title: Oligomeric IgA: the major component of the in vitro primary response of mouse spleen fragments.
abstract: The primary antibody response elicited from mouse spleen explants by conjugates of the 3-nitro-5-iodo-4-hydroxyphenylacetic acid (NIP) hapten consisted mostly of the IgA class. Poly-L-lysine, pneumococcal polysaccharide Type SIII, keyhole limpet hemocyanin, and sheep erythrocytes were effective carriers in this system, whereas chicken globulin was not. The anti-NIP response against all of the immunogenic conjugates was detectable in culture media 4 days after explantation and immunization, and reached peak titers by 8-10 days. IgA was identified by sucrose gradient velocity centrifugation in conjunction with the use of a class-specific antiserum. The media collected at 4 days contained low titers of IgM antibody, whereas the peak response at 8 days consisted almost entirely of IgA. The primary response IgA secreted by the spleen fragments was characterized as polymeric by its sedimentation rate through a sucrose gradient, and as polyvalent by its drastically greater avidity for NIP(14)BSA than for free NIP-aminocaproic acid. Its haptenated phage-inactivating activity was abolished by treatment with 0.1 M 2-mercaptoethanol. These experiments indicate that precursor cells existing in the spleen before primary immunization can give rise to production of polymeric IgA.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D000917:Antibody Formation; D000921:Antibody-Producing Cells; D002352:Carrier Proteins; D046508:Culture Techniques; D005260:Female; D006241:Haptens; D007106:Immune Sera; D007070:Immunoglobulin A / Q000032:analysis / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000032:analysis; D007455:Iodine; D051379:Mice; D008810:Mice, Inbred C57BL; D009596:Nitrophenols; D010648:Phenylacetates; D013154:Spleen / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D002352:Carrier Proteins; D006241:Haptens; D007106:Immune Sera; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D009596:Nitrophenols; D010648:Phenylacetates; D007455:Iodine