Idiotypic analysis of a monoclonal anti-Sm antibody. II. Strain distribution of a common idiotypic determinant and its relationship to anti-Sm expression
Pisetsky, D.S.; Semper, K.F.; Eisenberg, R.A.
Journal of Immunology 133(4): 2085-2089
1984
ISSN/ISBN: 0022-1767 PMID: 6206150 Document Number: 231345
The idiotypes borne by Y2, a monoclonal anti-Sm antibody of MRL-lpr/lpr mouse strain origin, were investigated to elucidate genetic mechanisms in this autoantibody response. An anti-Y2 anti-idiotypic antiserum was raised in a rabbit and was rendered specific for idiotype by extensive absorption with globulins of the B6 and BALB/c strains as well as the BALB/c myeloma UPC 10. By using a sensitive assay for idiotype by inhibition enzyme-linked immunosorbent assay (ELISA), the Y2 determinant was found to be commonly expressed in sera of MRL-lpr/lpr and MRL-+/+ mice. Sera of several normal strain mice also bore the idiotype and, in mice bearing the lpr gene, idiotype levels were increased 1.5- to 5-fold, even in the absence of a serum anti-Sm response. The relationship of this idiotype to anti-Sm expression was further assessed by determining the idiotype content of affinity-purified anti-Sm antibodies from MRL-lpr/lpr mice. Anti-Sm from serum pools or individual animals showed no significant enrichment of the Y2 idiotype in comparison to unselected MRL-lpr/lpr IgG. Thus, the Y2 idiotype defines only a minor component of the anti-Sm autoantibody response, and most antibodies with this determinant express other antigenic specificities.