Role of Circulating T Follicular Helper Cells and Stem-Like Memory CD4 T Cells in the Pathogenesis of HIV-2 Infection and Disease Progression.

CD4 T cells are critical players in the host adaptive immune response. Emerging evidence suggests that certain CD4 T cell subsets contribute significantly to the production of neutralizing antibodies and help in the control of virus replication. Circulating T follicular helper cells (Tfh) constitute a key T cell subset that triggers the adaptive immune response and stimulates the production of neutralizing antibodies (NAbs).

Genetic Characterization of Full-Length HIV-2 Long Terminal Repeat Sequences: Identification of Rare Promoter Variants.

In this study, we sequenced the full-length HIV type 2 (HIV-2) long terminal repeat region from the proviral DNA of 23 HIV-2-infected individuals from the southern parts of India. We identified two different promoter variant strains circulating in this region along with the globally circulating common promoter variant. Seven sequences had an additional nuclear factor kappa-light chain enhancer of activated B cells (NF-κB) binding motif and the sequence from another subject showed one NF-κB and one RBE-III binding site.

Cross Type Neutralizing Antibodies Detected in a Unique HIV-2 Infected Individual From India.

Infection with HIV-2, a retrovirus that is closely related to HIV-1, is characterized by slower disease progression and transmission, longer latency period and low or undetectable viremia. Host immunity, including production of potent neutralizing antibodies, may be one of the possible contributors to the distinction between the two infections. In an attempt to understand whether HIV-2 infection results in production of neutralizing antibodies and to characterize the nature of the neutralization response we screened plasma of 37 HIV-2 infected individuals for the presence of broadly neutralizing antibodies.

Induction of circulating T follicular helper cells and regulatory T cells correlating with HIV-1 gp120 variable loop antibodies by a subtype C prophylactic vaccine tested in a Phase I trial in India.

A Phase I HIV-1 vaccine trial sponsored by the International AIDS Vaccine Initiative (IAVI) was conducted in India in 2009 to test a subtype C prophylactic vaccine in a prime-boost regimen comprising of a DNA prime (ADVAX) and MVA (TBC-M4) boost. The trial demonstrated that the regimen was safe and well tolerated and resulted in enhancement of HIV-specific immune responses. Preliminary observations on vaccine-induced immune responses were limited to analysis of neutralizing antibodies and IFN-γ ELISPOT response.

Differential Codon Usage Pattern of HIV-1 tat Gene in Those with Slower and Faster Rates of Disease Progression.

Codon usage has been identified as one of the most important factors that influence gene expression. The frequencies with which the different codons are used vary significantly between different organisms and also between the genes within the same organism. HIV has a remarkable nucleotide composition with an above average percentage of "A" nucleotides resulting in a codon usage pattern different from that of the human host.

Molecular Characteristics of the Envelope of Vertically Transmitted HIV-1 Strains from Infants with HIV Infection.

Mother-to-child transmission (MTCT) of HIV offers a good opportunity to study the dynamics of early viral evolution in the host environment to which the virus has partially adapted. Such studies would throw light on the unique features of the infecting viruses, which will subsequently help to design preventive or therapeutic measures against the newly infecting and evolving strains of HIV. Therefore, we undertook a study to determine the genetic divergence of proviral envelope sequences from the HIV-infected infants (<2 years).