CELL-MEDIATED AND HUMORAL IMMUNE-RESPONSES INDUCED BY SCARIFICATION VACCINATION OF HUMAN VOLUNTEERS WITH A NEW LOT OF THE LIVE VACCINE STRAIN OF FRANCISELLA-TULARENSIS

Tularemia is a disease caused by the facultative intracellular bacterium Francisella tularensis. We evaluated a new lot of live F. tularensis vaccine for its immunogenicity in human volunteers. Scarification vaccination induced humoral and cell-mediated immune responses. Indications of a positive immune response after vaccination included an increase in specific antibody levels, which were measured by enzyme-linked immunosorbent and immunoblot assays, and the ability of peripheral blood lymphocytes to respond to whole F. tularensis bacteria as recall antigens. Vaccination caused a significant rise (P < 0.05) in immunoglobulin A (IgA), IgG, and IgM titers. Lymphocyte stimulation indices were significantly increased (P < 0.01) in vaccinees 14 days after vaccination. These data verify that this new lot of live F. tularensis vaccine is immunogenic.