| Popis: |
T cell activation has now been shown to require at least two signals. The first signal is antigen specific, is delivered through the T cell receptor via the peptide/MHC complex, and causes the T cell to enter the cell cycle. The second, or costimulatory, signal is required for cytokine production and proliferation, and is mediated through ligand interaction on the surface of the T cell. Several molecules normally found on the surface of professional antigen-presenting cells (APC) have been shown to be capable of providing the second signal critical for T cell activation. These molecules include B7–1 (CD80), B7–2 (CD86), intercellular adhesion molecule-1 (ICAM-1, CD54), and leukocyte function-associated antigen-3 (LFA-3, human CD58/murine CD48), among others. T cell costimulation has now been shown to be delivered via several modalities and delivery systems (i.e., recombinant retroviral vectors, recombinant poxviral vectors, and anti-CTLA-4 antibodies) to enhance anti-tumor immunity in experimental models. This chapter will deal principally with the use of recombinant poxvirus vectors to deliver an array of costimulatory molecules, via either direct vaccination approaches or whole-tumor-cell vaccines, to induce anti-tumor immunity. Both prevention and tumor-therapy models will be discussed. |
