정상 성인의 말초 혈액 림프구에 표현된 Humkv325-derived κ 경쇄에서의 N-region addition = N-region Addition in Humkv325-derived Kappa Chain Transcripts Expressed in the PBLs of Normal Individuals

다국어 초록 (Multilingual Abstract)

Complementarity determining region(CDR3) of immunoglobulin is the center of antigen binding site. Changes in the number of amino acids of CDR3 may result in change in antigen binding specificity and affinity. The majority of immunoglobulin x chain has 9 or 10 amino acid co-dons in the CDR3 region. Immunoglobulin x chain containing CDR3 with 11 amino acid codons cannot be made without N-region addition. The aims of this study were to evaluate the presence of immunoglobulin x light chain with 11 amino acid codons in its CDR3 domain expressed in the peripheral blood lymphocytes(PBLs) of normal individuals and to correlate amino acid codon length in CDR3 region with age and sex. RNA was isolated from PBLs of normal individuals and x chain was PCR amplified. Amino acid length of CDR3 region was determined by polyacrylamide gel electrophoresis. A low but constant expression of immunoglobulin x chain with 11 amino acid codons in CDR3 region in normal individuals was found (mean±SD=11.72±1.80%). Significant correlation was not found between amino acid length in CDR3 region of x chain and age or sex. These findings suggest that the concept that N-region addition in x light chain does not occur due to absence of terminal deoxynucleotidyl transferase (TdT) needs to be reconsidered. The existence of long CDR3 K chain in PBLs of normal individuals may reflect that CDR diversity in is quite common. Amino acid length of x chain CDR3 is not regulated during development and there is no influence of sex on the expression of x chain containing CDR3 with 11 amino acids.