The presumed natural route of MHV68 infection is through the upper respiratory tract [30] , whereupon the virus undergoes lytic replication in the mucosal epithelial cells lining the mouse lung and nasal cavity. Following intranasal inoculation, viral loads in the lung peak 5-8 dpi before subsiding as the virus traffics to the draining lymph nodes and ultimately to the spleen [31] . A burst of lytic replication occurs in these sites of latency establishment [30, 32] which seeds subsequent latency, primarily in germinal center B cells, although also in macrophages and dendritic cells [33] . By 14-18 dpi splenomegaly develops, and as many as one out of 100 splenocytes harbor the latent viral genome [34] .