Question

Are there three main types of lymphocytes T-cells, B cells, and macrophages?

Answer 1

No, there are two types of lymphocytes: they are T- cells and B-cells. T-cells do not produce the antibody but help the B cells to secrete the antibodies. The immunity produced by the T cells is known as Cell-mediated immunity and that produced by the B cells is known as Humoral immunity. These lymphocytes are responsible for acquired immunity.

Complete answer:
A lymphocyte is a type of white blood cell that is part of the immune system. Which also secretes antibodies. They are mainly found in central lymphoid organs like the spleen and also found in the blood circulation. They are a type of White Blood Cells (WBCs). The lymphocytes originated from the stem cells. Macrophages are the White Blood Cells that engulfs and destroys the foreign organism by the process of phagocytosis. Macrophages are part of the Reticuloendothelial system and are found in all body tissues. They are also obtained from stem cells. The main difference between the lymphocytic cells and the macrophages is that the stem cells differentiate to form $2$ types of cells – common myeloid progenitor and common lymphoid progenitor. The common myeloid progenitor further divides to form the myeloblast from which the macrophages are formed. The lymphocytes are formed from the differentiation of the common lymphoid progenitor cells.

Note. :
The lymphocytes are responsible for immune reactions by the production of antibodies whereas the macrophages are mainly responsible for defensive reactions to some of the microorganisms and removal of the cell debris. The lifespan of the macrophages is $3$ days and the memory cells of both T and B lymphocytes can live life long. Other WBCs that are the parts of granulocytes include – eosinophil, basophil, and neutrophil.