Macrophage Inflammatory Proteins (MIP) belong to the family of chemotactic cytokines known as chemokines.

MIP-1α and MIP-1β are major factors produced by macrophages and monocytes after they are stimulated with bacterial endotoxin[5] or proinflammatory cytokines such as IL-1β.

They also induce the synthesis and release of other pro-inflammatory cytokines such as interleukin 1 (IL-1), IL-6 and TNF-α from fibroblasts and macrophages.

[10] Biophysical analyses and mathematical modelling has shown that MIP-1 reversibly forms a polydisperse distribution of rod-shaped polymers in solution.

Polymerization buries receptor-binding sites of MIP-1, thus depolymerization mutations enhance MIP-1 to arrest monocytes onto activated human endothelium.

It is produced mainly by macrophages, monocytes and epithelial cells and is responsible for chemotaxis to the source of inflammation and activation of neutrophils.

It has chemotactic properties for monocytes and eosinophils and is expressed by macrophages, basophils and some tissue cells.