CHARACTERIZATION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 P17 MATRIX PROTEIN MOTIFS ASSOCIATED WITH MOTHER-TO-CHILD TRANSMISSION

In order to determine if viral selection occurs during mother-to-child transmission of human immunodeficiency virus type I (HIV-1), we used a direct solid-phase sequencing method to sequence the p17 matrix prot ein-encoding regions of viral isolates from 12 HIV-1-infected mother-a nd-child pairs, 4 infected infants, 4 transmitting mothers, and 22 non transmitting mothers and compared the sequences, The blood samples wer e collected during the delivery period for the mothers and during the first month of life for most of the children, The p17 nucleic sequence s were distributed among several clades corresponding to the HIV-1 ci, B, and G subtypes, At the amino acid level, no significant difference s within the known p17 functional regions were observed among the subt ypes, Statistical analyses could be performed with the B subtype. With in the major p17 antibody binding site, a constant KIEEEQN motif (amin o acids 103 to 109) was Pound in all mother-and child isolates from th e B subtype. On the other hand, 9 of 17 nontransmitting mother isolate s were variable in this 103 to 109 region, Thus, this motif was signif icantly associated with the transmitting status (chi square, P = 0.003 4), A valine residue at position 103,vas significantly associated with the nontransmitting phenotype (chi square, P = 0.014), suggesting tha t it has a protective role during vertical transmission, The C-termina l end of p17 was globally conserved among nontransmitting mother isola tes (chi square, P = 0.0037), These results might improve the understa nding of the pathogenesis of HIV-1 vertical transmission and might all ow the screening of seropositive mothers by a rapid molecular or pepti de test.