DEFINITION AND DISTRIBUTION ANALYSIS OF GLYCOPROTEIN-B GENE ALLELES OF HUMAN-HERPESVIRUS-7

As for other herpesviruses, glycoprotein B (gB) of human herpesvirus 7 (HHV-7) is believed to play a major role in virus infection and as a target of the host immunogenic response. Using nested PCR, we amplifie d the whole HHV-7 gB gene from 108 human peripheral blood mononuclear cell samples and studied its variability. By means of restriction frag ment length polymorphism (RFLP) analysis, three distinct patterns, des ignated I, II, and III, were defined and detected at frequencies of 93 , 5, and 2%, respectively, Determination of the nucleotide sequence al lowed us to recognize five critical positions in the gB gene with six specific combinations of point changes at these positions. These combi nations were gB alleles A, B, C, D, E, and F, Alleles D and E correspo nded to RFLP patterns II and III, respectively, while the other four a lleles corresponded to RFLP pattern I. Identical gB alleles were detec ted in serial samples as well as in paired samples of blood and saliva from the same individuals, except for one case. In contrast, the dist ribution of gB alleles differed according to the geographical origin o f the human samples: C was the most frequent allele in both African an d Caribbean samples, whereas F was the most frequent allele in Europea n ones. Although none of the allele-specific nucleotide changes induce d any modification at the protein level, the definition of gB alleles provided convenient viral markers for the study of both HHV-7 infectio ns and human population genetics.