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SERUM IgM/A, IgA AND FUNCTIONALLY DISTINCT IgM ANTI‐TYPE III PNEUMOCOCCAL POLYSACCHARIDE (SIII) ANTIBODIES IN BALB/c AND ATHYMIC (NUDE) MICE
Author(s) -
Kearney R,
Johnstone S
Publication year - 1984
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1984.66
Subject(s) - antibody , balb/c , immunoglobulin m , antigen , chemistry , immunology , biology , microbiology and biotechnology , immunoglobulin g , immune system
Summary The influence of hereditary absence of thymus upon the synthesis of IgA, complement‐fixing (CF) hybrid IgM/A, CF‐IgM and non‐CF‐IgM antibodies to pneumococcal type III polysaccharide (SIII) injected into BALB/c and athymic nude mice was studied. Techniques Involved the differential absorption of the serum antibodies by protein‐A of Staphylococcus aureus (Sa), co‐precipitation in gels with 125 I‐SIII and autoradiography. IgM/A anti‐SIII activity was not demonstrable in nude mice but was produced in significant amounts, by day 5 in BALB/c mice injected with SIII. By day 8, node mice produced more IgA anti‐SIII antibodies than BALB/c mice injected with the same antigen. IgA anti‐SIII antibodies were not detected in either strain 5 days after SIII administration. The absence of hybrid IgM/A anti‐SIII antibodies in athymic mice, prior to the appearance of monotypic IgA anti‐SIII antibodies at day 8, suggests that IgM/A and not IgA synthesis is largely T cell‐dependent The evidence also implies that hybrid IgM/A antibody production, maximal on day 5 in BALB/c mice, and absent from nude mice, is not an essential produced in the switching from IgM to IgA synthesis. Both strains of mice produced comparable amounts of complement‐fixing (CF)‐IgM and NCF‐IgM anti‐SIII antibodies, with the production of non‐complement‐fixing (NCF)‐IgM anti‐SIII in athymic mice being delayed. Results indicate that attemptS to quantitate the levels of IgA by assays incorporating anti‐IgA anti‐sera may be complicated by the presence of IgM/A hybrid antibody. The lower levels of IgA in nude mice may not necessarily imply T cell dependency of IgA synthesis. Since cells producing the T cell‐dependent IgM/A antibodies are visualized by direct plagues, the present findings have important implications in studies where the calculation of the number of indirect plaque‐forming cells is based on the assumption that direct plaques are due only to thymus‐independent CF‐IgM antibodies.