What types of immunocompetent cells are formed in the body? What are their functions?

The main types of immunocompetent cells are macrophages, T-lymphocytes (T-killers, T-helpers, T-suppressors) and B-lymphocytes.
Macrophages in a special way split foreign objects, and then place their antigenic fragments on their own membrane and present them to T-lymphocytes for recognition.
T-helpers with the help of membrane receptors recognize certain antigens, and then activate other types of lymphocytes, in particular, B-lymphocytes.
B-lymphocytes activated by T-helpers multiply (form clones), and then they intensively produce antibodies (immunogolbulins). Activated B lymphocytes are called plasmocytes (plasma cells). Antibodies enter the blood, lymph, tissue fluid, spread throughout the body and specifically bind to certain antigens, rendering them harmless. In this case, antigen-antibody complexes are formed, which are then recognized and absorbed by phagocytes.
T-killers with the help of membrane receptors specifically recognize and destroy cells infected with viruses, and other “defective” cells, for example, tumor cells.
T-suppressors control the strength and duration of the immune response. If there were no T-suppressors, the immune response would increase and become uncontrollable.