They are essential in B cell antibody class switching, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages. Mature T h cells express the surface protein CD4 and are referred to as CD4+ T cells.Such CD4 + T cells are generally treated as having a pre-defined role as helper T cells within the immune system.hey are essential in B cell antibody class switching, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages. Mature T h cells express the surface protein CD4 and are referred to as CD4+ T cells.
To boil artichokes: 1  Fill a large stainless-steel or enameled pot with lightly salted water; bring to boiling. 2  Add artichokes and return water to boiling. 3  Reduce heat; simmer, covered, for about 20 to 30 minutes or until you can easily pull out a leaf from the center of an artichoke.
Bring the water, bay leaves, salt, and peppercorns to a boil in a large pot. With a small, sharp knife, trim the tough outer skin from the artichoke stems and remove the bottom row of leaves. Add the artichokes and lemons and return to a boil. Place 2 small, heavy plate on top of the artichokes, lower the heat, and cook at a low boil until the artichokes are tender, about 20 minutes. They are ready when you can pierce the bottom without resistance. Drain in a colander and let the artichokes sit until cool enough to handle.