A phase I, randomized study of combined IL-2 and therapeutic immunisation with antiretroviral therapy.

BACKGROUND: Fully functional HIV-1-specific CD8 and CD4 effector T-cell responses are vital to the containment of viral activity and disease progression. These responses are lacking in HIV-1-infected patients with progressive disease. We attempted to augment fully functional HIV-1-specific CD8 and CD4 effector T-cell responses in patients with advanced chronic HIV-1 infection. DESIGN: Chronically infected patients with low CD4 counts T-cell counts who commenced antiretroviral therapy (ART) were subsequently treated with combined interleukin-2 and therapeutic vaccination. METHODS: Thirty six anti-retroviral naive patients were recruited and initiated on combination ART for 17 weeks before randomization to: A) ongoing ART alone; B) ART with IL-2 twice daily for 5 days every four weeks starting at week 17 for 3 cycles; C) ART with IL-2 as in group B and Remune HIV-1 vaccine administered once every 3 months, starting at week 17; and D) ART with Remune vaccine as in group C. Patients were studied for 65 weeks following commencement of ART, with an additional prior 6 week lead-in observation period. CD4 and CD8 T-cell counts, evaluations of HIV-1 RNA levels and proliferative responses to recall and HIV-1 antigens were complemented with assessment of IL-4-secretion alongside quantification of anti-HIV-1 CD8 T-cell responses and neutralizing antibody titres. RESULTS: Neither IL-2 nor Remune vaccination induced sustained HIV-1-specific T-cell responses. However, we report an inverse relationship between HIV-1-specific proliferative responses and IL-4 production which continuously increased in patients receiving immunotherapy, but not patients receiving ART alone. CONCLUSION: Induction of HIV-1-specific cell-mediated responses is a major challenge in chronically HIV-1-infected patients even when combining immunisation with IL-2 therapy. An antigen-specific IL-4-associated suppressive response may play a role in attenuating HIV-specific responses.

A CMV DNA vaccine primes for memory immune responses to live-attenuated CMV (Towne strain).

CMV-seronegative subjects vaccinated intramuscularly or intradermally with a DNA vaccine encoding pp65, IE1, and gB were administered live-attenuated CMV (Towne) to characterize immune priming by the DNA vaccine. CMV-specific memory T-cells (detected by standard ELISPOT assay in only 20% of subjects) were detected by IFN-gamma cultured ELISPOT assay in 60% of subjects primed intramuscularly and correlated with immune responses after Towne. The median time to first pp65 T-cell and gB antibody response after Towne was 14 days for DNA-primed subjects vs. 28 days for controls administered Towne only (p=0.02 and 0.03, respectively). Furthermore, there was a trend toward more DNA-vaccinated subjects than controls developing a gB-specific IFN-gamma T-cell response after Towne administration (47% vs. 0%, p=0.06).