Isolation of interleukin-1 from human milk.
Human milk was investigated in regard to the presence of lymphocyte growth factors. Precipitated and dialyzed protein from mature human milk was found to exhibit interleukin-1 (IL-1) activity in the murine thymocyte proliferation assay. A mitogenic effect of milk protein was also observed in cultures of human and guinea pig thymocytes, demonstrating that the effect was not species restricted. No interleukin-2 or thymocyte growth peptide activity was found. Gel filtration chromatography on Sephadex G 150 revealed three distinct peaks of IL-1 activity, with apparent molecular weights of 14, 31 and 60 kilodaltons, respectively. Chromatofocusing showed IL-1 activity in four peaks, the major peak eluting at an isoelectric point of 5.0. Similar molecular heterogeneity has previously been demonstrated for IL-1 isolated from macrophages and other sources. The physiological role of milk-derived IL-1 is unknown, but it is proposed that it might act as an immunostimulating factor in the mammary gland, and hypothetically also in the breast-fed infant. Since IL-1 is a potent pyrogen, it is also suggested that milk-derived IL-1 contributes to the well-known pyrogenic activity of milk.
D000818:Animals; D002850:Chromatography, Gel / Q000379:methods; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1 / Q000302:isolation & purification*; D007376:Interleukin-2 / Q000302:isolation & purification; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008895:Milk, Human / Q000032:analysis*; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification; D013601:T-Lymphocytes / Q000187:drug effects
D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1; D007376:Interleukin-2; D010455:Peptides; C052275:thymocyte growth peptide