Comparison of viral phenotypes of 21 mother-child pairs.

(a)Isolates from corresponding mother-child pairs are indicated by the same number preceded by a letter: A for mothers and B for children. Time of sampling is indicated in parenthesis as months before (-), after (+) or within 1 week from (0) delivery/birth. Pairs were grouped according to the mother's virus phenotype, i.e. first those carrying an R5narrow, than an R5broad and last an R5X4 virus.Samples were used to infect U87.CD4 cells expressing wild type CCR5 or CXCR4, or one of the chimeric receptors FC-1, FC-2, FC-4b, FC-5, FC-6 or FC-7. Experiments were repeated twice. –, means no chimeric receptor is used.