RT Journal Article SR Electronic(1) A1 Lombardi, Stefania A1 Massi, Claudia A1 Tozzini, Franco A1 Zaccaro, Lucia A1 Bazzichi, Agostino A1 Bandecchi, Patrizia A1 La Rosa, Corinna A1 Bendinelli, Mauro A1 Garzelli, CarloYR 1995 T1 Epitope mapping of the V3 domain of feline immunodeficiency virus envelope glycoprotein by monoclonal antibodies JF Journal of General Virology, VO 76 IS 8 SP 1893 OP 1899 DO https://doi.org/10.1099/0022-1317-76-8-1893 PB Microbiology Society, SN 1465-2099, AB A panel of six IgG monoclonal antibodies (MAbs) was produced by immunizing mice with a 22 amino acid synthetic peptide, designated V3.3, of the third variable region of feline immunodeficiency virus (FIV) envelope glycoprotein. This peptide is known to induce neutralizing antibodies in cats. In ELISA all MAbs reacted with purified SDS-disrupted FIV and in flow cytometry all MAbs stained permeated, persistently infected FL4 cells but not unfixed FL4 cells; this indicated that the MAbs recognize essentially cryptic epitopes of the gp100 V3 loop. By direct ELISA using partially overlapping synthetic peptides and by competition binding studies, the anti-V3.3 MAbs were shown to detect at least four distinct epitopes, two located in the amino-terminal half and two in the carboxy-terminal half of the sequence. When tested for neutralizing activity by the syncytium inhibition assay in Crandell feline kidney cells, all anti-V3.3 MAbs neutralized FIV at high dilution. However, at low dilution two MAbs exhibited much less neutralizing activity. These results indicate that the V3 region of FIV contains multiple epitopes involved in neutralization., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-76-8-1893