The immune system of chicken and its response to H9N2 avian influenza virus

Vet Q. 2023 Jun 26:1-25. doi: 10.1080/01652176.2023.2228360. Online ahead of print.ABSTRACTInfluenza A virus is a negative-sense single-stranded RNA virus that belongs to Orthomyxoviridae family. Based on the antigenic characteristics of hemagglutinin (HA) and neuraminidase (NA) influenza viruses are classified into subtypes. H9N2 belongs to the low pathogenic Avian Influenza Viruses (AIVs) and is one of the widely spread viruses in poultry, which can pose a threat to humans by directly infecting or providing internal genes for various zoonotic avian influenza strains. It may directly or indirectly participate in becoming an AIV that causes a human pandemic. When the virus enters a host, the innate immune system is activated first by pattern recognition receptors. The cytokines produced at the site of infection recruit innate immune cells and antigen-presenting cells and those cells subsequently transmit antigenic signals to adaptive immune cells (i.e., B cells and T cells), to trigger specific humoral and cellular immune responses. As a result, humoral and cellular immunity can clear virus and infected cells via antibody-mediated neutralization and cytotoxicity, respectively. Understanding how chicken immune systems respond to H9N2 is a top priority for effectively controlling the virus's spread and designing vaccines. In this review, we comprehensively discuss the role of the chicken immune system in defending against H9N2, and clarify the current limitations in understandi...
Source: Veterinary Quarterly - Category: Veterinary Research Authors: Source Type: research