Antigenic and protein sequence homology between VP13/14, a herpes simplex virus type 1 tegument protein, and gp10, a glycoprotein of equine herpesvirus 1 and 4.

Monospecific polyclonal antisera raised against VP13/14, a major tegument protein of herpes simplex virus type 1 cross-reacted with structural equine herpesvirus 1 and 4 proteins of Mr 120,000 and 123,000, respectively; these proteins are identical in molecular weight to the corresponding glycoprotein 10 (gp10) of each virus. Using a combination of immune precipitation and Western immunoblotting techniques, we confirmed that anti-VP13/14 and a monoclonal antibody to gp10 reacted with the same protein. Sequence analysis of a lambda gt11 insert of equine herpesvirus 1 gp10 identified an open reading frame in equine herpesvirus 4 with which it showed strong homology; this open reading frame also shared homology with gene UL47 of herpes simplex virus type 1 and gene 11 of varicella-zoster virus. This showed that, in addition to immunological cross-reactivity, VP13/14 and gp10 have protein sequence homology; it also allowed identification of VP13/14 as the gene product of UL47.