THE SIZES OF THE CDR3 HYPERVARIABLE REGIONS OF THE MURINE T-CELL RECEPTOR BETA-CHAINS VARY AS A FUNCTION OF THE RECOMBINED GERM-LINE SEGMENTS

A method using PCR amplification and primer extension with fluorescent oligonucleotides was developed to analyze T-cell repertoires. The siz es of the hypervariable CDR3-like regions of the murine T-cell antigen receptor beta chains were measured for all possible V(beta)-J(beta) c ombinations. This analysis shows that beta chains are distributed into at least 2000 groups, a value that provides a lower limit to their co mplexity. The CDR3 sizes appear to be dependent on the J(beta) and esp ecially the V(beta) segment used and correlates with amino acid sequen ce motifs in the corresponding CDR1 region. This feature of T-cell rec eptors is discussed.