Protection from immunodeficiency virus challenges in rhesus macaques by multicomponent DNA immunization

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Developing effective vaccines against human immunodeficiency virus (HIV) remains a global health priority.
• Multicomponent DNA vaccines offer a promising strategy for eliciting robust immune responses.
• Rhesus macaque models are crucial for evaluating vaccine efficacy against simian immunodeficiency virus (SIV) and simian-human immunodeficiency virus (SHIV).

Purpose of the Study:

• To evaluate the efficacy of multicomponent DNA vaccines against viral challenges in rhesus macaques.
• To assess the protective immune responses elicited by DNA vaccines encoding HIV env/rev and SIV gag/pol.
• To determine the impact of vaccination on viral replication, disease progression, and survival following pathogenic viral challenges.

Main Methods:

• Eight rhesus macaques were immunized with DNA vaccines encoding HIV env/rev and SIV gag/pol.
• Vaccinated and control macaques were challenged intravenously with cell-free SHIV IIIB.
• Protected animals were subsequently rechallenged with pathogenic SIV(mac239) and SHIV89.6P viruses.

Main Results:

• Three of eight vaccinated macaques were protected from the initial SHIV IIIB challenge, showing no detectable virus.
• All three protected animals remained virus-negative after subsequent challenges with pathogenic SIV(mac239) and SHIV89.6P.
• Control animals exhibited high viral loads, CD4+ T-cell loss, disease, and mortality, while vaccinated animals remained healthy.

Conclusions:

• Multicomponent DNA vaccines can elicit protective immune responses against highly pathogenic viral challenges in non-human primates.
• The observed Th1-type cellular immune responses in protected macaques suggest their critical role in viral control.
• These findings support the potential of multicomponent DNA vaccines as a viable strategy for combating HIV infection.