IL1B and infection: As shown in Fig. 4, production of most cytokines resulting from SD16-MA infections was lower than that of SD16 virus (P<0.05); IL-1β and IL-5 levels in lungs of mice infected with SD16 and SD16-MA were similar (P>0.05); while the levels of IL-10 and IFN-γ in lung homogenates of mice inoculated with SD16-MA were higher than those of SD16 infected mice (P<0.05).