| Popis: |
T-lymphocytes are integral in the generation of virtually all the effector functions of the vertebrate immune response. They can be divided broadly into two populations based on the surface expression of either the CD4 or CD8 glycoprotein (Littman 1987). Even though both groups can be subdivided further based on the differential expression of other cell surface proteins and their ability to secrete different lymphokines (Mossman and Coffman 1987), the CD4-positive cells are a useful demarcation because they regulate a variety of different cell types. They secrete a variety of T-cell growth factors, principally interleukin 2 (IL-2), which are required for the expansion of both CD4 and CD8 cells. In addition, they support the induction of immunoglobulin synthesis by B cells (Howard and Paul 1983) and influence macrophage activation (Unanue 1984). Consequently in order logically to modulate the immune response of an individual, the proteins and the particular determinants involved in the generation of the T-cell response must be defined. Even though protective immunity can be generated without this understanding it is required both to improve the efficacy and to reduce harmful side effects of vaccination. |
