Effect of siRNA mediated suppression of signaling lymphocyte activation molecule on replication of peste des petits ruminants virus in vitro

Signaling lymphocyte activation molecule (SLAM) expression was inhibited in B95a cell line using siRNA and the effect of SLAM inhibition on peste des petits ruminants virus (PPRV) replication and infectivity titre was studied. SLAM suppression was assessed using real-time PCR and flow cytometry to confirm suppression at the m-RNA and protein levels, respectively. Three chemically synthesized siRNAs were transfected individually using oligofectamine into B95a cell line. This resulted in SLAM suppression from 48 to 454-folds, in comparison to the untransfected B95a cell line. When the SLAM suppressed B95a cell line was infected with PPRV, replication was reduced by 12–143-folds and virus titre was reduced from log10 1.09 to 2.28. siRNA 3 showed the most potent inhibition of SLAM expression both at m-RNA and protein levels. This also caused the maximum reduction of virus replication and virus titre. A 100-fold reduction in PPRV titres was seen in anti-SLAM antibody neutralized B95a cell line. This further confirms that SLAM is one of the (co) receptors for PPRV. However, the presence of other putative virus receptor(s) is/are not ruled out.