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Adaptions of field PRRSVs in Marc-145 cells were determined by variations in the minor envelope proteins GP2a-GP3

Hong-Liang Zhang1, Yan-Dong Tang1, Chun-Xiao Liu1

  • 1State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.

Veterinary Microbiology
|August 7, 2018
PubMed

Insights

Porcine reproductive and respiratory syndrome viruses (PRRSVs) are evolving, with new strains adapting to infect cells differently. Research shows variations in minor envelope proteins (GP2a and GP3) determine PRRSV

Area of Science:

  • Virology
  • Molecular Biology
  • Animal Health

Background:

  • Porcine reproductive and respiratory syndrome viruses (PRRSVs) are rapidly evolving, leading to changes in their biological characteristics.
  • An increasing number of field PRRSVs are isolated from porcine alveolar macrophages (PAMs) but not from Marc-145 cells, indicating a shift in cell tropism.
  • Previous studies have identified PRRSV strains belonging to HP-PRRSV (lineage 8) or NADC30-Like (lineage 1) branches with distinct adaptive profiles.

Purpose of the Study:

  • To investigate the viral adaptation mechanisms of Marc-145-unadaptive field PRRSV strains.
  • To identify the genetic determinants responsible for PRRSV tropism in Marc-145 cells.
  • To explore the role of specific viral proteins in the adaptation of PRRSV to different cell types.

Main Methods:

  • Isolation and characterization of Marc-145-unadaptive PRRSV strains from PAMs.
  • Sequence analysis of isolated PRRSV strains to identify genetic variations, particularly in ORF2-4 regions.
  • Construction of a full-length cDNA clone of a representative Marc-145-unadaptive strain (MY-376).
  • Generation of serially chimeric viruses by exchanging genetic segments between an adaptive strain (HuN4-F112) and the unadaptive strain (MY-376).

Main Results:

  • Marc-145-unadaptive field PRRSV strains were successfully isolated from PAMs.
  • Sequence analysis revealed major variations in the ORF2-4 regions of these strains.
  • Chimeric virus experiments demonstrated that variations in the minor envelope protein (GP2a and GP3) complex are key determinants of PRRSV tropism for Marc-145 cells.

Conclusions:

  • The minor envelope proteins GP2a and GP3 play a critical role in determining the tropism of PRRSV for Marc-145 cells.
  • Understanding these viral adaptation mechanisms is crucial for controlling PRRSV spread and developing effective vaccines.
  • Further research into PRRSV evolution and adaptation can inform strategies to combat this economically significant swine disease.
Keywords:
GP2a and GP3MY-376Marc-145-unadaptiveTropismVariation

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