Host Responses to Live-Attenuated ASFV (HLJ/18-7GD)

Viruses. 2022 Sep 10;14(9):2003. doi: 10.3390/v14092003.

Abstract

African swine fever (ASF) is a highly contagious and fatal disease caused by the African swine fever virus. Recently, the multigene family and CD2v gene-deleted ASF vaccine candidate HLJ/18-7GD was found to be safe and effective in laboratory and clinical trials. However, the immune-protective mechanisms underlying the effects of HLJ/18-7GD remain unclear. We assessed samples from pigs immunized with a single dose of 106 TCID50 HLJ/18-7GD. We found that pigs immunized with HLJ/18-7GD showed high levels of specific antibodies. T lymphocyte subsets (helper T cells (Th); cytotoxic T lymphocytes (CTL); double-positive T cells (DP-T cells)) were temporarily increased in peripheral blood mononuclear cells (PBMCs) after HLJ/18-7GD immunization. Once the HLJ/18-7GD-immunized pigs had been challenged with virulent HLJ/18, the percentage of Th, CTL, and DP-T cells increased significantly. PBMCs extracted from the pigs induced higher levels of CD8+ T cells after infection with the HLJ/18 strain in vitro. The levels of GM-CSF, IFN-γ, and TNF-α were upregulated at 7 days post-inoculation; this finding was contrary to the results obtained after HLJ/18 or HLJ/18ΔCD2v infection. The immune protection from HLJ/18-7GD resulted from many synergies, which could provide a theoretical basis for HLJ/18-7GD as a safe and effective ASF vaccine.

Keywords: ASF; HLJ/18-7GD strain; T cell; antibody; cytokine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • African Swine Fever Virus*
  • African Swine Fever*
  • Animals
  • CD8-Positive T-Lymphocytes
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • Leukocytes, Mononuclear
  • Swine
  • Tumor Necrosis Factor-alpha
  • Viral Proteins
  • Viral Vaccines*

Substances

  • Tumor Necrosis Factor-alpha
  • Viral Proteins
  • Viral Vaccines
  • Granulocyte-Macrophage Colony-Stimulating Factor

Grant support

This research and APC were funded by National Key R&D Program of China (Grant No. 2021YFD1801405) and the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (CAAS-ASTIP).