Protection of guinea pigs against local and systemic foot-and-mouth disease after administration of synthetic lipid amine (Avridine) liposomes.

Injection of the synthetic lipid amine, Avridine, in the form of liposomes, protected guinea pigs against the development of lesions from foot-and-mouth disease virus (FMDV) inoculated intradermally into the rear footpads. The animals were protected against the development of vesicles at the inoculation site as well as the systemic spread of virus. Maximal protection was obtained after intracardial injection of 5-10 mg doses of liposomal Avridine. Lower doses yielded decreased protection. Subcutaneous or intraperitoneal routes of liposomal Avridine injection were ineffective. Protection was maximal 0-24 h after injection of liposomes. Ethanol and emulsion formulations of Avridine could induce protection when injected intracardially but had toxic side effects. Guinea pigs protected against the first FMDV inoculation by liposomal and ethanol formulations of Avridine continued to be protected against lesions after a second inoculation 15-45 days later. FMDV protective antibody titers of these animals ranged from a low of less than 1:10 to greater than 1:1000.