we interrogated inflammation- and TCR-driven activation requirements using human memory CD8 T and MAIT cells isolated from blood and mucosal tissue biopsies in ex vivo functional assays and single cell gene expression experiments. We found that MAIT cells had a robust IFN-γ and granzyme B response to inflammatory signals but limited responsiveness when stimulated directly via their TCR.

Dynamics of viral evolution and CTL responses in HIV-1 infection.

Improved understanding of the dynamics of host immune responses and viral evolution is critical for effective HIV-1 vaccine design. We comprehensively analyzed Cytotoxic T-lymphocyte (CTL)-viral epitope dynamics in an antiretroviral therapy-naïve subject over the first four years of HIV-1 infection. We found that CTL responses developed sequentially and required constant antigenic stimulation for maintenance.

Innate immune signaling induces high levels of TC-specific deaminase activity in primary monocyte-derived cells through expression of APOBEC3A isoforms.

In HIV-1-infected individuals, G-to-A hypermutation is found in HIV-1 DNA isolated from peripheral blood mononuclear cells (PBMCs). These mutations are thought to result from editing by one or more host enzymes in the APOBEC3 (A3) family of cytidine deaminases, which act on CC (APOBEC3G) and TC (other A3 proteins) dinucleotide motifs in DNA (edited cytidine underlined). Although many A3 proteins display high levels of deaminase activity in model systems, only low levels of A3 deaminase activity have been found in primary cells examined to date.

Human immunodeficiency virus type 1 mediates global disruption of innate antiviral signaling and immune defenses within infected cells.

Interferon regulatory factor 3 (IRF-3) is essential for innate intracellular immune defenses that limit virus replication, but these defenses fail to suppress human immunodeficiency virus (HIV) infection, which can ultimately associate with opportunistic coinfections and the progression to AIDS. Here, we examined antiviral defenses in CD4+ cells during virus infection and coinfection, revealing that HIV type 1 (HIV-1) directs a global disruption of innate immune signaling and supports a coinfection model through suppression of IRF-3. T cells responded to paramyxovirus infection to activate IRF-3 and interferon-stimulated gene expression, but they failed to mount a response against HIV-1.

Preservation of T cell proliferation restricted by protective HLA alleles is critical for immune control of HIV-1 infection.

HIV-1-infected persons with HLA-B27 and -B57 alleles commonly remain healthy for decades without antiretroviral therapy. Properties of CD8+ T cells restricted by these alleles considered to confer disease protection in these individuals are elusive but important to understand and potentially elicit by vaccination. To address this, we compared CD8+ T cell function induced by HIV-1 immunogens and natural infection using polychromatic flow cytometry.