Vaccination protects against in vivo-grown feline immunodeficiency virus even in the absence of detectable neutralizing antibodies

Abstract

So far, vaccination experiments against feline immunodeficiency virus have used in vitro-grown virus to challenge the vaccinated hosts. In this study, cats were vaccinated with fixed feline immunodeficiency virusinfected cells and challenged with plasma obtained from cats infected with the homologous virus diluted to contain 10 cat 50% infectious doses. As judged by virus culture, PCRs, and serological analyses performed over an 18-month period after the challenge, all of the vaccinated cats were clearly protected. Interestingly, prior to challenge most vaccinees lacked antibodies capable of neutralizing a fresh isolate of the homologous virus.

FIV vaccine development and its importance to veterinary and human medicine: a review

“…e All the challenge strains are wild type without deletions. f Decreased FIV challenge load (5) but not against in vivo-derived challenges with heterologous FIV strains (Hesselink et al, 1999;Matteucci et al, 1996;Pu et al, 2001). Single-strain vaccines have only provided adequate protection against homologous and closely related strains but not against moderately to greatly heterologous FIV strains Elyar et al, 1997;Hesselink et al, 1999).…”

Effect of dual-subtype vaccine against feline immunodeficiency virus infection

“…In an SIV vaccine study, the protection observed in macaques immunized with SIV grown in human cells appears to be related more closely with an immune response directed to cell membrane antigens rather than a virus-specific immune response (Stott, 1991). However, in the FIV vaccine system, protection was reported to result from virus-specific immune responses and is not associated with immune responses against vaccine-derived cell membrane antigens Hosie et al, 1995;Matteucci et al, 1996). In this study also, antibodies against FeT-1 cell membrane antigens as well as virus-specific antibody were detected after vaccination (data not shown).…”

“…20 showing a neutralizing antibody titer < 1:10 was also protected against challenge with Petaluma virus. Studies have shown inconsistent results on the correlation between protection against FIV infection and the neutralizing antibody titer at the time of challenge Lombardi et al, 1994;Matteucci et al, 1996;Siebelink et al, 1995;Yamamoto et al, 1991b. Hosie and Flynn (1996) found that protection against challenge was correlated with the neutralizing antibody titer measured using a CrFK cell system but not with that measured in a NT assay based on the feline T cell line MBM.…”

“…A variety of vaccine approaches has been evaluated using the FIV model and these include fixed infected-cell, inactivated whole virus, subunit, and recombinant vaccines (Gonin et al, 1995;Hofmann-Lehmann et al, 1995;Hosie, 1994;Hosie and Flynn, 1996;Hosie et al, 1992Hosie et al, , 1995Lombardi et al, 1994;Lutz et al, 1995;Matteucci et al, 1996;Siebelink et al, 1995;Verschoor et al, 1995;Yamamoto et al, 1991bYamamoto et al, , 1993. Of these vaccine approaches, fixed infected cell and inactivated whole virus vaccines have successfully protected cats against homologous F1V challenge (Yamamoto et al, 1991b).…”

“…Furthermore, a similar preparation of inactivated whole virus vaccine was ineffective against FIV-UK-8 (FIVUK-8), a subtype A isolate which differed from FIVPet by 11% at Env amino acid sequence and in virus neutralization profile (Hosie et al, 1995). In a recent study, cats immunized with fixed FIV M2-infected MBM cells (IL-2-dependent feline T-lymphocyte line) were protected against homologous challenge with infected cat plasma (Matteucci et al, 1996). In another study, cats immunized three times with an inactivated whole virus vaccine retained vaccine-induced immunity for at least 8 months (Hosie et al, 1995).…”