Ex Vivo Expansion of HIV Type 1-Specific Cytolytic T Cells from HIV Type 1-Seropositive Subjects

Cytotoxic T lymphocytes that specifically lyse HIV-1-infected cells occur at uncommonly high frequency in the blood of infected individuals. The CTL response is dominated by the recognition of a small number of peptides encoded by HIV-1 structural and regulatory genes. These two facts have enabled us to develop potent HIV-specific CTL lines from the blood of infected patients without AIDS opportunistic infections by ex vivo culture of nonspecifically stimulated T cell lines with autologous antigen-presenting cells (APCs) preincubated with immunodominant HIV-1 peptides. After one selection, HIV-specific cytotoxicity is enhanced 1.4-to sixfold. Frequency analysis of the T cell line from 1 patient revealed that after exposure to peptide-incubated autologous B-LCLs, the frequency of CTLs specific for the gp160-expressing APCs was enhanced 6-fold and, after a second exposure, 11-fold compared to the nonselected T cell line. Because the APCs used for the frequency analysis were EBV-transformed B-LCLs, some of the specific CTLs in the culture recognized the EBV-expressing APCs. HIV-specific cytotoxicity is enhanced without augmentation of EBV-specific cytotoxicity when PBMCs are used as APCs. Because T cell lines enhanced for HIV-1 specificity are highly cytotoxic and can be expanded to approximately 10⁹-10¹⁰ cells/ml of blood, they may be useful for laboratory research or for immunotherapy.