CUTTING EDGE - LIPOSOMAL FORMULATION OF A SELF LYMPHOMA ANTIGEN INDUCES POTENT PROTECTIVE ANTITUMOR IMMUNITY

We developed a liposome carrier for a model nonimmunogenic, self Ag. T his carrier reproducibly converted lymphoma Ig into a potent tumor rej ection Ag in mice, A single immunization induced protection against ch allenges representing 20 to 100 times the minimum lethal dose of paren tal tumor, This protective effect required minimal amounts of incorpor ated Ag and IL-2 and elicited specific Abs (compared with free Ag or l iposomal control Ig which did not elicit any specific Abs); depletion experiments demonstrated a requirement for effector CD4(+) and CD8(+) T cells, Head-to-head comparisons, indicating superior potency and ind uction of specific T cell activation, distinguished liposomal from pro totype, carrier-conjugated Ag. These results provide a strategy for fo rmulating weak tumor or other clinically important Ags into vaccines.