B2 [ U ] a situation in which people are peaceful and agree with each other, or when things seem right or suitable together: racial harmony (= good feelings between different races) domestic harmony (= good feelings in the family or home) Imagine a society in which everyone lived together in (perfect) harmony. We must ensure that tourism develops in harmony with the environment.
Once activated, helper T cells start to divide and to produce proteins that activate B and T cells as well as other immune cells. The killer T cell is specialized in attacking cells of the body infected by viruses and sometimes also by bacteria. It can also attack cancer cells. The killer T cell has receptors that are used to search each cell that it meets.
A answered. Lymphocytes are different from other types of white blood cells because they recognize and remember invading bacteria and viruses. T lymphocytes, or T cells, are responsible for cell-mediated immunity. T cells come in many types with specific functions, including: Helper T cells direct the immune system. In a rather lengthy process, helper T cells release cytokines. Cytokines stimulate B cells to form plasma cells. Plasma cells form antibodies, which stimulate the production of two other types of T cells: cytotoxic T cells and suppressor T cells. Helper T cells are the cells attacked by the AIDS virus. You can imagine the devastating effect of destroying the T cells that direct the immune system. Cytotoxic T cells release certain chemicals that break open to kill invading organisms.