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Table 1 Age-related changes to the immune system, adapted from [3]

From: Understanding how we age: insights into inflammaging

Immune system Cell type Age–related changes
Innate immunity Neutrophils Reduced phagocytic ability of opsonized bacteria and impaired superoxide production
Monocytes or macrophages Reduced levels of MHC class II complexes, reduced phagocytic ability and impaired superoxide production
Dendritic cells Impaired capability to phagocytose apoptotic cells; impaired migration
Natural killer cells Reduced cytotoxicity
Acquired immunity T cells Thymus atrophy
Reduced naïve cells leaving thymus, severely contracted T-cell repertoire after 70 years
Impaired expansion and differentiation
Increased proinflammatory cytokine release, reduced IL-2 production
Increased memory and effector cells
Impaired T-cell help of B cells
Reduced regulatory T cells; possible increased inflammation and autoreactivity
Expanded clones of herpes virus (for example, cytomegalovirus) CD8+ cells, dominating the T-cell repertoire and limiting response to other pathogens
B cells Reduced number of mature B cells leaving bone marrow
Increased memory B cells, decline in naïve B- cells
Reduced responsiveness to stimulatory molecules
   Impaired antibody response to vaccination
  1. MHC, major histocompatibility complex.