SIV DNA VACCINE TRIAL IN MACAQUES - POST-CHALLENGE NECROPSY IN VACCINE AND CONTROL-GROUPS

In this study we describe the histopathologic findings from nine macaq ues in a simian immunodeficiency virus (SIV) DNA vaccine trial evaluat ing the ability of a 5-plasmid DNA vaccine to protect against an unclo ned SIVmac251 challenge (Lu et al., J. Virol. 1996, 70, 3978-3991). Th ree vaccinated and one control macaque developed disease and were euth anized in the first year following challenge. The other four vaccinate d and one control macaque remained clinically normal and were euthaniz ed at the end of the trial (60 weeks post-challenge). The necropsy dat a revealed that both diseased and clinically normal macaques had devel oped typical SIV-related lymphoid changes, inflammatory disorders and opportunistic infections. All animals had variable degrees of follicul ar and/or paracortical lymphoid hyperplasia suggesting immune activati on. All but one vaccinated macaque and both control macaques had SIV-a ssociated opportunistic infections. Within the small groups of animals , the ability to contain opportunistic infections was superior, and th e overall lymphoid changes less severe, in the macaques that had recei ved vaccine DNAs by three routes of inoculation (intravenous, intramus cular and gene gun) than in those that had received control DNAs or va ccine DNAs by gene gun only. In the future it will be important to fur ther test how the route and method of DNA inoculation impact the effic acy of immunodeficiency virus vaccines. (C) 1997 Elsevier Science Ltd.