Immune responses in asymptomatic HIV-1-infected patients after HIV-DNA immunization followed by highly active antiretroviral treatment

Intensive chemotherapy is capable of reducing the viral load in HIV-l-infec ted individuals while infected cells are still present. A special property of DNA immunization is to induce both new CTL and Ab responses. We evaluate d the possibility of inducing new immune responses in already infected indi viduals by means of DNA constructs encoding the nef, rev, or tat regulatory HIV-1 genes. Significant changes in viral loads and CD4(+) counts were obs erved in four patients,tho started highly active antiretroviral treatment ( HAART) during the immunization study. The DNA immunization induced Ag-speci fic T cell proliferation, which persisted up to 9 mo after the last DNA inj ection, and cytolytic activities but did not, by itself, reduce viral load. Increased levels of CTL precursor cells were induced in all nine DNA-immun ized patients. The profile of IFN-gamma secretion observed when human PBMC were transfected with the nef, rev and tar DNA resembled that found in the CTI, activity (nef > tat > rev). Ab responses that occurred after immunizat ions were of a low magnitude. In accordance with the high IL-6 production i nduced by the nef DNA plasmid, IgG titers were highest in patients immunize d with nef DNA, The initiation of HAART appears to contribute to the induct ion of new HIV-specific CTL responses, but by itself did not cause obvious re-induction of these activities.