Immunomodulatory Properties of Morbillivirus Nucleoproteins

Morbillivirus infections have been known for a long time to be associated with an acute immunosuppression in their natural hosts. Here, we show that recombinant Morbillivirus nucleoproteins from canine distemper virus, peste-des-petits-ruminants virus, and Rinderpest virus bind B-lymphocytes from dogs, goats, and cattle, respectively, similarly to measles virus nucleoprotein in humans. The use of surface plasmon resonance imaging allowed the real time detection of differential interactions between Morbillivirus nucleoproteins and FcgammaRIIb (CD32). Moreover, those nucleoproteins which bind murine Fcgamma receptor inhibited the inflammatory immune responses in mice in a Fc receptor- dependent manner. In contrast, nucleoprotein from closely related Henipavirus genus, belonging to the Paramyxoviridae family as Morbillivirus, was devoid of capacity either to bind FcgammaRIIb or to inhibit inflammatory response. Altogether, these results suggest that nucleoprotein-FcR interaction is a common mechanism used by different Morbilliviruses to modulate the immune response.