Cellular immune responses to mycobacteria in healthy and human immunodeficiency virus-positive subjects in the United States after a five-dose schedule of Mycobacterium vaccae vaccine

The safety and immunogenicity of heat-killed Mycobacterium vaccae vaccine were investigated in a pilot study assessing the feasibility of immunization to prevent mycobacterial disease in patients with human immunodeficiency virus (HIV) infection. Fifteen (seven healthy and eight HIV-positive subjects) received five doses of M. vaccae vaccine. Lymphocyte proliferation assays (LPAs) were performed using Mycobacterium avium sensitin (MAS) and M. vaccae sonicate (MVS). Vaccine was well tolerated in all 15 subjects with minimal induration at the vaccine site. LPAs for four of seven healthy vaccinees were positive for MAS after immunization. Median responses to MAS and MVS that were determined by LPAs were consistently higher for the eight HIV-positive vaccinees than for the seven healthy controls. A five-dose series of M. vaccae vaccine is safe for both healthy and HIV-positive subjects and deserves further evaluation as a vaccine to prevent HIV-associated mycobacterial disease.