Maternal and infant CD4 and CD8 T cell responses across the genome of HIV-1 subtype C in South Africa.
Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. A10185)
Tiemessen CT, Shalekoff S, Meddows-Taylor S, Bendezi N, Lalsab S, Anthony F, Gray GE, Kuhn L Aids Virus Research Unit, National Institute for Communicable Diseases, Johannesburg, South Africa
Background. Little is known about the spectrum of HIV-specific immune responses in HIV exposed-uninfected infants. This study was therefore undertaken to assess T cell immune reactivity across the HIV genome of HIV exposed-uninfected infants and their mothers. Methods. Heparinized whole blood samples obtained from12 HIV-infected mothers and their 13 infants at delivery were analysed by Intracellular Cytokine Assay for their CD4 and CD8 T cell responses to pools of overlapping subtype C peptides (15-mers overlapping by 11 amino acids) representing Gag, Pol, Nef, the Regulatory regions combined (Rev, Tat, Vpu, Vif and Vpr) and Env. Results. 5/13 (38.5%) infants showed a CD8 T cell response to at least one region (one infant responded to all regions, one to Gag, Nef and Env, and 3 to one pool only: one to Reg and 2 to Env). CD4 T cells of 4/13 (30.8%) infants showed reactivity, 3 of whom responded to one region only (Gag, Nef, Env) and one infant responded to all protein regions. CD8 T cells of all HIV-infected mothers responded to 3 or more protein regions, with CD4 T cells of 11/12 mothers responding to one or more protein regions. Infants that displayed detectable responses had profiles of immune reactivity that were distinct from that of their mothers. Conclusions. Approximately 30-40% of HIV exposed-uninfected infants showed T cell reactivity to HIV, in general with a weak and narrow response profile. This contrasted with stronger responses and the broader targeting of most regions of the HIV genome found in HIV-infected mothers. Understanding infants' responses to in vivo challenge with HIV may assist in the design and evaluation of preventative HIV vaccines.
Keywords: AEGIS, Antigens, CD8, HIV-1, CD8-Positive T-Lymphocytes, Antigens, CD4, Acquired Immunodeficiency Syndrome, HIV, HIV Seropositivity, HIV Infections, AIDS Vaccines, Genes, gag, HIV Antigens, Genes, tat, Genes, env, Mothers, Gene Products, tat, South Africa, Infant, Humans, immunology, genetics
