Serum IgA Levels and Antinuclear Antibody Formation in Mice 1

Summary

Aged A/J mice, an autoimmune strain, develop increasing levels of serum IgA compared to aged DBA/1J mice, a nonautoimmune strain.

Adult thymectomy did not affect IgA levels in A/J and DBA/1J mice but accelerated anti-DNP antibody formation in A/J mice. These results can be explained by spontaneous loss of suppressor T cells which prevent the formation of anti-DNP antibodies in A/J mice.

Experiments involving thymectomized, irradiated mice reconstituted with irradiated thymus and bone marrow from donors of varying ages suggested that there are intrinsic changes and thymic epithelium function with age. Bone marrow cells from aged donors were not as effective in restoring IgA levels and suppressing anti-DNP antibody as those from young donors.

Thymic epithelium from aged donors was not as effective as that from young donors in suppressing the formation of anti-DNP antibodies.

The authors express their appreciation to Mrs. Jane Lyons, Tom Cable, and Mrs. Peggy Cook for technical assistance; to Mrs. Mona Myers and Ms. Wendy Pitt-man for typing and preparation of the tables; and to Dr. Bryan Gebhardt for a critical review of the manuscript.