Nucleotide sequences of the variable regions of a human monoclonal antibody against HLA-A1, A23, and A24.

Abstract

Nucleotide sequences of the heavy and light chain variable (VH and VL) regions of a human monoclonal antibody (4-35-7), which recognized HLA-A1, A23 and A24, were determined by means of the reverse transcriptase-polymerase chain reaction. This antibody was generated by Epstein-Barr virus transformation of lymphocytes obtained from a multiparous donor, followed by fusion with mouse myeloma cells. The VH gene segment belonged to the VHIII gene family, and used the DXP4 and JH4 gene segments. This VH gene segment had 92.9% homology to the germline gene VH26, and contained 21 nucleotide substitutions. Fourteen of them generated the replacements of amino acids, while 7 failed to generate the replacement. The ratio of replacement to silent mutations in complementarity determining regions (CDRs) was 7.0. The VL gene segment belonged to the VkI gene family, and used Jk4. This VL gene segment showed 96.1% homology to the germline gene HK102, and contained 11 nucleotide substitutions. Seven of them generated the replacement of amino acids, while 4 failed to generate the replacement. The high ratio of replacement to silent mutations in CDRs of the VH gene segment suggested that the multiparity caused the processes of antigenic selection and somatic mutation, and generated this anti-HLA antibody.