A reverse genetics approach to study feline infectious peritonitis

Area of Science:

• Veterinary Virology
• Immunopathology
• Molecular Biology

Background:

• Feline infectious peritonitis (FIP) is a severe, often fatal, immunopathological disease in domestic cats.
• Feline coronaviruses (FCoVs) are the causative agents of FIP, with type I and type II strains identified.
• Understanding the genetic basis of FCoV pathogenicity is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the pathogenicity of recombinant feline coronaviruses (FCoVs) using a reverse genetics approach.
• To assess the role of type I, type II, and chimeric type I/II FCoVs in inducing Feline infectious peritonitis (FIP).
• To identify genetic alterations in FCoV strains associated with FIP development.

Main Methods:

• Generation of recombinant type I, type II, and chimeric type I/II FCoVs via reverse genetics.
• Infection of cats with the generated recombinant FCoVs to assess pathogenicity.
• Sequence analysis of FCoV isolates from FIP-diseased cats to identify genetic mutations.

Main Results:

• All generated recombinant FCoVs successfully established productive infections in cats.
• Recombinant type II FCoV (strain 79-1146) was found to induce Feline infectious peritonitis (FIP).
• Sequence analysis revealed a critical mutation in the 3c gene stop codon of the FIP-inducing strain, restoring a full-length open reading frame (ORF).

Conclusions:

• Reverse genetics is a viable tool for studying FCoV pathogenicity and FIP.
• The type II FCoV strain 79-1146, with a restored 3c gene ORF, is capable of inducing FIP in cats.
• Genetic modifications, specifically in the 3c gene, play a significant role in the virulence of FCoVs and the pathogenesis of FIP.