A mouse T cell product that preferentially enhances IgA production. II. Physicochemical characterization.
Certain subsets of helper T cells, following stimulation with concanavalin A, secrete factors that specifically enhance the production of IgG1, IgE, and IgA by lipopolysaccharide-stimulated B cells. In the previous report, we describe a factor from the helper T cell line MB2-1 which enhances IgA production. IgA-enhancing factor has been purified from serum-free supernatants of this cell line. The purified lymphokine is a family of microheterogeneous polypeptides presumably modified post-translationally. IgA-enhancing factor has a native m.w. of 45,000 to 60,000 with subunits of between 24,000 and 28,000 under reducing conditions. Upon Edman degradation, a single amino-terminal sequence is detected which is identical to that of the lymphokine interleukin 5. IgA-enhancing factor activity is thus mediated by the same polypeptide that has been characterized as type II B cell growth factor, T cell-replacing factor, and eosinophil-differentiation factor.
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D007070:Immunoglobulin A / Q000096:biosynthesis*; D015848:Interleukin-5; D007378:Interleukins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D008970:Molecular Weight; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism*
D007070:Immunoglobulin A; D015848:Interleukin-5; D007378:Interleukins; D003208:Concanavalin A