A novel CCR5 mutation selectively affects immunoreactivity and fusogenic property of the HIV co-receptor.

A Nepalese heterozygous carrier of a CCR5 mutant, designated 118delF, was characterized. There was a 3 basepair deletion at 352-354 in the CCR5 open reading frame, resulting in the deletion of the phe-118 residue located in the third transmembrane domain. The mutant protein has retained antigen specificity near the third extra-cellular loop (ECL3), but that of ECL2 is markedly reduced. The mutation has also abrogated HIV co-receptor activity. Clinically, the HIV disease had progressed slowly.