ASFV activates STAT3 to induce proviral M2 macrophage polarization

Area of Science:

• Veterinary Virology
• Immunology
• Cell Biology

Background:

• African swine fever (ASF) is a highly infectious viral disease impacting the global pig industry.
• Macrophages are key targets of the African swine fever virus (ASFV), but their polarization during infection is unclear.

Purpose of the Study:

• To investigate macrophage phenotypic changes during ASFV infection.
• To elucidate the role of STAT3 in ASFV-induced macrophage polarization.
• To assess the impact of M2 polarization on viral replication and adaptive immunity.

Main Methods:

• Observation of peripheral blood monocytes in ASFV-infected pigs.
• In vitro macrophage polarization assays.
• STAT3 inhibition using STATTIC.
• Co-culture experiments with T cells (MLR system).

Main Results:

• ASFV infection increased M2 monocyte populations.
• ASFV induced M2 polarization via STAT3 phosphorylation.
• STAT3 inhibition blocked M2 polarization and suppressed ASFV replication.
• M2 macrophages showed reduced killing capacity and impaired T cell activation.

Conclusions:

• ASFV manipulates macrophage polarization to M2 phenotype through STAT3 signaling.
• M2 macrophages contribute to ASFV immune evasion and persistence.
• Targeting STAT3 may be a viable strategy for ASF control.