DNA vaccination by intradermal electroporation induces long-lasting immune responses in rhesus macaques

Background A desirable HIV vaccine should induce protective long‐lasting humoral and cellular immune responses. Methods Macaques were immunized by env DNA, selected from a panel of recently transmitted SIVmac251 Env using intradermal electroporation as vaccine delivery method and magnitude, breadth and longevity of humoral and cellular immune responses. Results The macaques developed high, long‐lasting humoral immune responses with neutralizing capacity against homologous and heterologous Env. The avidity of the antibody responses was also preserved over 1‐year follow‐up. Analysis of cellular immune responses demonstrated induction of Env‐specific memory T cells harboring granzyme B, albeit their overall levels were low. Similar to the humoral responses, the cellular immunity was persistent over the ~1‐year follow‐up. Conclusion These data show that vaccination by this intradermal DNA delivery regimen is able to induce potent and durable immune responses in macaques.