A comparative study was carried out with the light chains of IgA and IgM from a single patient (SC). Both light chains were of κ type and were homogeneous. They were not distinguished by urea disc electrophoresis, amino acid composition, N-terminal amino acid sequence (consequently Vκ subgroup), Inv allotype and peptide map. Both were of VκIII subgroup which is found in very low frequency among human κ chains. It appears that both light chains of SC IgA and SC IgM were synthesized by the same genes (the same variable portion gene and the same constant portion gene).

1

This work was supported in part by Grant AI-8472 from the National Institute of Allergy and Infectious Diseases.

This content is only available via PDF.