Therapeutic immunization in HIV infection

Abstract

The antiretroviral therapy efficacy remains unquestioned, though associated with drug resistance, toxicity and high costs. Several strategies of therapeutic immunization are being explored to limit time on treatment and prevent disease progression by increasing the immunological control of HIV. Research on immune correlates of protection suggests that boosting the HIV-specific T cells with vaccines should combine amplification of specific effector and memory T cells. Trials with inactivated virus particles, peptides or naked DNA boosted HIV-specific CD4 T cells and showed moderate effects on virus replication but require, however, adjuvantation or combination with other vaccines. Most clinical trials evaluating recombinant live vectors used so far the HIV-recombinant canarypox with immunogenicity for HIV-specific CD4 and CD8 T cells. Significant virus control or prolongation of treatment interruptions was repeatedly observed in the antiretroviral therapy-treated chronically infected patients but not in the acutely infected ones. Infusions of autologous dendritic cells loaded with inactivated autologous HIV showed promising results in chronically infected patients. The better efficacy of therapeutic immunization in chronic infection raises questions while those encouraging, though still modest, results prompt development of stronger vaccine candidates to optimize such strategy.