Important note: Information in this article was accurate in 1988. The state of the art may have changed since the publication date.
CHARACTERIZATION OF NEUTRALIZING EPITOPES ON FELINE LEUKEMIA VIRUS USING MONOCLONAL AND ANTI-SYNTHETIC PEPTIDE ANTIBODIES,
Vaccines 87. Modern Approaches to New Vaccines: Prevention of AIDS and Other Viral, Bacterial, and Parasitic Diseases. Chanock RM et al, eds. New York, Cold Spring Harbor Laboratory, p. 263-7, 1987.. Unique Identifier : AIDSLINE ICDB/88647989 Elder JH; McGee J; Munson M; Houghten R; Bittle J; Grant C; Dept. of Molecular Biology, Res. Foundation of Scripps Clinic, La; Jolla, CA 92037
Abstract:
The feline leukemia viruses (FeLVs) are a polymorphic family of retroviruses found associated with malignant and degenerative diseases of the cat. Although animals infected with FeLV may eventually develop leukemias and lymphosarcomas, the most prevalent problem is an immunodeficiency syndrome, not unlike that associated with human acquired immune deficiency syndrome (AIDS). FeLV exhibits extensive polymorphism within the env gene encoding the surface glycoprotein, similar to other retroviruses, including the human immunodeficiency viruses (HIVs), and thus affords a system with the complexity one must address in developing a retrovirus vaccine. Two FeLV variants were analyzed that differ in their ability to be neutralized by a monoclonal antibody reactive at a common binding epitope. The study employed a monoclonal antibody (C11D8), prepared against intact virus, to map a neutralizing epitope. The monoclonal antibody reacted with I-26, 3B, and 13B1 but failed to react with 13B2, which lacked methionine at the amino terminus. The antibody bound to I-85 and I-87 but failed to bind to I-86, which differed from I-85 by the removal of a leucine residue at the carboxyl terminus. Several FeLV isolates were tested, including members of all three subtypes (termed A, B, and C), for neutralization by the monoclonal antibody. All but one of the isolates (B1) examined were neutralized. Nucleotide sequence analysis of the env gene was performed to determine the changes in gp70 that afford protection from neutralization by the monoclonal antibody. The minimal binding epitope required is the five-amino-acid sequence Met-Gly-Pro-Asn-Leu, which resides near the middle of the gp70 molecule. Protection was afforded by a single nucleotide change that resulted in the replacement of proline with leucine at a position three amino acids amino-terminal to the antibody-binding epitope. The data imply that this change alters the conformation of the binding epitope in the native structure, such that the affinity of the antibody for the epitope is dramatically reduced, resulting in failure to neutralize the virus. (5 Refs)
Keywords: Amino Acid Sequence Animal Antibodies, Monoclonal/*IMMUNOLOGY Antibodies, Viral/*IMMUNOLOGY Cats Epitopes/IMMUNOLOGY Glycoproteins/IMMUNOLOGY Leukemia Virus, Feline/*IMMUNOLOGY Neutralization Tests Peptides/*IMMUNOLOGY Vaccines, Synthetic/*IMMUNOLOGY Viral Envelope Proteins/*IMMUNOLOGY Viral Vaccines/*IMMUNOLOGY MEETING PAPER
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Important note: Information in this article was accurate in 1988. The state of the art may have changed since the publication date.
