A network of vessels, tissues, and organs in vertebrate animals that helps the body regulate fluid balance and fight against disease. The vessels of the lymphatic system drain excess fluid (called lymph) from the tissues and return it to the circulating blood. Lymphocytes circulate throughout the lymphatic system. A network of vessels that return lymph from body tissues to blood and filter out harmful particles on the way.
HIV infects cells in the central nervous system and the immune system. HIV's main target cell is the T helper lymphocyte. These cells play a crucial role in the immune system, by coordinating the actions of other immune system cells.A large reduction in the number of T helper cells seriously weakens the immune system.he Human Immunodeficiency Virus (HIV) seems to only infect the CD4 (or T-helper) cells of the immune system. The CD4 cells are responsible for activating and directing other â¦ immune system cells.
The macrophage is just one cell type that may present antigens in the MHCII complex; other cells, including B cells and dendritic cells, may also act as antigen-presenting cells (APC). Only a few helper T cells in the immune system will recognize the specific antigen presented by the APC.One helper T cell must become thousands of T cells to mount the immune response against the foreign invader. The animation illustrates the passage of signals through the cell that results in T-cell proliferation.he macrophage is just one cell type that may present antigens in the MHCII complex; other cells, including B cells and dendritic cells, may also act as antigen-presenting cells (APC). Only a few helper T cells in the immune system will recognize the specific antigen presented by the APC.