Quantitative evaluation of SLAM receptor-mediated enhancement in canine distemper virus detection: insights from viability, AUC, and MED analyses.

Canine distemper virus (CDV), a highly contagious member of the Morbillivirus genus in the Paramyxoviridae family, continues to threaten the health of domestic and wild carnivores worldwide. However, isolation of field strains is often limited by the low susceptibility of conventional cell lines lacking essential viral entry receptors. In this study, a recombinant Vero cell line stably expressing the canine signaling lymphocyte activation molecule (SLAM/CD150) receptor was established to improve CDV isolation efficiency. The SLAM gene was amplified from canine peripheral blood mononuclear cells (PBMCs), cloned into the pTargeT mammalian expression vector, and transfected into Vero cells. Functional expression of SLAM was validated by inoculation with a field isolate (CDV34388), which induced pronounced cytopathic effects and extensive syncytium formation in Vero-dogSLAM cells, whereas no syncytia were observed in non-transfected controls. Quantitative analyses revealed a mean 2.8-fold increase in minimum effective dilution (MED) values and an average area-under-the-curve (ΔAUC) of + 98 units in SLAM-expressing cells compared with normal Vero cells (p < 0.001), indicating markedly enhanced viral replication and cytopathic activity. These findings demonstrate that canine SLAM expression significantly improves CDV detection and isolation from field samples, establishing a robust in vitro model for future diagnostic and vaccine development studies.