This paper at Aging & Immunity takes a look at just a few detailed biochemical changes in the aging immune system (and the full PDF format paper is freely available). It's another perspective on inflammaging, and you'll notice that calorie restriction emerges again as a beneficial practice: "The mechanism explaining the increased disease susceptibility in aging is not well understood. CD8+ T cells are crucial in anti-viral and anti-tumor responses. Although the chemokine system plays a critical role in CD8+ T cell function, very little is known about the relationship between aging and the T cell chemokine system. ... we have examined the effect of aging on murine CD8+ T cell chemokine receptor gene expression. Freshly isolated splenic CD8+ T cells from [old] mice were found to have higher CCR1, CCR2, CCR4, CCR5 and CXCR5, and lower CCR7 gene expression compared to their younger cohort. ... caloric restriction selectively prevents the loss of CD8+ T cell CCR7 gene expression in aging to the level that is seen in young CD8+ T cells. ... These findings are consistent with the notion that aging exists in a state of low grade pro-inflammatory environment." Receptors are a part of cellular biochemical programming, determining interaction and response. Change the balance of receptors and you change the capacity of the cell. Here, you're looking at the innermost workings of the grand machine we endeavor to understand, and then repair.