Feline Coronavirus and Alpha-Herpesvirus Infections: Innate Immune Response and Immune Escape Mechanisms

SIMPLE SUMMARY: Feline coronavirus (FCoV) and feline herpesvirus-1 (FeHV-1) can induce infections that are difficult to prevent and to treat due to the involvement of host genetic factors and immune mechanisms. These two viruses areimportant examples of viral immune evasion of the host’s innate immune response. The innate immune system provides an early form of host protection from infectious diseases without pre-exposure and plays an essential role in determining the outcome of viral infections. The mechanisms that the innate immune system utilizes to counteract infections are based on therecognition of a relatively limited set of molecular structures that are either products of microbes (virus, bacteria, fungi, parasites) or expressed by injured or dead host cells. This review provides a brief overview of the main mechanisms achieved by host’s innate immunity, focusing primarily on the immune escape mechanisms developed and carried out by FCoV and FeHV-1 during infection. ABSTRACT: Over time, feline viruses have acquired elaborateopportunistic properties, making their infections particularly difficult to prevent and treat. Feline coronavirus (FCoV) and feline herpesvirus-1 (FeHV-1), due to the involvement of host genetic factors and immune mechanisms in the development of the disease and more severe forms, are important examples of immune evasion of the host’s innate immune response by feline viruses.It is widely accepted that the innate immune system, which providesan initial universal form of the mammalian host protection from infectious diseases without pre-exposure, plays an essential role in determining the outcome of viral infection.The main components of this immune systembranchare represented by the internal sensors of the host cells that are able to perceive the presence of viral component, including nucleic acids, to start and trigger the production of first type interferon and to activate the cytotoxicity by Natural Killercells, often exploited by viruses for immune evasion.In this brief review, we providea general overview of the principal tools of innate immunity, focusing on the immunologic escape implemented byFCoVand FeHV-1 duringinfection.