HIV type 1 DNA development during long-term supervised therapy interruption.

We studied the pattern of HIV-1 DNA development and the association to other HIV-related factors during long-term supervised therapy interruption (LT-STI). Fifteen patients were treated with long-time protease inhibitor-based antiretroviral therapy (PI-ART). They had HIV-1 RNA at <50 copies/ml over 33.4 (SD 9.5) months and CD4(+) cell counts of 875 (SD 415) x 10(6)/liter. A real-time polymerase chain reaction, amplifying fragments of the HIV-1 pol gene and the human albumin gene simultaneously, was used to quantify HIV-1 DNA molecules in CD4(+) cells. The quantity of HIV-1 DNA in CD4(+) cells increased during LT-STI in all 15 patients, with an average doubling time of 2 months. Tentatively, three patterns were observed: rapid initial increase with subsequent stabilizing levels, rapid continuous increase, and slow increase. The HIV-1 DNA slope was positively related to the HIV-1 RNA maximum and steady state level and the baseline HIV-1 DNA value. It was inversely related to the decrease in CD4(+) cells both before the start of PI-ART and during the LT-STI. To conclude, HIV-1 DNA persists in infected CD4(+) cells despite long-term effective PI-ART and will increase after therapy interruption. The most important clinical predictor of long-term STI failure was the rapid CD4(+) cell decline before PI-ART. In patients with a steep pre-PI-ART slope it may be prudent to continue treatment and not initiate therapy interruption.

DNA mucosal HIV vaccine in humans.

This is a demonstration of immune activation by delivery of genetic vaccines in human mucosa. We analyzed the local and systemic responses in HIV-1 infected individuals following intraoral jet-injections of HIV-1 DNA constructs encoding the nef, rev, and tat regulatory genes. The immunological responses of the oral mucosa may be representative of other mucosal sites and was therefore selected for induction of mucosal reactivity by DNA immunization. The oral and intramuscular routes induced specific systemic T cell proliferative responses. Immunohistochemical analysis of oral biopsies 2 days after immunization revealed increased levels of granulocytes and T cells as well as expression of HLA-DR. T cell markers for CD3 +, CD4 + and CD8 + were significantly increased in the vaccinated mucosa. Vaccine-specific local and systemic antibodies were present during the immunization. However, increases were neither seen in the local or systemic titer nor in the B-cell accumulation in response to the immunizations. The presence of HIV-1 plasmid DNA was observed in mucosal biopsies as well as local proinflammatory T lymphocyte immune responses with predominantly IL-2 expression in the oral mucosal transudate.

CCR5 or CXCR4 is required for efficient infection of peripheral blood mononuclear cells by promiscuous human immunodeficiency virus type 2 primary isolates.

Primary human immunodeficiency virus type 2 (HIV-2) isolates are characterized by their ability to use a broad range of coreceptors, including CCR5, CXCR4, and several alternative coreceptors. However, the in vivo relevance of this in vitro promiscuity in coreceptor usage remains unclear. We set out to evaluate the relative importance of CCR5 and CXCR4 for infection of activated peripheral blood mononuclear cells (PBMC). PBMC from donors homozygous for wild-type CCR5 (CCR5(+/+) or CCR5Delta32 (CCR5(-/-)) were tested for their susceptibility to infection with 10 primary HIV-2 isolates with known coreceptor usage by parallel 50% tissue culture infectious dose (TCID50) titrations. Although all isolates, except one, were able to establish productive infection in CCR5(-/-) PBMC, the infection of these cells was inefficient for all isolates that were unable to use CXCR4. For CXCR4-using isolates there were only minor differences in TCID50 between CCR5(+/+) and CCR5(-/-) PBMC. When we compared the replication kinetics in PBMC from donors of the two genotypes we observed an average delay in replication onset of 9 days in the CCR5(-/-) PBMC. This study shows that HIV-2 can use alternative coreceptors for infection of PBMC, but that this infection is much less efficient than infection mediated by CCR5 or CXCR4. Thus, CCR5 and CXCR4 appear to be the major coreceptors for HIV-2 infection of PBMC.