Abstract
MHV CF antibody survey in ex-breeder mice from an infected colony were done with routine and anamnestic serology, and antibody detection rates were 37/279 (13%) and 141/277 (51%) respectively (Table 1) . In contrast, all of 2153 sera from other 4 non-infected colonies were shown to be negative by the anamnestic method (Table 2) . With mice from the infected colony significant anamnestic response was induced after injection with 0.1 ml of about 4 or more units CF antigen (Table 3) .