The low-virulent African swine fever virus (ASFV/NH/P68) induces enhanced expression and production of relevant regulatory cytokines (IFNalpha, TNFalpha and IL12p40) on porcine macrophages in comparison to the highly virulent ASFV/L60.

The impact of infection by the low-virulent ASFV/NH/P68 (NHV) and the highly virulent ASFV/L60 (L60) isolates on porcine macrophages was assessed through the quantification of IFNalpha, TNFalpha, IL12p40, TGFbeta and ASFV genes by real-time PCR at 2, 4 and 6 h post-infection. Increased IFNalpha, TNFalpha and IL12p40 expression was found in infection with NHV, in which expression of TGFbeta was lower than in infection with L60. Principal component analysis showed a positive interaction of cytokines involved in cellular immune mechanisms, namely IFNalpha and IL12p40 in the NHV infection. Quantification by ELISA confirmed higher production of IFNalpha, TNFalpha and IL12p40 in the NHV-infected macrophages. Overall, our studies reinforce and clarify the effect of the NHV infection by targeting cellular and cellular-based immune responses relevant for pig survival against ASFV infection.