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Experimental Vaccine Temporarily Halts HIV
Researchers in Barcelona, Spain, have reported promising results with a therapeutic vaccine designed to halt the growth of the human immunodeficiency virus (HIV) in infected patients. The vaccine was developed from immune cells exposed to heat-inactivated HIV.
The new study — published in Science Translational Medicine — involved patients in the early stages of HIV-1 infection who were being treated with combination antiretroviral therapy (cART). Thirty-nine immunocompromised individuals (CD4+ > 450 cells/mm3) were randomly assigned to receive three immunizations with a therapeutic vaccine consisting of autologous monocyte-derived dendritic cells (MD-DCs) pulsed with autologous heat-inactivated whole HIV or with nonpulsed MD-DCs.
Vaccination with the pulsed immune cells was shown to shift the virus–host balance, according to the authors. At 12 weeks after the interruption of cART, the plasma viral load was reduced in 12 of 22 patients (55%) given HIV-pulsed MD-DCs versus 1 of 11 patients (9%) treated with nonpulsed MD-DCs. At 24 weeks, the corresponding proportions of patients with reduced plasma viral loads were 35% and 0%. The decreased viral loads with the pulsed MD-DC vaccine were associated with a consistent increase in HIV-1–specific T cell responses, the authors noted.
After 1 year, however, the vaccine was no longer effective, and the patients had to return to their cART regimens. Nevertheless, the authors say, their findings justify “further investigation of new candidates and/or new optimized strategies of vaccination with the final objective of obtaining a functional cure as an alternative to cART for life.”
Source: Science Translational Medicine; January 2, 2013.