MIP-1α and MIP-1β (macrophage inflammatory protein) were originally co-purified from LPS stimulated mouse macrophages. Recombinant, mouse MIP-1β (rmMIP-1β) consists of 69 amino acids. MIP- 1β belongs to the chemokine β subfamily which is characterized by a C-C configuration at the first two cysteines. MIP-1β has endogenous pyrogenic activity when it is injected intravenously into rabbits. Although other cytokines, such as IL-1alpha, IL-1β and TNF have endogenous pyrogenic activity, the pyrogenic effects of these cytokines can be inhibited by cyclooxgenase blockers, while the pyrogenicity of MIP- 1β is unaffected by these agents. MIP-1β can synergize with the hematopoietic growth factors granulocyte macrophage CSF (GM-CSF) or macrophage CSF (M-CSF) to enhance colony formation.

MIP-1β has endogenous pyrogenic activity when it is injected intravenously into rabbits. MIP-1 can synergize with the hematopoietic growth factors granulocytemacrophage CSF (GM-CSF) or macrophage CSF (M-CSF) to enhance colony formation.

Lyophilized from a 0.2 μm filtered solution in 30% acetonitrile and 0.1% trifluoroacetic acid containing 0.5 mg bovine serum albumin

The biological activity of MIP-1β was tested in culture by measuring its ability to inhibit hematopoietic stem cell proliferation in an in vitro colony assay.