A DIRECTORY OF HUMAN GERM-LINE V-CHI SEGMENTS REVEALS A STRONG BIAS IN THEIR USAGE

From the genomic DNA of a single individual, we have amplified, cloned and sequenced 37 human germ-line V-kappa segments. Four of these segments were new. We then compiled a comprehensive directory of all germ-line V-kappa segments and identified 50 different sequences with open reading frames. Comparison with 236 rearranged sequences revealed that no more than 24 of these germ-line sequences could be assigned rearranged counterparts, that some of these were rarely used, and that only about 11 sequences are used frequently. This suggests that the expressed V-kappa repertoire is mainly derived from a limited number of segments. Most surprisingly, the J(kappa)-distal region of the locus appears to be rarely used: we could unambiguously assign 162 rearranged sequences to V-kappa segments of the J(kappa)-proximal region, but only 5 to segments of the J(kappa) -distal region.