Pathogenesis of oral type I feline infectious peritonitis virus (FIPV) infection: Antibody-dependent enhancement infection of cats with type I FIPV via the oral route

Abstract

Feline infectious peritonitis virus (FIPV) causes a severe, immune-mediated disease called FIP in domestic and wild cats. It is unclear whether FIP transmits from cat to cat through the oral route of FIPV infection, and the reason for this includes that FIP is caused by oral inoculation with some FIPV strains ( e.g. , type II FIPV WSU 79-1146), but is not caused by other FIPV ( e.g. , type I FIPV KU-2 strain: FIPV-I KU-2). In this study, when cats passively immunized with anti-FIPV-I KU-2 antibodies were orally inoculated with FIPV-I KU-2, FIP was caused at a 50% probability, i.e., FIPV not causing FIP through oral infection caused FIP by inducing antibody-dependent enhancement. Many strains of type I FIPV do not cause FIP by inoculation through the oral route in cats. Based on the findings of this study, type I FIPV which orally infected cats may cause FIP depending on the condition.

In Vivo Antiviral Effects of U18666A Against Type I Feline Infectious Peritonitis Virus

“…In U18666A-treated groups, the incidences of FIP were zero or suspected to be one of five cats. In a previous experiment, FIPV KU-2 caused FIP at a rate of 20%-40% by intraperitoneal inoculation [28,29]. On the bases on those facts, U18666A might have suppressed the development of FIP in FIPV-infected cats.…”

Is antibody-dependent enhancement playing a role in COVID-19 pathogenesis?

“…In vitro infection of macrophages by FIPV can be enhanced by non-neutralising monoclonal antibodies against the spike viral protein, and this phenomenon may occur even with highly diluted neutralising antibodies, whereas pretreatment with protein A prevents the enhancement [15]. In addition, as many as 50% of cats passively immunised with anti-FIPV antibodies develop peritonitis when challenged with the same FIPV serotype [16]. An attenuated virus vaccine is currently available in several countries for intranasal delivery, but its use is still deemed controversial by some experts, both in terms of safety and efficacy.…”

What Does Plant-Based Vaccine Technology Offer to the Fight against COVID-19?

“…Similarly, adenoviral vectors could be applied in this field [15]. Vaccines based on whole viruses are associated with concerns about antibody-dependent enhancement of viral infection, reactogenicity, and strain reversion to pathogenic forms, among other safety issues [16]. Therefore, the path for vaccine development will require a detailed characterization, not only in terms of efficacy but also safety [17].…”