Apa from T & B lymphocytes, the other class of lymphocytes is -

Lymphocytes include natural killer cells (NK cells) (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). Reff: Ananthanarayanan & panikers textbook of microbiology 9th edition pg:132