Final answer:
B cells are immune cells that produce antibodies, while T cells are another type of lymphocyte involved in the immune response. Both B and T cells recognize specific pathogens through the binding of antigens.
Step-by-step explanation:
B cells are immune cells that function primarily by producing antibodies. An antibody is any of the group of proteins that binds specifically to pathogen-associated molecules known as antigens. An antigen is a chemical structure on the surface of a pathogen that binds to T or B lymphocyte antigen receptors. Once activated by binding to antigen, B cells differentiate into cells that secrete a soluble form of their surface antibodies. These activated B cells are known as plasma cells.
T cells
Lymphocytes: B Cells, T Cells, Plasma Cells, and Natural Killer Cells
As stated above, lymphocytes are the primary cells of adaptive immune responses. The two basic types of lymphocytes, B cells and T cells, are identical morphologically with a large central nucleus surrounded by a thin layer of cytoplasm. They are distinguished from each other by their surface protein markers as well as by the molecules they secrete. While B cells mature in red bone marrow and T cells mature in the thymus, they both initially develop from bone marrow.
T cells migrate from bone marrow to the thymus gland where they further mature. B cells and T cells are found in many parts of the body, circulating in the bloodstream and lymph, and residing in secondary lymphoid organs, including the spleen and lymph nodes. B and T cells must be "switched on" in order to fight a specific pathogen. Once this happens, they produce an army of cells ready to fight that particular pathogen. Pathogens have proteins, often located on their cell surface. These proteins are called antigens. An antigen is any protein that causes an immune response because it is unlike any protein that the body makes. Antigens are found on bacteria, viruses, and other pathogens.
Summary
- B cells produce antibodies against pathogens in the blood and lymph.
- Killer T cells destroy body cells infected with pathogens.