Presence of Impairment of Humoral Immunity in Nonadherent Spleen Cells of Old Mice

Spleen cells from aged mice when cultured in vitro with sheep red blood cells (SRBC) generate fewer antibody-forming cells than do cells from young mice. To define further the nature of the decrease in response with age, we separated spleen cell suspensions from young and old mice into two populations on the basis of their ability to adhere to plastic Petri dishes and their activity was assessed in various combinations with SRBC. Old adherent cells cultured with young nonadherent cells responded fully to the antigen, whereas old nonadherent cells combined with young adherent cells gave a response comparable to unseparated old spleen cells. Similar results were obtained when adherent cells were exposed to SRBC, washed free of the antigen, then recombined with the nonadherent cells. The results demonstrate that the adherent cells of old spleens are indistinguishable from those of young spleens in their ability to initiate antibody response, but the activity of nonadherent cells of old spleens is impaired.