Seroimmunotyping of African swine fever virus

Abstract

The extreme genetic and immunobiological heterogeneity exhibited by the African swine fever virus (ASFV) has been a significant impediment in the development of an efficacious vaccine against this disease. Consequently, the lack of internationally accepted protocols for the laboratory evaluation of candidate vaccines has become a major concern within the scientific community. The formulation of such protocols necessitates the establishment of a consensus at the international level on methods for the determination of homologous and heterologous isolates/strains of ASFV. The present article provides a comprehensive description of biological techniques employed in the classification of ASFV by seroimmunotypes. These techniques involve a holistic evaluation of ASFV isolates/strains based on their antigenic properties as determined by the hemadsorption inhibiting test (HAdI) using type-specific sera and an immunological test (IT) conducted on pigs inoculated with attenuated strains. The article outlines the methods for setting up the HAdI test, an IT on pigs, and the processes involved in the acquisition of type-specific serums for the HAdI test. It is pertinent to note that the definitive classification of seroimmunotype can only be ascertained after conducting an IT on pigs. The findings from the HAdI test or the phylogenetic analysis of the EP402R gene should be considered preliminary in nature.

Administration Routes and Doses of the Attenuated African Swine Fever Virus Strain PSA-1NH Influence Cross-Protection of Pigs against Heterologous Challenge

“…Both genotype I and genotype II ASFVs were found in pigs in China in 2021 [33]. The origin of the two detected nonhemadsorbing genotype I ASFVs, HeN/ZZZ-P1/21 and SD/DY-I/21, would become clearer after obtaining results about their immunotype in an in vivo immunologic test [16]. Some non-hemadsorbing natural isolates and laboratory recombinants have shown the ability to provide heterologous protection [23,24].…”

“…Preparation of peripheral blood leukocytes cell (PBLC) culture was performed as described previously [16].…”

“…Although ASFV genotyping is useful for some purposes, it does not fully correlate with the available data on cross-protection and may have limited value for predicting the effectiveness of vaccine cross-protection [12,13]. Based on the results of studying the antigenic and protective properties of isolates/strains, a seroimmunotype classification of ASFV was developed [14][15][16]. The isolates/strains of ASFV are divided into nine (I-IX) seroimmunotypes and three other small groups [15].…”

“…Based on the results of studying the antigenic and protective properties of isolates/strains, a seroimmunotype classification of ASFV was developed [14][15][16]. The isolates/strains of ASFV are divided into nine (I-IX) seroimmunotypes and three other small groups [15]. In 2015, a new approach was proposed, making it possible to predict with a high degree of probability the seroimmunotype/immunotype belonging to both hemadsorbing and non-hemadsorbing isolates of ASFV.…”

Genetic Variations of African Swine Fever Virus: Major Challenges and Prospects

“…This is because the replication mechanism of RNA viruses is more prone to errors, thereby increasing the opportunities for genetic variation and recombination. Additionally, the high genetic diversity in RNA viruses makes them more adaptable to environmental changes through mechanisms like recombination, enabling them to evade the host's immune response more effectively [29]. The discovery of recombination in ASFV provides substantial theoretical support for the study of recombination in DNA viruses, suggesting that DNA viruses, like RNA viruses, can exhibit high rates of recombination.…”