Initial herpes simplex virus type 1 infection prevents ganglionic superinfection by other strains.

The ganglia of rabbits infected with a relatively benign strain of herpesvirus (E-43) and challenged with either of two virulent neurotrophic strains (MP or McKrae) were found to be colonized only by the initial benign infecting strain. Primary infection with the E-43 strain resulted in milder disease when the animals were infected with MP or McKrae strains and also prevented colonization of the ganglion by these strains. Neutralization with anti-glycoprotein C, plaque morphology, cytopathic effects, reconstruction experiments, and restriction endonuclease analysis indicated that the virus recovered from the ganglion was the initial infecting E-43 strain; no traces of the challenging MP and McKrae strains were found. The challenging McKrae strain was shed for several weeks in a few animals, but the virus isolated from the trigeminal ganglia of these animals was the primary infecting E-43 strain. These results suggest that initial infection with a relatively benign strain of herpesvirus may prevent superinfection of the ganglion (but not necessarily the end organ) by highly virulent herpes simplex virus strains and could have significant implications in the consideration of immunization against this disease in humans.