Pathogenicity and latency competence for rabbits of the herpes simplex virus type 1 ANGpath gC and gE defective mutants.

A total of 139 rabbits was infected to the right scarified cornea with HSV type 1 strains Kupka, ANG, ANGpath and their gE defective (ANGpathI2-4), gC defective (ANGpathgC18), gC/gE negative (ANGpathCI-8) and gC/ICP4 deletion (ANGpathY1) mutants. Strains ANG, ANGpath, ANGpathgC18 and ANGpathY1 were, in contrast to the two gE negative mutants, highly lethal, but 79% of rabbits infected with the non-encephalitogenic Kupka strain survived. Strain Kupka and strain ANGpath gE-negative mutants I2-4 and gCI-8 were tested for their latency competence. While Kupka established latency in the homolateral trigeminal ganglia from 80% of infected rabbits, I2-4 did so in one of 10 animals only, and the gC/gE mutant gCI-8 was not harboured in any of infected animals in an inducible form. Significant correlation was found between shedding into the culture fluid of reactivated virus from the explanted ganglion and brain stem fragments at one hand and the presence of the viral DNA in these organs on the other hand as judged by spot blot hybridization with the HSV-1 strain 17 Kpn I fragments h and i to DNA extracts prepared from these organs. Hybridizations were predominantly negative with the DNA from the corresponding non-cultured organs, except in a few cases of non-cultured ganglion and brain stem from rabbits previously infected with the gE deletion mutants which displayed positive hybridization, although no virus reactivation could be observed in corresponding explants.