Sheep Human secretory component (free and bound) Antibody

Purified IgG fraction of polyclonal sheep antiserum to human secretory component, free and bound. Secretory component is present in human secretions bound to secretory IgA (sIgA) and in free form. Secretory IgA (sIgA) functions as a dimer or polymer and accounts for almost all specific mucosal antibody activity. A molecule of sIgA is made up of two molecules of IgA, one J chain and one SC (MW 65,000) . The dimer IgA is transported into secretions by its binding to the SC on the epithelial cells. Under normal conditions, sIgA contains both subclasses IgA1 and IgA2, since both are capable of binding SC. Secretory component also has an affinity for polymeric IgM. Purified free human secretory component isolated from pooled milk is used for immunization. Freund's complete adjuvant is used in the first step of the immunization procedure.