Influence of bone marrow hexapeptides (myelopeptides) on antibody production and algesthesia in mice and the dependence of these effects on naloxone

Abstract

It is shown that synthetic analogs of two bone marrow hexapeptides (myelopeptides 1 and 2), which are identical in structure to the N-terminal peptide fragments of hemoglobin ~-and 15-chains, are characterized by naloxone-independent antibody-stimulating activity. The antibody-stimulating effect of the myelopeptides becomes naloxonedependent and stronger against the background of immunosuppression provoked by the hot plate test carried out before immunization. Intraperitoneal administration of both myelopeptides in doses of 10-13-10 -g g/mouse causes a naloxone-dependent modulatory effect on mouse algesthesia threshold with a predominant analgetic effect. Key words: antibody production; algesthesia threshold; naloxone; hexapeptidesIt is known that bone marrow cells of various animal species and of human origin produce humoral factors (myelopeptides -MP) which influence immune response development and algesthesia [3,10]. There are reports that MP can produce dose-dependent opposite effects on algesthesia correlating with the immune response [1,13]. The presence of opioid peptides in MP and the naloxone-dependence of its antibody-stimulating and analgetic effects point to the participation of bone marrow opioids along with other MP in the realization of these effects [2,10]. However, the identification of individual MP molecules responsible for immuno-and neurotropic properties requires their isolation from the mixture.At present two such compounds, MP1 and MP2, are structurally characterized. They are The objective of the present investigation was to study the influence of hexapeptides on antibody production and algesthesia in mice and the dependence of these effects on naloxone. MATERIALS AND METHODSExperiments were carried out on (CBAxC57B1/6) F 1 hybrid mice and on CBA strain mice of 18-20 g weight. Mice were immunized with a single intraperitoneal injection of 0.5 ml of 5% or 0.05% sheep red blood cell suspension 20, 60, or 180 min after algesthesia threshold (AT) determination.The enhancing effect of MP1 and MP2 on antibody production was-assessed by estimation of the number of antibody-producing cells (APC) in 0007-4888/95/0004-0400512.50 9Plenum Publ/shing Corporation