Sensitized spleen B-cells in tolerance-resisting SJL mice

Effect of aging on immunological memory in gastrointestinal tract induced by sheep red blood cells in mice

Tolerance induction by oral administration of sheep red blood cells (SRBC) was investigated in young and aged mice. Two-month old C3H/He mice receiving oral administration of 8 X 10(9) SRBC a day for two weeks became tolerant to a subsequent SRBC challenge in the systemic immune system. In contrast, older C3H/He mice aged about 1 year old receiving the same treatment did not become tolerant but resisted tolerance induction and produced a prominent IgG memory in the systemic immune system. Autoimmune-prone NZB mice showed a similar resistance to tolerance induction even at 3 months of age. To investigate a possible role of the liver in the oral tolerance induction, young (2-month old) C3H/He mice received an injection of 1 X 10(8) SRBC via portal vein. The mice thus treated, were not tolerized at all but immunized. The results suggest that gut-associated local immune system play a key role in the induction of the oral tolerance and that the tolerance inducing function of the local immune system declines with aging. Antigens in the gut including denatured self antigens may immunize the systemic immune system of aged animals.

Developmental change in the second half of life--strategies for modification of selected compartments of aging

Age-related changes of different individuals multicentric and polymorphic. We have approached this problem of age-related changes by examining (1) membrane densities of receptors of various ligands in different organs, and (2) changes in different classes of T cells and of antibody response. Three strategies have been developed to modify progression of age-related changes to different extents in different compartments in which age-related changes occur. The first is based on administration of hormones, the second on administration of purine analogues and the third on administration of diets which differ in fatty acid content. Details of this last approach are reviewed in this paper. Lifespan of different species is a component of the evolution of each species. The variables which are decisive in the evolutionary processes which affect lifespans of different species are not necessarily variables which play a decisive role in the different health span of different individuals of the same species. For each individual of a given species, relative health span represents variations within the limits of the evolved lifespan of the species and depends on alleles of many different genes.

Isotype-specific resistance against tolerance induction in SJL mice

Age-related changes in antibody response of SJL mice were examined in terms of isotype expression after treatment with immunogen or with immunogen, preceded by the molecule in normally tolerogenic form. We report here that tolerance induction and resistance to down regulation are isotype specific. Tolerance can be induced in terms of all detectable isotypes at the age of 5 weeks. In older SJL mice, tolerance to the carrier is found in IgM antibody, whereas there is resistance against down regulation in terms of IgG2a and IgG2b isotypes, and sensitization in terms of IgG3, IgG1, and IgA antibody. Furthermore, the degree of down regulation is determinant dependent. This was observed when older SJL mice, pretreated with the carrier in a normally tolerogenic form, were immunized with haptenated carrier and tested for their response to hapten and carrier determinants. In this case, IgA antibody shows tolerance to the hapten and sensitization by carrier determinants.

Age- and strain-dependent polymorphism in IgE antibody against the phosphorylcholine hapten

The magnitude of the IgE antibody response against the phosphorylcholine (PC) hapten and the rate of age-related change of IgE formation is polymorphic in the three long-lived and six relatively short-lived strains of mice studied. Long-lived mice showed an early increase, followed by a decline in the levels of anti-PC IgE antibody. The rate of increase and decrease was strain dependent. Among short-lived strains, MRL/Mp-lpr and MRL/Mp-+ mice showed an early decline in IgE antibody. The extent and rate of decline with age was more rapid in MRL/Mp-lpr animals than in MRL/Mp-+ mice. In contrast, there was an early increase of IgE antibody in female SJL, NZB/BIN, BXSB/Mp and male BXSB/Mp. Thus, opposite age-related changes in IgE antibody production can occur in animals with a tendency to develop autoimmune disease. In hybrids of (SJL X BALB/c)F1 and (BALB/c X MRL/Mp-lpr)F1, the levels of IgE antibodies were higher than those observed in either parental strain, and declined steeply with advancing age. We suggest that this could be attributed to recessive inheritance.

Sensitization of T and B cells by a normally tolerogenic macromolecule: the induction of unresponsiveness and of sensitization is polymorphic

Changes induced in B and T cells by tolerogen were experimentally defined in animals which resist down-regulation. Female A/J, C57BL/6J, MLR/MpJ-lpr/lpr, MLR/MpJ-+/+ and NZB/B1NJ mice were injected at various ages with a tolerogenic form of rabbit gamma globulin (sRGG) or were left uninjected, and all were then immunized with dinitrophenylated RGG (DNP-RGG) on alum. The degree of tolerance was estimated by measuring anti-DNP and anti-RGG spleen plaque-forming cell (PFC) numbers. In some cases, the state of T or B cells deduced from these experiments was further examined by cell transfer experiments. Four types of responsiveness to the tolerogenic form of RGG (sRGG) were distinguished: 1) persistent tolerance inducibility of T and B cells to tolerance induction (A/J); 2) T cells retaining tolerance-inducibility after initiation of age-dependent sensitization of B cells by the tolerogenic form of RGG (C57BL/6J, NZB/B1NJ); 3) age-dependent resistance of T cells to tolerance-induction and age-dependent sensitization of B cells by tolerogen, with the sensitization only manifesting itself in reactivity with T cells from immunized donors (SJL/J); and 4) sensitization of T cells by a usually tolerogenic form of RGG (MLR/MpJ-lpr-lpr). Thus, the development of resistance against tolerance induction is highly polymorphic, not only with respect to the age of onset, but also with respect to the cellular site of its first manifestation and the effect. Possible mechanisms of B-cell sensitization in sRGG-treated C57BL/6 and NZB mice are discussed in relation to the age-dependent emergence of a B-cell subpopulation and of non-specific helper T-cell factors.

Dietary fat alters the fatty acid composition of lymphocyte membranes and the rate at which suppressor capacity is lost

SJL/J mice were fed from conception two nutritionally adequate semi-purified diets that differed only in polyunsaturated to saturated fatty acid content. The effect of diet fat on the fatty acid composition of membranes from spleen and thymus cells was determined. Diet fat was found to significantly alter the fatty acid composition of lymphocyte membrane phosphatidylcholine and phosphatidylethanolamine. Diet also altered the degree of resistance against tolerance-induction.