Disclosed are immunologically active preparations of Herpes simplex virus envelope glycoproteins, gD-1 and gD-2. Preferably purified through use of a monoclonal anti-gD antibody immunoadsorbent, gD-1 and gD-2 preparations are incorporated in vaccines useful in generating immunological responses protective against Herpes simplex disease states. Disclosed also is the preparation and use in vaccination procedures of synthetic polypeptides comprising amino acid sequences which are: (1) substantially common to both gD-1 and gD-2; cumulatively hydrophilic in nature; and (3) specifically immunoreactive with a type common, monoclonal anti-gD antibody of Group VII classification.