ORIGINAL DESIGN: To evaluate the safety (clinical and immunologic) of rgp120/HIV-1IIIB vaccine (gp120 vaccine) immunization in healthy HIV-1 seronegative adult subjects. To compare the immune response to 100 mcg gp120 vaccine versus 300 mcg gp120 vaccine. To determine whether gp120 vaccine immunization causes a significant immune response as defined by specific parameters (e.g., induction of neutralizing antibodies to the IIIB isolate of HIV-1, gp120 antigen-specific lymphocytic proliferation).