Safety and immunogenicity study of Multiclade HIV-1 adenoviral vector vaccine alone or as boost following a multiclade HIV-1 DNA vaccine in Africa.

Background: We conducted a double-blind, randomized, placebo-controlled Phase I study of a recombinant replication-defective adenovirus type 5 (rAd5) vector expressing HIV-1 Gag and Pol from subtype B and Env from subtypes A, B and C, given alone or as boost following a DNA plasmid vaccine expressing the same HIV-1 proteins plus Nef, in 114 healthy HIV-uninfected African adults.

Methodology/principal Findings: Volunteers were randomized to 4 groups receiving the rAd5 vaccine intramuscularly at dosage levels of 1×10(10) or 1×10(11) particle units (PU) either alone or as boost following 3 injections of the DNA vaccine given at 4 mg/dose intramuscularly by needle-free injection using Biojector® 2000. Safety and immunogenicity were evaluated for 12 months.

Concordant proficiency in measurement of T-cell immunity in human immunodeficiency virus vaccine clinical trials by peripheral blood mononuclear cell and enzyme-linked immunospot assays in laboratories from three continents.

The gamma interferon (IFN-gamma) enzyme-linked immunospot (ELISPOT) assay is used routinely to evaluate the potency of human immunodeficiency virus (HIV) vaccine candidates and other vaccine candidates. In order to compare candidates and pool data from multiple trial laboratories, validated standardized methods must be applied across laboratories. Proficiency panels are a key part of a comprehensive quality assurance program to monitor inter- and intralaboratory performance, as well as assay performance, over time.

Evidence for Gag p24-specific CD4 T cells with reduced susceptibility to R5 HIV-1 infection in a UK cohort of HIV-exposed-seronegative subjects.

Aim: To characterize HIV-1 Gag p24-specific CD4 cell responses in HIV-exposed-seronegative (ES) individuals.

Methodology: Twelve ES individuals, of diverse ethnicity and wild type for the CCR5 Delta-32 mutation, were identified. Controls were HIV-negative blood donors.

Presence of HIV-1 Gag-specific IFN-gamma+IL-2+ and CD28+IL-2+ CD4 T cell responses is associated with nonprogression in HIV-1 infection.

HIV immunity is likely CD4 T cell dependent. HIV-specific CD4 T cell proliferative responses are reported to correlate inversely with virus load and directly with specific CD8 responses. However, the phenotype and cytokine profile of specific CD4 T cells that correlate with disease is unknown.