Cells Involved in Immunity
- White Blood Cells (Neutrophils and Macrophages)
- These are phagocytes that engulf and destroy antigens.
- They may also direct particles to specialized T-lymphocytes.
- Lymphocytes
- T-cells and B-cells are involved in immunity.
- B-lymphocytes are made in the bone marrow and released into the bloodstream.
- T-lymphocytes are made in the thymus gland.
- T-cells recognize specific antigens and provide immunity.
- B-cells secrete antibodies (immune globulins) that bind to and destroy pathogens.
Types of T-Cells
- Helper T-cells
- Produce cytokines to kill pathogens.
- Cooperate with B-cells to produce antibodies against pathogens.
- Cytotoxic T-cells (Killer T-cells)
- Destroy pathogens.
- Stimulated by chemicals to produce helper T-cells, which target and destroy pathogens.
- Suppressor T-cells (Regulatory T-cells)
- Terminate immune responses.
- Control the activity of other T-lymphocytes.
Effects of HIV on T-Cells
- HIV causes AIDS, which is a syndrome resulting from compromised immunity, not a disease in itself.
- HIV attacks T-helper cells, which are crucial for fighting infections.
- T-helper cells have CD4 receptors that HIV binds to, leading to their destruction.
- Without T-helper cells, killer T-cells cannot be properly stimulated to function.