TY - JOUR
T1 - Comparison of CDR3 length among thymocyte subpopulations
T2 - Impacts of MHC and BV segment on the CDR3 shortening
AU - Matsutani, Takaji
AU - Ohmori, Takehiko
AU - Ogata, Masaki
AU - Soga, Hiroyuki
AU - Kasahara, Shigeru
AU - Yoshioka, Takeshi
AU - Suzuki, Ryuji
AU - Itoh, Tsunetoshi
N1 - Funding Information:
This work was supported in part by a grant-in aid for scientific research from the Ministry of Education, Science and Culture, Japan (16390045 to T.I. and 16590132 to T.M.).
PY - 2007/3
Y1 - 2007/3
N2 - Thymocytes are thought to be selected on the basis of antigen specificity between TCR and peptide-MHC (pMHC) ligands. The specificity depends primarily on extensive diversities of complementarity determining region 3 (CDR3), whose specificity is considered to be determined through thymocyte selection. We examined the CDR3 length profiles with 20 BV segments in thymocyte subpopulations from C57BL/6 (H-2b), C.B10 (Balb/c congenic, H-2b) and Balb/c (H-2d) mice. The CDR3 length was shorter in both CD4 single positive (SP) and CD8SP than in double positive (DP), but not altered among DP, double negative (DN) 4 and DN3 subpopulations. The CDR3 shortened more prominently in CD4SP than in CD8SP for C57BL/6 and C.B10, but the shortening was only slight for Balb/c. Although the shortening varied considerably among different BV segments, the greater shortening was observed in most BV segments for CD4SP and in several for CD8SP, in particular, the extent was the greatest in BV1, BV2, BV15, BV16, BV23 and BV26 for CD4SP, and in BV13-1 and BV29 for CD8SP. Moreover, the extent and the pattern of CDR3 shortening were basically the same among highly homologous BV segments (e.g. BV12-1 and 12-2; BV13-1, 13-2 and 13-3). These results taken together indicate that (1) the CDR3 shortening occurred between the DP to the SP stages but never earlier, that (2) there would be the MHC class preference for the CDR3 shortening, that (3) it was in part influenced by MHC haplotype, and finally that (4) the primary structure of particular BV segments would possibly affect the CDR3 length in selected thymocytes. It could be deduced from these results that the CDR3 shortening might play roles in ensuring geometrical disposition of CDRs unique to each BV segment and consequently allow CDRs to intimately interact with pMHC ligands.
AB - Thymocytes are thought to be selected on the basis of antigen specificity between TCR and peptide-MHC (pMHC) ligands. The specificity depends primarily on extensive diversities of complementarity determining region 3 (CDR3), whose specificity is considered to be determined through thymocyte selection. We examined the CDR3 length profiles with 20 BV segments in thymocyte subpopulations from C57BL/6 (H-2b), C.B10 (Balb/c congenic, H-2b) and Balb/c (H-2d) mice. The CDR3 length was shorter in both CD4 single positive (SP) and CD8SP than in double positive (DP), but not altered among DP, double negative (DN) 4 and DN3 subpopulations. The CDR3 shortened more prominently in CD4SP than in CD8SP for C57BL/6 and C.B10, but the shortening was only slight for Balb/c. Although the shortening varied considerably among different BV segments, the greater shortening was observed in most BV segments for CD4SP and in several for CD8SP, in particular, the extent was the greatest in BV1, BV2, BV15, BV16, BV23 and BV26 for CD4SP, and in BV13-1 and BV29 for CD8SP. Moreover, the extent and the pattern of CDR3 shortening were basically the same among highly homologous BV segments (e.g. BV12-1 and 12-2; BV13-1, 13-2 and 13-3). These results taken together indicate that (1) the CDR3 shortening occurred between the DP to the SP stages but never earlier, that (2) there would be the MHC class preference for the CDR3 shortening, that (3) it was in part influenced by MHC haplotype, and finally that (4) the primary structure of particular BV segments would possibly affect the CDR3 length in selected thymocytes. It could be deduced from these results that the CDR3 shortening might play roles in ensuring geometrical disposition of CDRs unique to each BV segment and consequently allow CDRs to intimately interact with pMHC ligands.
KW - Repertoire development
KW - T cells
KW - T-cell receptors
KW - Thymus
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U2 - 10.1016/j.molimm.2006.10.026
DO - 10.1016/j.molimm.2006.10.026
M3 - Article
C2 - 17156844
AN - SCOPUS:33846186870
VL - 44
SP - 2378
EP - 2387
JO - Immunochemistry
JF - Immunochemistry
SN - 0161-5890
IS - 9
ER -