the present invention provides variant hsv - 1 glycoprotein d and hsv - 2 glycoprotein d molecules capable of preventing infection of cells by herpes simplex virus types 1 and / or 2 . also provided are novel purified and isolated polynucleotides encoding the variant gd molecules . hsv gd - 1 and gd - 2 region iv variants or fragments thereof are specifically contemplated by the invention . the presently preferred variant molecule gd - 1 is the product of recombinant expression in sf9 cells of a fusion protein including the signal peptide of honeybee melittin and patton strain hsv - 1 gd wherein the patton strain amino acid residues 290 through 299 of the mature gd - 1 protein have been replaced with the amino acid residues arginine , lysine , isoleucine and phenylalanine , and patton strain amino acid residues 308 through 369 have been replaced with five histidine residues . when expressed in sf9 cells , cleavage of the melittin signal peptide results in the presence of aspartate and proline residues at the amino terminus of the variant molecule . the amino acid sequence of gd - 1 is set out in seq id no : 2 and the preferred dna sequence encoding gd - 1 is set out in seq id no : 1 . administration of gd variant molecules of the invention to mammalian subjects , especially humans , for the purpose of preventing hsv infection and / or ameliorating pathological sequelae of hsv infection is specifically contemplated .