Antibody Response in Bronchoalveolar Lavage and Serum of Rats after Aerosol Immunization of the Airways with a Well-Adhering and a Poorly Adhering Strain of <i>Streptococcus pneumoniae</i>

This study describes the antibody response to two bacterial antigens, pneumolysin toxoid (PL) and purified pneumococcal capsular polysaccharide (PPS) 19F, in bronchoalveolar lavage (BAL) and in serum in rats after aerosol immunization with whole killed Streptococcus pneumoniae. To study the importance of bacterial adherence for antibody formation, one well-adhering and one poorly adhering strain of S. pneumoniae was used. The results show local specific anti-PPS 19F IgA, IgM and IgG antibody activities after aerosol immunization. Anti-PL antibody activity in all three immunoglobulin classes was found, although the anti-PL activity was lower than the anti-PPS 19F antibody activity. The IgA anti-PPS 19F antibody activity in BAL after immunization with the well-adhering strain was higher than with the poorly adhering strain. We conclude that aerosol immunization with S. pneumoniae induces a local, specific antibody production in the lung of the rat.