CYTOLYTIC ACTIVITY-INDUCED BY INTRAMUSCULAR INJECTION OF PLASMID DNA EXPRESSING THE NUCLEOCAPSID PROTEIN OF THE JHM STRAIN OF MOUSE HEPATITIS-VIRUS INTO C57BL 6 MICE/

We constructed plasmids expressing mRNA7 coding the nucleocapsid (N) p rotein of JHM strain of MHV (JHMV) under the control of Rous sarcoma v irus (RSV) LTR or human elongation factor (EF) la promoter, referred t o as pRSV-mRNA7 and pEF-mRNA7, respectively. Although only a slight le vel of cytolysis was observed by the spleen cells from C57BL/6 mice in jected intramuscularly with pEF-mRNA7, the spleen cells from the mice administered with pRSV-mRNA7 showed a significant level of cytolytic a ctivities against the cells expressing the viral N protein. The differ ence in the level of specific cytolysis might have been mainly due to a difference in the expression levels of the N protein in the muscles between the mice injected with pEF-mRNA7 and pRSV-mRNA7, since the spe cific activity of chloramphenicol acetyltransferase (CAT) in muscles f rom the mice injected with plasmid DNA expressing CAT gene directed by RSV LTR was significantly higher than that in those administered by t he plasmid DNA directed by EF-ia promoter.