Effect of Toll Like Receptor Agonists on Adaptive Immune Response Generated Against Newcastle Disease Virus in Chicken

Patel MV, Chauhan HC, Chandel BS, Kumar P, Patel AC, Patel SS, Shrimali MD, Dadawala AI and Sharma KK (2020). Effect of Toll Like Receptor Agonists on Adaptive Immune Response Generated Against Newcastle Disease Virus in Chicken. Journal of Immunology Immunopathology, 22(2): 207–213.

The present study envisaged the kinetics of in vivo responses to the TLR4 ligand lipopolysaccharide (LPS) and the TLR9 ligand CpG-ODNs as vaccine stimulator in chickens. Chickens were immunized by killed Newcastle Disease (ND) vaccine with either, 10ug of Salmonella Gallinarum LPS and 10ug of CpG ODNs, or both in combination. NDV vaccine alone and no vaccination group were used as reference control and negative control, respectively. Sera were collected on day 7^th, 14^th, 21^st, 28^th and 35^th of post immunization and response was measured by titration of anti NDV IgM and IgY antibodies using indirect ELISA. The antibody titer of vaccine + Salmonella Gallinarum LPS was recorded on 7^th day and persisted by 35^th day. The 7^th day titer was equivalent to vaccine only at 14^th day. Anti-NDV IgM antibody formed plateau earlier i.e., on 28^th day than anti NDV IgY antibody i.e., on 35^th day. Likewise, vaccine + CpG ODNs group titer was significantly higher (P<0.05) than that from control groups on all post immunization days. Indifferent to LPS, highest titer of Anti NDV IgM and IgY were found on day 28^th and 35^th, respectively. It was also evident that a good number of antibodies when both LPS and CpG agonists have simultaneously been used. In conclusion, adjuvant mimicking, immunostimulatory effect of Salmonella Gallinarum LPS and CpG ODNs, either alone or in combination, produce an early titer of antibodies wh ich was maintained for at least 28 days. Hence these can be used to augment protective immune response of NDV vaccine.