Mucosal immunization with experimental feline immunodeficiency virus (FIV)vaccines induces both antibody and T cell responses but does not protect against rectal FIV challenge

Feline immunodeficiency virus (FIV) is a natural lentiviral pathogen of cat s which can be experimentally transmitted via rectal and vaginal routes - t he major routes of human immunodeficiency virus type 1 transmission in man. An important objective for lentiviral research is the development of vacci ne strategies which generate good mucosal immune responses capable of givin g protection from a mucosal virus challenge. The experimental vaccines empl oyed in this study were based on (a) a peptide from the third variable regi on of the FIV envelope glycoprotein and (b) fixed whole FIV, Glasgow-8 stra in. Adjuvants used were Quil A and cholera toxin for mucosal administration and incomplete Freund's adjuvant and immune stimulating complexes for subc utaneous injection. Mucosal immunization was given by rectal and intranasal routes, Both antibody and proliferative responses were elicited by mucosal immunization and cholera toxin was found to be a good mucosal adjuvant. Th e addition of a lipo thioester to the FIV peptide improved IgG and IgA resp onses upon parenteral administration. However, no protection from a rectal FIV challenge was achieved. (C) 2000 Elsevier Science Ltd. All rights reser ved.