Amino acid substitutions in glycoprotein D mediate the ability of fusion from without-positive herpes simplex virus type 1 strains to penetrate at 4 degrees and in the presence of soluble glycoprotein D.

In former studies, we described herpes simplex virus type 1 (HSV-1) strains ANG, ANG path and HSZP as strains with special fusion activities, caused by mutations in the syn 3 locus. In this report, we describe the special penetration properties of these strains: their ability to penetrate at 4 degrees and to overcome the infection block caused by soluble glycoprotein D-1 (gD-1) in the medium. Using intertypic recombinants of HSV-1 strains ANG path and KOS, we showed that these penetration properties are the result of two mutations in amino acids 25 (Leu-Pro) and 27 (Gln-Arg) in the N-terminal part of the mature gD-1 glycoprotein.