CIRCULATING ANTIBODY-SECRETING CELL RESPONSE TO PARENTERAL PNEUMOCOCCAL VACCINES AS AN INDICATOR OF A SALIVARY IGA ANTIBODY-RESPONSE

This study assessed the mucosal immune response in healthy adult volun teers immunized parenterally with either pneumococcal polysaccharide ( N = 8) or pneumococcal polysaccharide-protein conjugate (N = 10) vacci ne with an aim to evaluate the relevance of antibody secreting cell (A SC) response after parenteral vaccination. An ASC response to the four types of capsular polysaccharide tested was observed in all vaccinees 7-9 days after immunization IgA was the predominant class in the ASC response, and IgG the next common, with very few IgM ASCs. The IgA/IgG ratio in the ASC response was higher after immunization with the poly saccharide than the conjugate vaccine. Antibodies of the IgA class wer e frequently seen in the saliva already before immunization; especiall y to serotypes 14 and 19F. A twofold increase of the type specific sec retory IgA antibodies in saliva was found in eight of the 16 instances in which the specific IgA ASC response was > 100 ASC per 10(6) cells and in only one of the 52 instances with fewer ASCs. We conclude that the ASC response in the peripheral blood is a useful parameter of the antibody response To pneumococcal vaccines and a good indicator of a s ecretory IgA response in the saliva. (C) 1997 Elsevier Science Ltd. Al l rights reserved.