Abstract
Initially, we wanted to know whether dietary vitamin D3 restriction would influence growth and metastasis of the 4T1 murine mammary carcinoma. We confirmed serum 25(OH)D levels were modulated by dietary vitamin D3 restriction, mice were healthy, and when challenged with the 4T1 tumor alterations in tumor growth, but not metastasis were evident. Tumors grew more rapidly in mice on the vitamin D3 restricted diet. To delineate whether dietary vitamin D3 restriction influenced the ability to generate an antigen-specific immune response we used OTII transgenic mice which express a T cell receptor specific for ovalbumin. We found that dietary vitamin D3 restriction did not influence the health of OTII mice, the number of circulating CD3/CD4+, CD3/CD8+, CD4/CD25+ T cells, nor the ability to generate CD11c+ bone-marrow derived dendritic cells. T cells from OTII mice maintained on the vitamin D3 restricted diet also exhibited no significant alterations in proliferative capacity or ability to secrete IFN-γ or IL-4 in an antigen-specific manner. Yet, EL-4 tumors grew more rapidly in OTII mice on the vitamin D3 restricted diet. These data show that dietary vitamin D3 restriction impacts tumor growth, but not the ability to generate an antigen-specific immune response.