Macrophages that have ingested foreign material carry some of the foreign antigen on their surface. The macrophages then carry the foreign cells to the T helper (Th) and T killer (Tk) cells in the lymph nodes, spleen and blood. The (as the name would suggest, help other cells of the Helper T-cells, Th immune system) recognise the non-self antigen (from the foreign cells) that the macrophages display on their outer surface. The Th recognise the antigens and stimulate B cells to proliferate - B cells will not reproduce and form plasma cells with out assistance from helper T cells. T helper cells also secrete proteins (interlukin and lymphokines) that stimulate other B and T cells to divide, where some of the cells become effector cells and memory T cells. Lymphokines stimulate macrophages to engulf invading cells. The interlukin can stimulate cytotoxic T cells (Tc) Cytotoxic (killer) T cells attacks body cells that have been infected by virus, bacteria or fungus. A Tc cell identifies its antigen, where in this case a viral protein coat is left outside the infected cell, and kills the infected cell before the virus has time to replicate. Tc cells kill the infected cells by secreting proteins (perforin) that punch holes in the membrane of the cell, and the contents ooze out. Tc cells cannot kill isolated virus particles, as they need the viral antigen before they become activated. Natural killer (Nk) cells have the same response as Tc cells, however they may attack tumor and other cancerous cells. Once the Th and Tc cells are activated, they divide many times, where some of the cells become effector T cells, and others as memory cells, where they migrate to the lymph nodes to be activated quickly upon a second invasion. Another type of T-cells is the T-suppressor cells, Ts These play an important role in regulating that – action of the lymphocytes, where they can help prevent the immune system overreacting to a stimulus. When the B and T cells develop in the bone marrow and thymus (respectively), they enter the blood stream, then leave it, and move around the body in the lymphatic system.
Macrophages that have ingested foreign material carry some of the foreign antigen on their surface. The macrophages then carry the foreign cells to the T helper (Th) and T killer (Tk) cells in the lymph nodes, spleen and blood. The Helper T-cells, Th (as the name would suggest, help other cells of the immune system) recognise the non-self antigen (from the foreign cells) that the macrophages display on their outer surface. The Th recognise the antigens and stimulate B cells to proliferate - B cells will not reproduce and form plasma cells with out assistance from helper T cells. T helper cells also secrete proteins (interlukin and lymphokines) that stimulate other B and T cells to divide, where some of the cells become effector cells and memory T cells. Lymphokines stimulate macrophages to engulf invading cells. The interlukin can stimulate cytotoxic T cells (Tc) Cytotoxic (killer) T cells attacks body cells that have been infected by virus, bacteria or fungus. A Tc cell identifies its antigen, where in this case a viral protein coat is left outside the infected cell, and kills the infected cell before the virus has time to replicate. Tc cells kill the infected cells by secreting proteins (perforin) that punch holes in the membrane of the cell, and the contents ooze out. Tc cells cannot kill isolated virus particles, as they need the viral antigen before they become activated. Natural killer (Nk) cells have the same response as Tc cells, however they may attack tumor and other cancerous cells. Once the Th and Tc cells are activated, they divide many times, where some of the cells become effector T cells, and others as memory cells, where they migrate to the lymph nodes to be activated quickly upon a second invasion. Another type of T-cells is the T-suppressor cells, Ts – These play an important role in regulating that action of the lymphocytes, where they can help prevent the immune system overreacting to a stimulus. When the B and T cells develop in the bone marrow and thymus (respectively), they enter the blood stream, then leave it, and move around the body in the lymphatic system.