An International Symposium concerning the secretory immune system and caries immunity was hosted by the Institute of Dental Research and The School of Dentistry at The University of Alabama in Birmingham, Alabama. Particular emphasis was given to aspects of secretory immunity including, the induction of an immune response, cellular events involved in differentiation and function of mucosal antibodies. Major emphasis was also given to the most recent advances in studies of bacterial antigens of importance in ecology, pathogenesis and immunity. Encouraging results from several laboratories indicate that the major goal - induction of protective immunity in external secretions - is attainable. This particularly concerns immunity to dental caries, the gastrointestinal enteropathies, and respiratory and urogenital infections. As a result of this meeting, the summation committee suggested future avenues of most relevant and productive research in the field of secretory immunity and infection.