Table 2.

Aging and Macrophages

Alterations in macrophage function with advanced age	Reference
↓ Toll-like Receptor (TLR) expression (both mRNA and protein) and downstream signaling (in most but not all studies)	24,43–48
↓ Production of pro-inflammatory and immunomodulatory cytokines, including TNFα, IL-6, IL-1β, and CCL2 (MCP-1) after stimulation by a varity of agonists.	46–52
↓ Telomere length	53
↑ Regulators of immune signaling, such as A20, a de-ubiquitinase which, in turn, inhibits TLR signaling and NF-κB activation	11, 12
↓ Phagocytosis and pathogen clearance	7,51,54–59