Immunology  1986 Jun;58(2):329-34 

Effects of antigen and internal environment on anti-phosphorylcholine immune
responses of autoimmune aged NZB/W F1 mice.

Seoane R, Faro J, Eiras A, Lareo I, Couceiro J, Regueiro BJ.

The idiotypic profile of anti-phosphorylcholine plaque-forming cell responses
and their evolution with ageing were studied in (NZB X NZW) F1 mice. Our results
showed that the anti-phosphorylcholine plaque-forming cell response induced by
phosphorylcholine coupled to keyhole limpet haemocyanin and, paralleling, the
T15 idiotype clonal dominance declined with ageing. This loss of immune
competence was also observed with another thymus-dependent (phosphorylcholine
coupled to egg globulin) as well as thymus-independent (capsular polysaccharide
of Streptococcus pneumoniae strain R36a) antigens. In contrast, old mice
challenged with an antigenic preparation of Neisseria meningitidis showed an
immune response not significantly different from that elicited by the same
antigen in young mice. The hapten-augmentable plaque-forming cells were assayed
to determine whether a putative auto-antiidiotypic regulation underlies this
loss of immune competence. Only minimal numbers and non-significant differences
between young and old mice immunized with any antigen could be detected. Further
studies using an adoptive transfer system demonstrated that cells from aged mice
were able to support a normal anti-phosphorylcholine response when transferred
into lethally irradiated young recipients. Our results suggest that no permanent
cellular defects, but rather internal environment or/and radioresistant
suppressor cells, are involved in this loss of immune competence. The role
played by these factors and their effect on distinct subpopulations of B cells
are discussed.