B Cells With Complementary B Cell Receptors Can Kill Each Other.

B cells differentiate from hematopoietic stem cells in the bone marrow (BM) and migrate as transitional cells to the spleen where final maturation takes place. Due to the enormous diversity in variable (V) regions of B cell receptors for antigen (BCR), B cells with complementary BCRs are likely to be generated. These could encounter each other in the BM or in secondary lymphoid organs.

De novo formation of early endosomes during Rab5-to-Rab7a transition.

Rab5 and Rab7a are the main determinants of early and late endosomes and are important regulators of endosomal progression. The transport from early endosomes to late endosome seems to be regulated through an endosomal maturation switch, where Rab5 is gradually exchanged by Rab7a on the same endosome. Here, we provide new insight into the mechanism of endosomal maturation, for which we have discovered a stepwise Rab5 detachment, sequentially regulated by Rab7a.

Real-time imaging of polymersome nanoparticles in zebrafish embryos engrafted with melanoma cancer cells: Localization, toxicity and treatment analysis.

Background: The developing zebrafish is an emerging tool in nanomedicine, allowing non-invasive live imaging of the whole animal at higher resolution than is possible in the more commonly used mouse models. In addition, several transgenic fish lines are available endowed with selected cell types expressing fluorescent proteins; this allows nanoparticles to be visualized together with host cells.

Methods: Here, we introduce the zebrafish neural tube as a robust injection site for cancer cells, excellently suited for high resolution imaging.

Receptor-Mediated Endocytosis of VEGF-A in Rat Liver Sinusoidal Endothelial Cells.

Background And Aims: Vascular endothelial growth factor (VEGF) receptors (VEGFR1 and VEGFR2) bind VEGF-A with high affinity. This study sought to determine the relative contributions of these two receptors to receptor-mediated endocytosis of VEGF-A and to clarify their endocytic itineraries in rat liver sinusoidal endothelial cells (LSECs).

Methods: Isolated LSECs and radiolabeled VEGF-A were used to examine surface binding and receptor-mediated endocytosis.

Tumor Killing by CD4 T Cells Is Mediated Induction of Inducible Nitric Oxide Synthase-Dependent Macrophage Cytotoxicity.

CD4 T cells can induce potent anti-tumor immune responses. Due to the lack of MHC class II expression in most cancer cells, antigen recognition occurs indirectly uptake and presentation on tumor-infiltrating antigen-presenting cells (APCs). Activation of the APCs can induce tumor rejection, but the mechanisms underlying tumor killing by such cells have not been established.