CD4(+) T cells regulate pulmonary metastasis of mammary carcinomas by enhancing protumor properties of macrophages.

During breast cancer development, increased presence of leukocytes in neoplastic stroma parallels disease progression; however, the functional significance of leukocytes in regulating protumor versus antitumor immunity in the breast remains poorly understood. Utilizing the MMTV-PyMT model of mammary carcinogenesis, we demonstrate that IL-4-expressing CD4(+) T lymphocytes indirectly promote invasion and subsequent metastasis of mammary adenocarcinomas by directly regulating the phenotype and effector function of tumor-associated CD11b(+)Gr1(-)F4/80(+) macrophages that in turn enhance metastasis through activation of epidermal growth factor receptor signaling in malignant mammary epithelial cells. Together, these data indicate that antitumor acquired immune programs can be usurped in protumor microenvironments and instead promote malignancy by engaging cellular components of the innate immune system functionally involved in regulating epithelial cell behavior.

Apolipophorin III lysine modification: Effect on structure and lipid binding.

Apolipophorin III (apoLp-III) from Locusta migratoria was used as a model to investigate apolipoprotein lipid binding interactions. ApoLp-III contains eight lysine residues, of which seven are located on one side of the protein. To investigate the role of positive charges on lipid binding, lysine residues were acetylated by acetic anhydride.

Tyrosine fluorescence analysis of apolipophorin III-lipopolysaccharide interaction.

Apolipophorin III (apoLp-III) is an exchangeable apolipoprotein that binds to lipopolysaccharides (LPS). Polyacrylamide gel electrophoresis analysis demonstrated that apoLp-III from Galleria mellonella associated with various truncated LPS variants, including lipid A. Subsequent binding studies were performed employing the intrinsic tyrosine fluorescence properties of apoLp-III, which is highly quenched in the unbound state.