Lack of age-associated immune dysfunction in mucosal-associated lymph nodes.

The magnitude of the immune response in old and young mice to trinitrophenylated bovine gamma-globulin was measured in various lymphatic sites at a cellular level using the plaque-forming cell assay. As we have previously shown, the number of splenic IgM, IgG, and IgA anti-TNP PFC progressively declined in aging C57BL/6J male mice. In addition, mice receiving antigen in the 4 footpads and the base of the tail exhibited similar decline in the number of PFC in the draining peripheral lymph nodes with increasing age. In contrast, mesenteric and mediastinal lymph node IgM, IgG, and IgA anti-TNP PFC response to TNP-BGG in complete Freund's adjuvant, i.p. or via gastric intubation, in old mice remained unimpaired compared with the number in younger mice. The data support the view that the mucosal-associated lymphoid system differs from the systemic system with regard to immune competence with age. Furthermore, the findings imply a site preference for a decline in immune function with aging.