Dual-subtype FIV vaccine protects cats against in vivo swarms of both homologous and heterologous subtype FIV isolates


    loading  Checking for direct PDF access through Ovid

Abstract

ObjectiveTo evaluate the immunogenicity and efficacy of an inactivated dual-subtype feline immunodeficiency virus (FIV) vaccine.DesignSpecific-pathogen-free cats were immunized with dual-subtype (subtype A FIVPet and subtype D FIVShi) vaccine and challenged with either in vivo- or in vitro-derived FIV inocula.MethodsDual-subtype vaccinated, single-subtype vaccinated, and placebo-immunized cats were challenged with in vivo-derived heterologous subtype B FIVBang [10–100 50% cat infectious doses (CID50)], in vivo-derived homologous FIVShi(50 CID50), and in vitro- and in vivo-derived homologous FIVPet(20–50 CID50). Dual-subtype vaccine immunogenicity and efficacy were evaluated and compared to single-subtype strain vaccines. FIV infection was determined using virus isolation and proviral PCR of peripheral blood mononuclear cells and lymphoid tissues.ResultsFour out of five dual-subtype vaccinated cats were protected against low-dose FIVBang (10 CID50) and subsequently against in vivo-derived FIVPet (50 CID50) challenge, whereas all placebo-immunized cats became infected. Furthermore, dual-subtype vaccine protected two out of five cats against high-dose FIVBang challenge (100 CID50) which infected seven out of eight single-subtype vaccinated cats. All dual-subtype vaccinated cats were protected against in vivo-derived FIVPet, but only one out of five single-subtype vaccinated cats were protected against in vivo-derived FIVPet. Dual-subtype vaccination induced broad-spectrum virus-neutralizing antibodies and FIV-specific interferon-γ responses along with elevated FIV-specific perforin mRNA levels, suggesting an increase in cytotoxic cell activities.ConclusionDual-subtype vaccinated cats developed broad-spectrum humoral and cellular immunity which protected cats against in vivo-derived inocula of homologous and heterologous FIV subtypes. Thus, multi-subtype antigen vaccines may be an effective strategy against AIDS viruses.

    loading  Loading Related Articles