Adaptive immunity is specific for certain antigens, and it remembers antigens that it has encountered previously. Lymphatic tissue, specifically red bone marrow and the thymus, produces B and T cells. Both B and T cells play roles in the adaptive immune response. T cells can be either helper T cells (CD4 T cells) or cytotoxic T cells (CD8 T cells). CD4 T cells directly attack antigens in cell-mediated immunity whereas in antibody-mediated immunity, the B cells make antibodies that inactivate specific antigens. Helper T cells help in both cell-mediated and antibody-mediated immune responses. If a pathogen is within the cell, then cell-mediated immunity will be initiated. If the pathogen is extracellular, then antibody-mediated immunity, also known as humoral immunity, will be the body’s choice of defense. T cells are inactive until they are activated by an antigen and a costimulatory substance, such as cytokines or plasma membrane
Adaptive immunity is specific for certain antigens, and it remembers antigens that it has encountered previously. Lymphatic tissue, specifically red bone marrow and the thymus, produces B and T cells. Both B and T cells play roles in the adaptive immune response. T cells can be either helper T cells (CD4 T cells) or cytotoxic T cells (CD8 T cells). CD4 T cells directly attack antigens in cell-mediated immunity whereas in antibody-mediated immunity, the B cells make antibodies that inactivate specific antigens. Helper T cells help in both cell-mediated and antibody-mediated immune responses. If a pathogen is within the cell, then cell-mediated immunity will be initiated. If the pathogen is extracellular, then antibody-mediated immunity, also known as humoral immunity, will be the body’s choice of defense. T cells are inactive until they are activated by an antigen and a costimulatory substance, such as cytokines or plasma membrane