Tropism determined by gene product of Herpes Simplex Virus is a natural barrier in mother-to-infant transmission

Mother-to-infant transmission of herpes simplex virus （HSV) is rare but has serious consequences. In two cases of paired HSV isolates from mother and infant, infantile isolates showed significantly better HepG2 hepatoblastoma cell-tropism and temperature adaptation in Vero cells than maternal isolates, and they had a mutation in common, which might have altered the characters of the infantile virus compared to the maternal virus. Generation of a mutation in the HSV infecting infants conferred altered cell tropisms, indicating that tropism acquisition by generation of the mutation for infecting viruses is a natural barrier to protect infants from mother-to-infant transmission of HSV