The protective effect of the humoral immune response associated with the inactivated H9N2 vaccine will decrease the load of H9N2 infection and limited its replication out the respiratory and GIT tissues and thus decrease the lead of the virus inside the birds tissue and reduced the associated inflammatory mediators (TNF-α and INF-γ); the immunosuppressive effect of E.coli infection decreases the birds response to the virus infection and potentiates the losses from the co-infection process (10, 15, 18–20, 23, 31–33). The gene discussed is TNF; the disease is coinfection.