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The HIV Vaccine Trials Network (HVTN) conducts clinical trials on 4 continents in pursuit of a safe and effective HIV vaccine. Cellular immune responses to vaccination that define vaccine immunogenicity and/or immune correlates of protection can be measured using multiparameter intracellular cytokine staining (ICS) assays. The HVTN cellular immunology laboratory, located in Seattle, WA, conducts ICS assays for vaccine trials according to Good Clinical Laboratory Practices (GCLP). In 2013, the HVTN established a second GCLP compliant cellular immunology laboratory in Cape Town, South Africa to assess vaccine immunogenicity for HVTN trials conducted on the African continent. To ensure ICS readouts in the 2 laboratories were directly comparable, we conducted concordance testing using PBMC from healthy controls and vaccine trial participants. Despite standardized procedures and instrumentation, shared quality control measures and quality assurance oversight, several factors impacted our ability to obtain close agreement in T‐cell responses measured in the 2 laboratories. One of these was the type of fetal bovine serum (FBS) used in the assay, which impacted lymphocyte cell viability and background responses. In addition, the differences in supernatant removal technique also significantly affected our ability to detect positive responses to vaccine antigens. Standardization of these factors allowed us to achieve and maintain ICS assay concordance across the 2 laboratories over multiple years, accelerating our efforts to evaluate HIV vaccines. The insights gained in this process are valuable for assay transfer efforts by groups of investigators that need to directly compare data generated in different laboratories around the globe. [ABSTRACT FROM AUTHOR]

Background The Pox-Protein Public-Private Partnership is performing a suite of trials to evaluate the bivalent subtype C envelope protein (TV1.C and 1086.C glycoprotein 120) vaccine in the context of different adjuvants and priming agents for human immunodeficiency virus (HIV) type 1 (HIV-1) prevention. Methods In the HIV Vaccine Trials Network 111 trial, we compared the safety and immunogenicity of DNA prime followed by DNA/protein boost with DNA/protein coadministration injected intramuscularly via either needle/syringe or a needle-free injection device (Biojector). One hundred thirty-two healthy, HIV-1–uninfected adults were enrolled from Zambia, South Africa, and Tanzania and were randomized to 1 of 6 arms: DNA prime, protein boost by needle/syringe; DNA and protein coadministration by needle/syringe; placebo by needle/syringe; DNA prime, protein boost with DNA given by Biojector; DNA and protein coadministration with DNA given by Biojector; and placebo by Biojector. Results All vaccinations were safe and well tolerated. DNA and protein coadministration was associated with increased HIV-1 V1/V2 antibody response rate, a known correlate of decreased HIV-1 infection risk. DNA administration by Biojector elicited significantly higher CD4+ T-cell response rates to HIV envelope protein than administration by needle/syringe in the prime/boost regimen (85.7% vs 55.6%; P =.02), but not in the coadministration regimen (43.3% vs 48.3%; P =.61). Conclusions Both the prime/boost and coadministration regimens are safe and may be promising for advancement into efficacy trials depending on whether cellular or humoral responses are desired. Clinical Trials Registration South African National Clinical Trials Registry (application 3947; Department of Health [DoH] no. DOH-27–0715–4917) and ClinicalTrials.gov (NCT02997969). [ABSTRACT FROM AUTHOR]

In the classic `two-signal' model for B cell activation, signal 1 through the antigen receptor plus signal 2 through lymphokine receptors and CD40 leads to proliferation, but signal 1 alone leads to tolerance or anergy. In a protocol designed to deliver signal 1 in vitro with anti-δ without signal 2, purified small dense B cells from untreated mice exposed to any of three monoclonal anti-δ antibodies or to polyclonal anti-δ in vitro showed modest S phase entry at 50 μg/ml. In contrast, at low doses (0.1–0.5 μg/ml) of anti-δ, there was no cell cycle entry at 64 h, but apoptosis was accelerated at 16 h. Polyclonal anti-μ and three monoclonal anti-μs did not show this early apoptosis induction. Anti-CD40 and IL-4 inhibited apoptosis in B cells treated with 0.5 μg/ml anti-δ and increased S phase entry at 10 μg/ml anti-δ. Low-dose anti-δ (but not anti-μ) induced increased B7-2 and class II MHC expression on a subset of B cells, many of which were in apoptosis. Larger transient increases in c-Myc and Egr-1 expression were seen with low-dose anti-δ than with anti-μ, followed by an abrupt fall below baseline, a sequence previously linked to apoptosis. There was no change in Bcl-2, Bcl-xL or Bax. These data suggest a functional difference between δ and μ cross-linking on resting spleen B cells. A BCR stimulus sufficient for early activation events, but insufficient for full G1 entry, may lead to apoptosis. [ABSTRACT FROM PUBLISHER]