A common problem for the purple leaf plum tree is blossom blight, in which first the flowers, then young leaves, turn brown and wither, according to Grow Fruit by Alan Buckingham.
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.
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.