A negative search of acute canine distemper virus infection in DogSLAM transgenic C57BL/6 mice

Abstract

Canine distemper is a highly contagious and immunosuppressive viral disease caused by canine distemper virus(CDV), an enveloped RNA virus of the family Paramyxoviridae. The susceptible host spectrum of CDV is broad andincludes all families of the order Carnivora. To accomplish the infection, CDV requires an expression of signaling lymphocyteactivation molecule (SLAM) functioning as a cellular receptor which generally presents in a variety of different lymphoid cellsubpopulations, including immature thymocytes, primary B cells, activated T cells, memory T cells, macrophages and maturedendritic cells. The distribution of SLAM-presenting cells is in accordance with the lymphotropism and immunosuppressionfollowing morbillivirus infection. In the present study, the C57BL/6 mice engrafted with dog-specific SLAM sequence(DogSLAM) were used. The weanling (3-week-old) transgenic offspring C57BL/6 mice were infected with CDV Snyder Hill(CDV-SH) strain via the intranasal (n=6), intracerebral (n=6) and intraperitoneal (n=5) routes. Clinical signs, hematology,histopathology, immunohistochemistry, virus isolation and RT-PCR were observed for two weeks post infection. Resultsshowed that CDV-SH-inoculated transgenic mice displayed mild-to-moderate congestion of various organs (brain, lung,spleen, kidney, lymph node, and adrenal gland). By means of immunohistochemistry, virus isolation and RT-PCR, CDV couldnot be detected. The evidence of CDV infection in this study could not be demonstrated in acute phase. Even though thetransgenic mouse is not a suitable animal model for CDV, or a longer incubation period is prerequisite, it needs to be clarifiedin a future study.

Keywords

• C57BL/6 mice
• Canine distemper virus
• SLAM
• Snyder Hill strain