Table 4 Overview of the defining features of innate and adaptive immunity [1]
Innate immune system | Adaptive immune system | |
|---|---|---|
Cells | Hematopoietic cells: • Macrophages • Monocytes • Dendritic cells • Mast cells • Neutrophils • Basophils • Eosinophils • NK cells Non-hematopoietic cells: • Epithelial cells (skin, airways, gastrointestinal tract) • Endothelial cells | Hematopoietic cells: • T cells • B cells Dendritic cells (APCs) |
Molecules | • Cytokines • Complement • Proteins and glycoprotein | • Antibodies (Ig) • Cytokines |
Response time | • Immediate | • Delayed by hours to days |
Immunologic memory | • None: responses are the same with each exposure | • Responsiveness enhanced by repeated antigen exposure |