Suppression of Chicken Immunoglobulin Ontogeny by F(ab′) 2 Fragments of Anti-μ Chain and by Anti-L Chain

Serum IgM, IgY and IgA were suppressed by the embryonic administration of F(ab′)2 fragments of goat anti-μ followed by bursectomy at hatch, indicating that the Fc fragment is not essential for antibody-mediated class suppression in chickens. Anti-L chain was also capable of mediating suppression but anti-IgY H chain was not, indicating that the mechanism for suppression involves specific binding to IgM-producing cells rather than a toxic effect of antibody-antigen complexes. At the doses used, both F(ab′)2 anti-μ and intact anti-L antibody caused more marked suppression of IgA than of IgM and IgY.