CD46 EXPRESSION DOES NOT OVERCOME THE INTRACELLULAR BLOCK OF MEASLES-VIRUS REPLICATION IN TRANSGENIC RATS

The study of measles pathogenesis and the testing of improved vaccine candidates is hampered by the lack of a small animal model which is su sceptible to infection by the intranasal route. With the identificatio n of CD46 as a measles virus (MV) receptor, it was feasible to generat e transgenic rats to overcome this problem. Although there was widespr ead expression of CD46 in the transgenic Sprague-Dawley rats, no measl es-like disease could be induced after various routes of infection. Th e expressed transgenic protein was functionally intact since it mediat ed MV fusion and was downregulated by contact with MV hemagglutinin. I n vitro studies revealed that CD46-expressing rat fibroblasts take up MV but do not allow viral replication, which explains the nonpermissiv eness of the transgenic rats for in vivo infection.