| Popis: |
Immunosenescence occurs after maturation and is expressed as a series of failing immunologic functions. Aging is best studied in the peripheral organs of the immune system such as lymph nodes, spleen, and isolated lymphoid tissues. The functional immunological building blocks of peripheral lymphoid organs are the lymphoid follicles. Aging defects occur in the components of lymphoid follicles, such as the T cells, B cells, and accessory cells, e.g., the dendritic cells. Among the dendritic cells, the most influential on the aging humoral immune response is the follicular dendritic cell (FDC). In aged mice, the Ab response is depressed because of the reduced capacity of FDCs to trap ICs needed for stimulation of B cells. This path is interrupted by the 70% age-related reduction of FcγRII on FDCs and the 88% age-related reduction in IC trapping. Thus, we conclude that these reductions account, in large part, for the declining Ab response in aged animals. |
