Lymphocytes are specific Immune cells; there are two types: B cells and T cells
B cells (bonemarrow maturation) respond to antigens from: bacteria, bacterial toxins and free-viruses, they produce antibody/immunoglobulin; some B cells respond to a antigen with the help of helper T cells and others respond directly
T cells (thymusgland maturation) respond to bacteria and virus-infected host cells
Helper T (T_h) (CD4^+) cells - stimulate action of T_k cells and stimulate B cells to divide and produce plasma cells
Killer T (T_k) (CD8^+) cells - destroy virus infected body cells by; attaching to pathogen, and secreting preforin (‘punches’ holes in cell membrane leading to cell lysis)
Regulator T (T_r) cells - suppress the B cells by inhibiting the T_h cells; regulates amount of antibody produced, shuts down the immune response
