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 extracellular 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.