Form of antigen dictates immunity: Irradiated cell vs. whole cell lysate vaccination (48.16)

Abstract

Abstract The context in which antigen is perceived by the immune system dictates the quality of the ensuing immune response, which can range from tolerance to lasting immunity. In the current report we investigated the effects of vaccinating mice with antigen in two separate contexts, namely: Irradiated cells, or whole cell lysates. Using the MethA tumor model we observed that although a single vaccination with irradiated MethA cells leads to immunity in BALB/c mice, vaccination with the same cell equivalents of whole cell lysate does not. These results were surprising in light of the substantial body of literature demonstrating the immunostimulatory effects of cell lysates. We hypothesize that although each vaccination contains the same potential antigens, due to the different context in which they are delivered, the immune system will react to them differently. To test this we analyzed multiple characteristics of the immune response following vaccination with irradiated cells or whole cell lysates including: Tumor protection, the quantity and quality of an antigen specific T cell response, stability and persistence of antigen, and the effects of multiple vaccinations. We report dramatic differences between the two immunogens at each of the aspects tested. Our data suggests that although whole cell lysates contain antigen and the same potentially immunostimulatory components as irradiated cells, vaccinating mice with irradiated tumor cells leads to a much greater T cell response and tumor protection than does vaccinating with whole cell lysates.