Whereas gp350 orthologs are encoded in the majority of gammaherpesviruses, gp42 orthologs are present only in the genera Lymphocryptovirus, Percavirus and Macavirus. Infection of rabbits with C500 mutants unable to express A7 or A8 resulted in the absence of MCF development, with no hyperthermia and the absence of lymphadenopathy or splenomegaly, CD8+ T lymphocyte expansion and detectable viral genomes in lymphoid tissues. Here, CD8A is linked to Fever.