Tumor cells expressing anti-CD137 scFv induce a tumor-destructive environment.

For immunotherapy to become more effective, there is a need to maximize the antitumor response at the tumor site as well as to eliminate tumor cell variants that lack a given tumor antigen or the ability to present it. We have previously shown that wild-type (WT) cells from the K1735 melanoma (K1735-WT) are rejected following vaccination with cells (K1735-1D8) transfected to express scFv from the anti-CD137 monoclonal antibody 1D8, and that CD4(+) T cells and natural killer (NK) cells are needed for this rejection. We now show that tumors harvested 4 to 10 days after mice had been transplanted with K1735-1D8 cells or a mixture of K1735-1D8 and K1735-WT cells contained more NK cells and that they had an increased percentage of CD4(+) T lymphocytes producing IFNgamma or tumor necrosis factor-alpha.

Scanning electron microscopy of developing plant organs.

Shoot apices and young meristematic leaves can be examined directly with the scanning electron microscope without prior fixation or metal coating. The form of the shoot apex, cellular organization, andleaf arrangement (phyllotaxis) can be observed, perphaps as they have never been visualized before.

Proliferation of cells in the central cylinder of the reduced mutant in lanceolate tomato.

When the reduced phenotype in homozygous lanceolate tomato is cultured on a sterile nutrient medium, there is a considerable amount of cell division within the central cylinder. Such proliferation may occur in response to a stimulus furnished to the shoot by the root.