The primary objective of this research is to develop an immunogen capable of inducing protection in man against gonorrheal infection. To this end, crude antigen preparations from gonorrheal isolates will be examined to detect components that may be virulence-associated, or type- specific, or both. Such components will be purified and examined for their ability to induce active immune responses in experimental animals and to elicit the production of antibodies in both animals and man capable of bactericidal, opsonizing and/or protective activities against virulent gonococci.