Most potential linear B cell epitopes of Env glycoproteins of feline immunodeficiency virus are immunogenically silent in infected cats.
A battery of sixty-six 20- to 23-amino acid synthetic peptides, partially overlapping by 10-12 amino acids, spanning the entire sequence of the envelope (Env) glycoproteins of the Petaluma isolate of feline immunodeficiency virus (FIV-Pet), has been used to map Env linear B cell epitopes. By screening FIV-infected cat sera for anti-peptide reactivity, the existence of two immunodominat domains, namely the V3 region of the surface (SU) glycoprotein and the domain including the highly conserved sequence QNQFF of the transmembrane (TM) glycoprotein, was detected; antibody-binding sites were also mapped in the domain overlapping the cleavage site between SU and TM encompassing the V6 variable region. Moreover, at least two novel linear B epitopes, the former spanning residues 427M-H446 and the latter spanning residues 737N-N756 and likely representing a "type-specific" determinant, have been revealed. The battery of synthetic peptides was then used to immunize outbred Swiss mice in the attempt to reveal other potential sites of immunogenicity of the Env glycoproteins. Analysis of peptide-immunized mouse sera for anti-peptide reactivity revealed more numerous B cell epitopes, generally mapping in different peptides, as compared with those defined in the feline system. None of the mouse anti-peptide sera, however, proved neutralizing for FIV-Pet.
Massi
C
C
Retrovirus Center, Department of Biomedicine, University of Pisa, Italy.
Lombardi
S
S
Indino
E
E
Matteucci
D
D
La Rosa
C
C
Esposito
F
F
Garzelli
C
C
Bendinelli
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D001665:Binding Sites; D002415:Cats; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology*; D015686:Gene Products, env / Q000276:immunology*; D015151:Immunoblotting; D051379:Mice; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000276:immunology
D000914:Antibodies, Viral; D000956:Antigens, Viral; D015686:Gene Products, env; D010446:Peptide Fragments