Abstract
'Intrinsic immunity' is often used to refer to mechanisms of host defense operating in nonleukocytic cells. This term can refer to the intrinsic capacity of an individual cell to fend off invading microbes without help from other cells or of a group of similar cells to fend off invading microbes without help from other cell types. The intrinsic capacity of individual cells to defend themselves against invading microbes without assistance has received little attention and is the topic of this review. We also focus on nonleukocytic cells and on humans, the only species in which intrinsic immunity has been shown by genetic means to be essential for homeostasis in natural conditions at whole-body level. We review recent progress in our understanding of the type I interferon-independent intrinsic immunity of individual nonleukocytic cells, as inferred from human inborn errors of intrinsic immunity manifesting as infection or autoinflammation.