New insights into HIV-1 specific cytotoxic T-lymphocyte responses in exposed, persistently seronegative Kenyan sex workers

Human immunodeficiency virus (HIV)-2-specific T lymphocyte proliferative responses in HIV-2-infected and in HIV-2-exposed but uninfected individuals in Guinea-Bissau

“…showed a significant inverse correlation between the level of CTL activity and proviral DNA load, indicating a role for CTL in the control of the HIV-2 infection [44]. The finding of viral-specific cell-mediated immune responses, as measured by T cellproliferation in HIV-2 EU individuals, is consistent with studies of HIV-1 EU individuals, including homosexual men [5], children born to HIV-1-infected women [6], HIV-1 discordant couples [7] and highly exposed sex workers [8,[12][13][14][15][16][17], demonstrating HIV-1-specific T helper cell responses and/or CTL in a proportion of these individuals. The observations in the present study provide further indications for a role of cell-mediated immune responses in the control of HIV-2 infection and are in line with the view of HIV-2 infection resembling the cases with a less progressive HIV-1 infection, often termed long-term non-progressors.…”

“…This may be due to virological factors leading to the lower viral load usually accompanying HIV-2 infection [35][36][37][38][39][40], but other factors such as a more efficient immune response against HIV-2 may be involved (or both) (reviewed in [41]). Perhaps multiple exposures to low doses of virus are more likely to give rise to a protective immune response, such as in the HEPS cohort in Nairobi [13][14][15][16][17]. We can only speculate as to whether or not the HIV-2-specific immune responses detected in the present study represent a true protective mechanism.…”

“…As in other viral infections [3,4], cell-mediated immunity (CMI) appears to play a crucial role; HIV-1-specific cytotoxic T lymphocytes (CTL) as well as lymphoproliferative responses have been demonstrated in several groups of HIV-1-exposed uninfected (EU) individuals and in HIV-1-infected long-term non-progressors (LTNP) [4][5][6][7][8][9][10][11][12][13][14][15][16]. This includes the wellcharacterized group of HIV-exposed persistently seronegative (HEPS) commercial sex workers (CSW) in Nairobi, Kenya [13][14][15][16][17]. AIDS vaccine studies in monkey models have also provided insight into the importance of CMI in the specific immunity to HIV and the related simian immunodeficiency virus [SIV; [18][19][20][21][22].…”

A Period of Transient Viremia and Occult Infection Precedes Persistent Viremia and Antiviral Immune Responses during Multiple Low-Dose Intravaginal Simian Immunodeficiency Virus Inoculations

“…In fact, there are no credible reports of a lentiviral infection being cleared in any host by any means, although the infections may become undetectable in peripheral blood with standard assays and thus remain hidden. In a condition that is very similar to the occult infection in IVAG low-dose SIV-inoculated monkeys, HIV-specific systemic cellular and local immune responses have been detected in seronegative individuals repeatedly exposed to HIV (2,5,15,16), and HIV DNA is present at very low levels in PBMC of repeatedly exposed (19), persistently seronegative individuals. Thus, occult HIV infections that produce transient periods of viremia that are undetectable by routine clinical tests probably occur much more frequently than is generally appreciated.…”

Expression and Immunogenicity of Sequence-Modified Human Immunodeficiency Virus Type 1 Subtype BpolandgagpolDNA Vaccines

“…ϩ T-cell responses and HIV disease progression (7,8,14,29,31,33,44,46). Moreover, vaccine approaches specifically designed to induce strong cellular immunity recently have shown promising results in nonhuman primate vaccine challenge models (2,5,49).…”