Heterologous response of antiserum-treated cell clones from a persistently infected DBT cell line to mouse hepatitis virus.

From DBT cells persistently infected with mouse hepatitis virus JHM strain (JHM-CC), a cell line producing neither infectious virus nor intracellular viral antigen was obtained after two passages in the presence of antiserum. In addition, 11 cell clones were manipulated from JHM-CC and found to be also free from the virus. These newly obtained cell line and 4 of 11 cell clones were shown to be resistant to JHM and the virus recovered from JHM-CC (JHM-CCV), while the other 7 cell clones were susceptible to both JHM and JHM-CCV as well as vesicular stomatitis virus. The susceptibility of all the cell clones and the newly obtained cell line to JHM and JHM-CCV became higher with passages. The observations were discussed in relation to the viral persistency in JHM-CC.