Myelopeptides—Bone Marrow Mediators with Immunostimulating and Endorphin‐Like Activity

Abstract

Bone marrow cells produce soluble mediators with structural and functional heterogeneity. They were found to stimulate antibody production at the peak of the immune response, owing to compounds of a peptide nature (Mr 2000-1300). Active material was isolated by means of gel chromatography and electrophoresis. This material positively reacts with ninhydrin, and has maximum absorption close to 278 nm. Its antibody-stimulating activity decreased or stopped completely after treatment with proteolytic enzymes. Apart from the immunostimulating activity, bone marrow mediators have opiate-like activity. They have an analgetic effect, and interact with the opiate receptors of brain nerve cells. After a physicochemical and functional analysis, we conclude that bone marrow produces regulatory peptides that were previously unknown. We called them myelopeptides.