Showing papers by "Tak W. Mak published in 1994"

Transgenic mammals lacking expression of particular cd45 isoforms

Abstract: A mammal lacking expression of particular CD45 isoform in certain cells of the immune system is provided. The mammal may optionally contain a transgene encoding the CD45RO isoform. Also provided are methods of using these mammals.

Mammals lacking expression of cd28 transgenic

Abstract: Mammals lacking expression of CD28 or particular CD45 isoforms in certain cells of the immune system are provided. Also provided are methods of using these mammals.

Insights into the ontogeny and activation of T cells.

Abstract: T lymphocytes recognize antigen peptides and major histocompatibility complex products through their T-cell antigen receptors (TcR), consisting of alpha and beta chains. The interaction between T cells and their target cells or antigen-presenting cells is also assisted by a series of other cell-surface polypeptides, most notably CD4 and CD8, which are selectively expressed on mature helper/inducer and killer/suppressor T cells, respectively. Upon engagement of their ligands, a series of signals is transduced intracytoplasmically via some of these molecules and their associated proteins. Perhaps the most important enzyme in this signal transduction process is the lymphocyte-specific tyrosine kinase lck. Another important component is the cell-surface tyrosine phosphatase CD45. This molecule is alternatively spliced and the different isoforms are expressed on the various hematopoietic and lymphopoietic cells. Signaling through the TcR-CD4 D8-lck-CD45 complex is thought to be insufficient to activate T lymphocytes. A costimulatory signal is believed to be essential, and many investigators have suggested that CD28, a ligand for B7/BB1, is such a signal. Immune responses are also controlled by a number of cytokines and soluble factors. Signaling through the tumor necrosis factor receptor p55 is required for clearance of intracellular pathogens. Transcriptional factors involved in controlling interferon production are also important in T-cell development and immune responses. In an attempt to gain a better understanding of the roles of these molecules in T-lymphocyte functions and ontogeny, we generated a series of mutant mice with disruptions in the genes coding for these molecules. We are analyzing the mutant mice to evaluate the importance of these genes in T-cell development.

CD45 disrupted nucleic acid

Abstract: A mammal lacking expression of particular CD45 isoform in certain cells of the immune system is provided. The mammal may optionally contain a transgene encoding the CD45RO isoform. Also provided are methods of using these mammals.

Preparation and use of transgenic mice lacking expression of cd28

Abstract: Mammals lacking expression of CD28 or particular CD45 isoforms in certain cells of the immune system are provided. Also provided are methods of using these mammals.