SLC7A1 and infection: The fluorescent syncytia were clearly detected in CC81-GREMG-CAT1 at 3 days post-cultivation, whereas fluorescent syncytia were detected in CC81-GREMG at 5 days post-cultivation (Fig. 3a and b), indicating that CC81-GREMG-CAT1 shows more rapid results with higher sensitivity for BLV cell-free infection than CC81-GREMG.