Immune-related alterations in aged gut-associated lymphoid tissues in mice

Abstract

To study whether senescence-induced changes in the gut-associated lymphoid tissue (GALT) are mainly quantitative, several parameters were examined in three age groups of BALB/c mice (1-2, 12-14, and 24-28 months old). A substantial senescence-associated decline in the number of lymphoid cells was found in the mesenteric lymph nodes (MLN) and spleen (SPN), and especially in the Peyer's patches (PP), but not in the lamina propria (LP). The distribution of lymphocyte subsets in these tissues was also altered with an absolute reduction of T cells--in particular, a L3T4+ helper/inducer T-cell marker-bearing subset. These changes were most remarkable in PP, followed by MLN. The in vitro proliferative reactivity and the production of each isotype-specific immunoglobulin (Ig) by PP, MLN, and SPN were profoundly affected when T-cell-dependent (Td) B-cell mitogens were used, but minimally affected when T-cell-independent (Ti) B-cell mitogens were used. The isotype-specific Ig content of small-intestinal perfusates was also influenced by aging, but only to a minor extent, as exemplified by a decrease in IgA levels in the fasting condition. Thus, despite the defects in the quantity and distribution of lymphocytes in aged PP and MLN, the finding of little change in the total amount of secreted IgA in aged intestine suggests that gut IgA-mediated luminal immune responses could remain nearly unaltered with senescence. The constancy of intraluminal IgA levels could be of physiological significance in host defense at the gut mucosal surface in aged mice.

Basis for the Age‐related Decline in Intestinal Mucosal Immunity

“…Follicle weight and the yield of PP lymphocytes have been reported to decline with increasing age in mice (Kawanishi and Kiely, 1989). However, our own studies have shown that neither the number of PPs in young adult, mature and senescent rats, i.e.…”

Effects of Ageing on the Immunoregulation of Parasitic Infection

“…Populations of CD4 ϩ and CD8 ϩ T cells within the Peyer's patches, naïve CD4 ϩ cells within the MLN, and IL-2 production do not show the same age-associated decline as seen elsewhere (6,11,21,32). However, reduced numbers of Th2 cells and lower levels of Ag-specific IgG and IgA have been noted within the GALT (22,28). To ascertain whether these reported changes within the GALT influence the immune response occurring in the context of parasite invasion of intestinal mucosa and to confirm whether the altered cytokine milieu seen is real and not an artifact of ex vivo restimulation we looked directly at cytokine protein and mRNA production within cecum.…”

Local and systemic immune response in community-dwelling elderly after intranasal or intramuscular immunization with inactivated influenza vaccine

“…The ability to secrete IgA into the saliva in humans does not diminish significantly with age [Finkelstein et al, 1984], nor does the total amount of secreted IgA in the intestine of old mice compared to IgG [Kawanishi and Kiely, 1989].…”