Immune Mechanisms on Secretory Surfaces

Abstract

Immunoglobulins of all five classes are present in external secretions. The predominant one is secretory IgA, a unique form different from serum IgA. Among other differences, secretory IgA contains an interesting glycoprotein, “secretory component.” Secretory IgA antibody apparently is locally produced, but some other immunoglobulins in external secretions seemingly reach the lumina of secretory organs by diffusion. Other known or possible components of mucosal immune mechanisms are cellular immunity, the lysozyme-complement-immunoglobulin system, and interferon.