Table 1. Summary of the changes in imuune system with aging.

Immunity	Cell	Aging-associated changes
Innate	Monocytes/macrophages	Phagocytic activity ↓
		MHC II expression ↓
		ROS and cytokine production ↓
	Dendritic cells	Maturation and antigen presentation ↓
		Altered TLR expression and signals
		Altered CD80 and CD86 expression
		Impared antigen uptake
	Neutrophils	Chemotaxis ↓
		MHC II expression ↓
		ROS and cytokine production ↓
		Altered TLR expression and signals
Adaptive	T cells	Naïve T cells ↓
		T cell response to new antigen ↓
		Numbers of senescent T cells and
		exhausted T cells ↑
	B cells	Naïve and circulating B cells ↓
		Antigen specific antibody production ↓
		Altered memory B cell homeostasis
		Limited diversity in BCR repertoire

MHC: major histocompatibility complex, ROS: reactive oxygen species, TLR: Toll-like receptor, BCR: B cell receptor.