AUTOLOGOUS RED-CELL AGGLUTINATION-TEST FOR ANTIBODIES TO FELINE IMMUNODEFICIENCY VIRUS

The T-lymphotropic lentivirus, feline immunodeficiency virus (FIV) is now recognised as a major viral pathogen affecting domestic cat popula tions worldwide. A rapid, autologous red cell agglutination test for a ntibodies to FIV has been developed. A synthetic peptide analog corres ponding to the immunodominant epitope within the FIV transmembrane gly coprotein gp40 residues (680-715) KVEAMEKFLYTAFAMQELGC (Acm)NQNQFFK(Br Ac) KTPLELWTR was conjugated to an anti-feline erythrocyte antibody us ing a thio-ether linkage. Within 3 min of adding this reagent to 20 mu l of whole blood, circulating antibody to the peptide epitope caused agglutination of the red blood cells. The performance of this simple t est is comparable with the two commercially available enzyme immunoass ay (EIA) kits and an EIA based on this peptide. A variant of the gp40 (680-715) peptide corresponding to the FIV, PPR strain gp40 (678-716) sequence was also synthesised and no difference in reactivity was obse rved in an EIA on 211 sero-positive samples, indicating that the pepti de-based test may be applicable to other known strains of the virus.