title: The IgA subclass responses of human lymphocytes to B-cell activators.
abstract: The induction of IgA synthesis in normal peripheral blood lymphocytes cultured in the presence of 5 different B-cell activators was studied by immunofluorescence using monoclonal antibodies to the two subclasses. The surface phenotype of normal cells after overnight culture in the absence of mitogen showed a mean ratio IgA1:IgA2 of 2.7:1; cells with cytoplasmic IgA were very rare. Results obtained on different donors after stimulation showed considerable variation; IgA1 was the predominant subclass in Epstein-Barr virus-stimulated cultures, whereas pokeweed mitogen induced a predominantly IgA2 response; cells stimulated with Staphylococcus aureus, Branhamella catarrhalis and lipopolysaccharide and unstimulated cells showed a 1:1 ratio of the subclasses. It is concluded that in this system IgA subclass expression is a function of the activator employed.
mesh_terms: D000954:Antigens, Surface / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis* / Q000145:classification / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D007070:Immunoglobulin A