Inhibition of bacterial adherence by secretory immunoglobulin A: a mechanism of antigen disposal.

Preparations of secretory iminunoglobuilin A (S-IgA) isolated from human parotid fluid specifically inhibited the adherence of Streptococcus strains to epithelial cells. Since bacterial adherence is a prerequisite for colonization of mucous surfaces. S-IgA-mediated inhibition of adherence would limit bacterial colonization. This mechanism can explain how secretory immunoglobulins function in the disposal of bacterial antigens.