FURTHER EVIDENCE FOR THE RELATIONSHIP OF HIV-1 GP120 V3 LOOPS WITH IGSUPERFAMILY MEMBERS - SIMILARITY WITH THE PUTATIVE CDR3 REGION OF T-CELL RECEPTOR DELTA-CHAINS

Twenty-five V3 loops of envelope gp 120 extracted from 30 HIV-1 isolat es were compared with T-cell receptor (TCR) subunits variable (V) port ions using pairwise alignments of 11-residue peptides. The results ind icate that, in comparison with random sequences, the analyzed V3 loops , unlike control (unrelated) sequences, display highly significant loc al similarity with TCR V-delta (p approximate to 10(-20)). However, pa ttern-matching searches were performed on a much larger number of V3 l oops (484). In particular, selective pattern TR**NT*K*I is shared by V-delta from human T-cell line KT19E and 230 HIV-1 V3 loops (N-termina l portion). Pattern RAYT***I*G is common for V-delta chain isolated f rom T-cell line DS6 of an immunodeficient patient and 69 V3 loops (C-t erminal portion). The presented delta-chain portions of sequence simil arity with the V3 loops overlap the putative complementarity-determini ng region (CDR3), thus possibly indicating functional similarity too.