How important is the 'quality' of the cytotoxic T lymphocyte (CTL) response in protection against HIV infection?

Cytotoxic T lymphocyte (CTL) responses have been associated with protection from HIV-1 infection in people with a high degree of exposure to HIV and w ho show no serological evidence of HIV infection (HEPS, highly exposed pers istently seronegative). However, it remains unclear how protective CTL resp onses could apparently develop in a minority of people, whilst the great ma jority of HIV-infected people make strong CTL responses yet progress to AID S and death. In this paper we review the data which supports the hypothesis that the quality of the T-cell response, rather than its magnitude, may be an important factor that merits further investigation. (C) 2001 Elsevier S cience B.V. All rights reserved.