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.
Defining the role of the human thymus in reconstituting the peripheral T cell pool is important in the setting of bone marrow transplantation, cancer chemotherapy, and AIDS (1). T cell reconstitution by the thymus has the advantage of regenerating complete T cell repertoires capable of responding to new Ag challenges.