African Swine Fever Virus Infection and Cytokine Response In Vivo: An Update

Abstract

African swine fever (ASF) is a hemorrhagic viral disease of domestic pigs and wild suids (all Sus scrofa) caused by the ASF virus (ASFV). The disease is spreading worldwide without control, threatening pig production due to the absence of licensed vaccine or commercially available treatments. A thorough understanding of the immunopathogenic mechanisms behind ASFV infection is required to better fight the disease. Cytokines are small, non-structural proteins, which play a crucial role in many aspects of the immune responses to viruses, including ASFV. Infection with virulent ASFV isolates often results in exacerbated immune responses, with increased levels of serum pro-inflammatory interleukins (IL-1α, IL-1β, IL-6), TNF and chemokines (CCL2, CCL5, CXCL10). Increased levels of IL-1, IL-6 and TNF are often detected in several tissues during acute ASFV infections and associated with lymphoid depletion, hemorrhages and oedemas. IL-1Ra is frequently released during ASFV infection to block further IL-1 activity, with its implication in ASFV immunopathology having been suggested. Increased levels of IFN-α and of the anti-inflammatory IL-10 seem to be negatively correlated with animal survival, whereas some correlation between virus-specific IFN-γ-producing cells and protection has been suggested in different studies where different vaccine candidates were tested, although future works should elucidate whether IFN-γ release by specific cell types is related to protection or disease development.

A Cell-Adapted Live-Attenuated Vaccine Protects Pigs against the Contemporary Pandemic African Swine Fever Virus

“…In this study, pigs vaccinated with VNUA-ASFV-LAVL2 possessed significantly higher number of ASFV-specific IFN-γ-producing cells than that in the non-vaccinated pigs. This observation is consistent with the previous reports [36][37][38].…”

“…Studies have speculated that cellular immune responses may play an important role in ASFV protective immunity. In particular, a T helper cell type 1 (Th1) immune response (producing IFN-γ) seems crucial in the establishment of a protective response against ASFV [36][37][38]. In this study, pigs vaccinated with VNUA-ASFV-LAVL2 possessed significantly higher number of ASFV-specific IFN-γ-producing cells than that in the non-vaccinated pigs.…”

Vaccines for African swine fever: an update

“…High levels of IL-10 suppressed the immune response to ASFV ( Sánchez-Cordón et al, 2020 ). As already mentioned above, evidence suggests that regulatory components of the immune system inhibit effective protection ( Franzoni et al, 2023 ).…”

Neglected Spleen Transcriptional Profile Reveals Inflammatory Disorder Conferred by Rabbit Hemorrhagic Disease Virus 2 Infection

“…Moreover, interleukins belong to a class of cytokines that have multiple effects and play critical immunomodulatory roles in recruiting immune cells to establish an inflammatory microenvironment. But high levels of cytokines and chemokines would trigger a “cytokines storm” that disrupted the balance between innate and adaptive immune responses [ 35 ]. Similar phenomena had been found in the impaired spleen by other RNA viruses [ 35 , 36 ].…”

“…But high levels of cytokines and chemokines would trigger a “cytokines storm” that disrupted the balance between innate and adaptive immune responses [ 35 ]. Similar phenomena had been found in the impaired spleen by other RNA viruses [ 35 , 36 ].…”