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.
All viruses must infect living cells to reproduce. HIV takes over certain immune system cells that are supposed to defend the body. These cells are called CD4 cells, or T cells. When HIV takes over a CD4 cell, it turns the cell into a virus factory. It forces the cell to produce thousands of copies of the virus.