The PCR product was ligated into the pCR II™ vector (TA cloning kit, Invitrogen Corporation, R&D Systems Europe Ltd, Abingdon, U.K.) and sequenced. Full length feline CD9 cDNAs were then amplified by PCR (as above) from cDNA prepared from the Mya-1 and MCC cell lines using primers H9-1+ and Poly A" and the products ligated in to the pCR II™ vector and sequenced