B-lymphocytes (B-cells) and T-lymphocytes (T-cells) are two special types of lymphocytes in our blood responsible for acquired immunity. B-cells are responsible for antibody-mediated immunity response — they produce antibodies to fight pathogens. T-cells are responsible for cell-mediated immunity response; they don't secrete antibodies themselves but help B-cells produce them. Both B-cells and T-cells together protect the body from diseases caused by pathogens.