DECAY-ACCELERATING FACTOR CD55 IS IDENTIFIED AS THE RECEPTOR FOR ECHOVIRUS-7 USING CELICS, A RAPID IMMUNE-FOCAL CLONING METHOD

Using an anti-receptor mAb that blocks the attachment of echovirus 7 a nd related viruses (echoviruses 13, 21, 29 and 33), we have isolated a complementary DNA clone that encodes the human decay-accelerating fac tor (CD55). Mouse cells transfected with the CD55 clone bind echovirus 7, and this binding is blocked by the anti-receptor mAb. The method u sed (CELICS) allows rapid and direct cloning of genes encoding cell su rface receptors. It is based on episomal replication and high efficien cy expression of complementary DNA clones in the vector pCDM8 in COS o r WOP cells, in conjunction with a sensitive immune-focal screen that uses antibody probes linked to beta-galactosidase. Receptor positive c ells were identified by a colour change and isolated individually usin g a micromanipulator, DNA extracted from a small number of cells was t hen cloned directly in Escherichia coli.