Analysis of the genetic diversity and phylogenetic relationship of Italian isolates of feline immunodeficiency virus indicates a high prevalence and heterogeneity of subtype B.

Pistello, Mauro; Cammarota, G; Nicoletti, Elisa; Matteucci, Donatella; Curcio, M. Joan; Mauro, Daniela; Bendinelli, Mauro

doi:10.1099/0022-1317-78-9-2247

Cited by 56 publications

(54 citation statements)

References 31 publications

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“…Encouraging results have indicated that it is possible to protect cats against challenge with primary FIV isolates, depending on their regional distribution. By vaccinating cats with a whole inactivated vaccine based on the subtype B Pisa M2 strain, cats were protected from natural challenge with subtype B isolates of FIV (Pistello et al, 1997). It has been suggested that subtype B isolates may be more ancient and, accordingly, more host-adapted (Bachmann et al, 1997), hence they may be more readily neutralizable by the host humoral response.…”

Section: Introductionmentioning

confidence: 99%

Neutralization of feline immunodeficiency virus by antibodies targeting the V5 loop of Env

Samman

Logan

McMonagle

et al. 2009

Journal of General Virology

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Neutralizing antibodies (NAbs) play a vital role in vaccine-induced protection against infection with feline immunodeficiency virus (FIV). However, little is known about the appropriate presentation of neutralization epitopes in order to induce NAbs effectively; the majority of the antibodies that are induced are directed against non-neutralizing epitopes. Here, we demonstrate that a subtype B strain of FIV, designated NG4, escapes autologous NAbs, but may be rendered neutralization-sensitive following the insertion of two amino acids, KT, at positions 556-557 in the fifth hypervariable (V5) loop of the envelope glycoprotein. Consistent with the contribution of this motif to virus neutralization, an additional three subtype B strains retaining both residues at the same position were also neutralized by the NG4 serum, and serum from an unrelated cat (TOT1) targeted the same sequence in V5. Moreover, when the V5 loop of subtype B isolate KNG2, an isolate that was moderately resistant to neutralization by NG4 serum, was mutated to incorporate the KT motif, the virus was rendered sensitive to neutralization. These data suggest that, even in a polyclonal serum derived from FIV-infected cats following natural infection, the primary determinant of virus-neutralizing activity may be represented by a single, dominant epitope in V5. INTRODUCTIONFeline immunodeficiency virus (FIV) was first isolated in 1986 in Petaluma, CA, USA, from a cat with an immunodeficiency-like syndrome (Pedersen et al., 1987) and is an important pathogen of domestic cats worldwide. FIV is the feline homologue of human immunodeficiency virus (HIV) and these viruses share many biological and pathogenic features (Bendinelli et al., 1995;English et al., 1993;Johnson et al., 1994), typified by a selective targeting of CD4 + T lymphocytes and the induction of a progressive immunosuppression (Ackley et al., 1990).The induction of an effective humoral response against lentivirus infection is a key element in the immunological control of the disease, and the primary target for neutralizing antibodies (NAbs) is the virus envelope glycoprotein (Env) (Binley et al., 2004;Frost et al., 2005;Wei et al., 2003). Env varies by up to 30 % amongst FIV subtypes (Hosie & Beatty, 2007) and, thus, the preparation of an immunogen capable of inducing broadly neutralizing antibody responses against such diverse isolates of FIV would be of great value to the development of an FIV vaccine. Further, the development of a vaccine against FIV would have implications extending beyond veterinary medicine; FIV is the only non-primate lentivirus that induces AIDS-like symptoms in its natural host and, as such, is a valuable animal model for both prophylactic and therapeutic studies for HIV (Bendinelli et al., 1995;Elder et al., 1998;Okada et al., 1994). Moreover, cats have the advantage of being easier to breed and have shorter life cycles than other animal models currently used for HIV research (Miller et al., 2000).Previous studies showed that vaccination with whole inactivated va...

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Section: Introductionmentioning

confidence: 99%

Neutralization of feline immunodeficiency virus by antibodies targeting the V5 loop of Env

Samman

Logan

McMonagle

et al. 2009

Journal of General Virology

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“…Similar to HIV-1, FIV isolates have been grouped into different clades or subtypes (designated A to D) with different geographic distributions (2). For example, clade A FIV is prevalent in northern Europe and the United States, while clade B FIV is highly predominant in Italy (26).…”

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confidence: 99%

Immunogenicity of an Anti-Clade B Feline Immunodeficiency Fixed-Cell Virus Vaccine in Field Cats

Matteucci¹,

Poli

Mazzetti³

et al. 2000

J Virol

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Attempts at vaccine development for feline immunodeficiency virus (FIV) have been extensive, both because this is a significant health problem for cats and because FIV may be a useful vaccine model for human immunodeficiency virus. To date, only modest success, producing only short-term protection, has been achieved for vaccine trials in controlled laboratory settings. It is unclear how relevant such experiments are to prevention of natural infection. The current study used a vaccine that employs cell-associated FIV-M2 strain fixed with paraformaldehyde. Subject cats were in a private shelter where FIV was endemic, a prevalence of 29 to 58% over an 8-year observation period. Cats roamed freely from the shelter through the surrounding countryside but returned for food and shelter. After ensuring that cats were FIV negative, they were immunized using six doses of vaccine over a 16-month period and observed for 28 months after the initiation of immunization. Twenty-six cats (12 immunized and 14 nonimmunized controls) were monitored for a minimum of 22 months. Immunized cats did not experience significant adverse effects from immunization and developed both antibodies and cellular immunity to FIV, although individual responses varied greatly. At the conclusion of the study, 0 of 12 immunized cats had evidence of FIV infection, while 5 of 14 control cats were infected. Thus, the vaccine was safe and immunogenic and did not transmit infection. Furthermore, vaccinated cats did not develop FIV infection in a limited clinical trial over an extended time period. Thus, the data suggest that a fixed, FIV-infected cell vaccine has potential for preventing natural FIV infection in free-roaming cats.

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“…A number of FIV strains have been identified throughout the world, and their corresponding genomes have been partially sequenced (1,5,6,10,13,15,18,19,22,27,32). Studies developed on the basis of the nucleotide sequences from the envelope gene separated FIV strains into five distinct phylogenetic subtypes designated A to E (1, 2, 10, 13,22,27).…”

mentioning

confidence: 99%

“…Studies developed on the basis of the nucleotide sequences from the envelope gene separated FIV strains into five distinct phylogenetic subtypes designated A to E (1, 2, 10, 13,22,27). Although geographic isolation could be a major factor in the evolution of FIV, individual subtypes are found in more than one part of the world (1,2,5,13,19,27).…”

mentioning

confidence: 99%

Phylogenetic Analyses of Texas Isolates Indicate an Evolving Subtype of the Clade B Feline Immunodeficiency Viruses

Weaver¹,

Collisson²,

Slater

et al. 2004

J Virol

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Rigorous phylogenetic analyses were used to compare the nucleotide sequences of feline immunodeficiency virus strains isolated from Texas and throughout the world. The envelope V3-V4 sequences and capsid gene of the Texas isolates formed a cluster between subtypes B and E. Statistical comparisons with other published sequences confirmed that the Texas group is a unique cluster, possibly a new subtype, arising from subtype B.

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Analysis of the genetic diversity and phylogenetic relationship of Italian isolates of feline immunodeficiency virus indicates a high prevalence and heterogeneity of subtype B.

Cited by 56 publications

References 31 publications

Neutralization of feline immunodeficiency virus by antibodies targeting the V5 loop of Env

Neutralization of feline immunodeficiency virus by antibodies targeting the V5 loop of Env

Immunogenicity of an Anti-Clade B Feline Immunodeficiency Fixed-Cell Virus Vaccine in Field Cats

Phylogenetic Analyses of Texas Isolates Indicate an Evolving Subtype of the Clade B Feline Immunodeficiency Viruses

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