Germ-line affinity and germ-line variable-region genes in the B cell response

Autor: M M Chua, S H Goodgal, F Karush
Rok vydání: 1987
Předmět:
Zdroj: The Journal of Immunology. 138:1281-1288
ISSN: 1550-6606
0022-1767
DOI: 10.4049/jimmunol.138.4.1281
Popis: The predominance of germ-line genes in IgM expression was evaluated from the nucleotide sequences of mRNA, derived from 10 hybridoma cell lines, coding for the VH and VL regions of anti-5-dimethylaminonaphthalene-1-sulfonyl (anti-Dns) IgM antibody. At least six germ-line VH gene segments distributed among four families are used in this response. Seven of the 10 independently rear-ranged VH genes were identified as germ line, with the other three possibly germ line. In all of them the D and JH portions retained the germ-line sequences of the D and JH segments from which they were derived. Maximum diversity was found in the D segments and the use of noncoded nucleotides at the VH-D and D-JH junctions. Of the eight cell lines expressing the lambda light chains, all were germ line and involved the three subtypes. Maximum affinity for the homologous ligand was found among the seven cell lines identified as expressing germ-line gene segments. Thus any somatic mutation among the remaining 3 cell lines did not provide enhanced affinity and the observed affinity of each cell line can be described as germ-line affinity. It is further suggested that the anti-Dns selectivity of the IgM antibodies is associated primarily with the CDR3 regions.
Databáze: OpenAIRE