Myelopeptides. Mediators of interaction between the immune system and the nervous system

Bone marrow immunoregulatory peptides (myelopeptides): isolation, structure, and functional activity

Myelopeptides (MPs) are bioregulatory mediators of bone marrow origin. Several individual MPs have been isolated from the supernatant of porcine bone marrow cell culture by successive solid phase extraction and reversed-phase high performance liquid chromatography. Two of them, MP-1 (Phe-Leu-Gly-Phe-Pro-Thr) and MP-2 (Leu-Val-Val-Tyr-Pro-Trp), were synthesized and their biological activities were comprehensively studied. Both hexapeptides display pronounced immunoregulatory activity but their final effects as well as mechanisms of action are different. Peptides MP-1 and MP-2 are identical to conservative fragments 33-38 alpha- and 31-36 beta-chains of hemoglobin, respectively. The sequences of other isolated MPs have no homology with any functional protein. The role of MPs in bioregulatory processes in vivo is discussed.

Immunoregulatory effects of two bone-marrow hexapeptides (myelopeptides) in experimental models of immunodeficiency

Myelopeptide 1 (MP-1, Phe-Leu-Gly-Phe-Pro-Thr) and myelopeptide 2 (MP-2, Leu-Val-Val-Tyr-Pro-Trp) are hexapeptides originally isolated from porcine bone-marrow cell culture. MP-1 enhanced the number of antibody-forming cells in NZB mouse spleen cells in vitro and increased the antibody production in Cy-treated (CBAxC57B1/6)F1 mice in vivo. MP-1 increased ConA-induced proliferation of both NZB spleen cells in vitro and spleen cells of Cy-treated mice in vivo. MP-1 restored polyclonal IgG synthesis depressed by PWM in the NZB spleen cell culture. MP-2 also evoked immunoregulatory effects which were less pronounced and realized at higher concentrations than effects of MP-1. Neither MP-1 nor MP-2 affected LPS-induced spleen cell proliferation in both NZB- and Cy-treated (CBAxC57B1/6)F1 mice.

Myelopeptides: bone marrow regulatory mediators

Bone marrow cells of various animal species and men produce a group of bioregulatory peptides called myelopeptides (MPs). A highly purified MP fraction and some individual molecules have been isolated from the supernatant of porcine bone marrow cell cultures by reverse phase chromatography. MPs have a wide spectrum of functional activities: immunoregulatory, differentiating and opiate-like. They evoke 2.5-fold stimulation of antibody production to various antigens. They correct some immune defects in MRL/lpr mice with spontaneous autoimmune disorders that results in 2-fold prolongation of the life span of these mice. MPs influence the differentiation of bone marrow and peripheral blood cells derived from healthy and leukemic donors. They induce terminal differentiation in the leukemic human HL-60 cell line. MPs also show an effect on pain sensitivity. A new immunocorrective drug Myelopid has been developed on the basis of MP mixtures. This drug is effectively used in Russia both in medicine and veterinary practice for prophylaxis and treatment of diseases accompanied by immunodeficiency. Two individual MPs were isolated and identified: Phe-Leu-Gly-Phe-Pro-Thr (MP-1) and Leu-Val-Val-Tyr-Pro-Trp (MP-2). MP-1 displays immunoregulatory activity; MP-2 abolishes the inhibitory effect of leukemic cells on T-lymphocyte functional activity. MPs seem to provide not only immunoregulation but also to participate in complex interactions between different systems in the organism.

Immunoregulatory properties of hexapeptide isolated from porcine bone marrow cell culture

Myelopeptide 1 (MP-1) is hexapeptide originally isolated from porcine bone marrow cell culture. It was synthesized and its immunoregulatory properties were studied. MP-1 caused a 1.5-2-fold dose-dependent increase of antibody production in the culture of mouse immune lymph node cells. It abolished Con A induction of T suppressors in the suspension of mouse spleen cells and counteracted the inhibitory effect of T suppressors on antibody production. The inoculation of MP-1 (1 x 10(-9) g/mouse) to mice two weeks after their gamma-irradiation (2 Gy) resulted in an increase of antibody production up to 80.2 +/- 15.5% as compared to that in the irradiated control 37.6 +/- 12.0%. Immunofluorescent analysis revealed the specific binding of MP-1 with receptors on the target cells in the suspension of mouse spleen cells. It is supposed that MP-1 participates in the immunoregulatory processes in the living organism.

Immunomodulating activity of myelopeptides: clinical trials

Bone marrow cells of various animal species and the human produce a group of bioregulatory peptides called myelopeptides (MPs). A highly purified myelopeptide (MP) fraction and some individual molecules have been isolated from the supernatant of the porcine bone marrow cell culture by successive gel chromatography and HPLC. Myelopeptides have a wide spectrum of functions including immunoregulatory, differentiating, and opiate-like activities. A new immunoreactive drug, Myelopidum, has been created on the basis of myelopeptides. This drug is effectively used in Russian medicine for treating diseases accompanied by immunodeficiency and in veterinary practice for prophylaxis and treatment of newborn and young animals with such diseases as pneumonia and enteritis. Treatment of patients by Myelopidum after major surgery prevents 50 to 70 percent of postsurgical complications, particularly postsurgical pneumonia. Myelopidum normalizes the number and balance of T helper and T suppressor cells and B lymphocytes in patients with chronic pulmonary diseases and promotes the beneficial clinical effect of significant prolongation of periods of remission.