Monoamines as immunomodulators: importance of suppressors and helpers of the bone marrow.

The intraimmune pathways and mechanisms of action of the serotoninergic and dopaminergic systems in exerting a modulating effect upon immunogenesis are presented. Experiments were carried out in mice immunized with sheep red blood cells (1 X 10(7); 5 X 10(6)). Participation of the hypothalamic-pituitary complex in the monoaminergic mechanisms of stimulation and inhibition of rosette formation was revealed. Dissection of the pituitary stalk prevented stimulation of rosette formation by apomorphine (1 mg/kg i.p) and bupropion (20 mg/kg) and the reduction of the immune response by haloperidol (1 mg/kg), 5-hydroxytryptophan (300 mg/kg) and serotonin (50 mg/kg). The results of syngeneic cellular transfer of different immunocompetent organs showed that serotonin injection induced an increase in B-suppressor activity of bone marrow cells, reaching maximal value in the inductive period (day 3 of the immune response). B-Lymphocyte suppression in donors not treated with serotonin peaked on day 5 of the immune response. Stimulation of the immune response under activation of the dopaminergic system after apomorphine administration was provided by an increase in T-helper activity in the bone marrow cells, mainly with respect to IgM-response. The suppressive activity of bone marrow T cells on IgM- and IgG-immune responses was increased in nonimmunized donors treated with serotonin or haloperidol. The mechanisms of neurochemical multichannel immunomodulation by means of redistribution of cellular populations resulting in an increase in suppressors or helpers in bone marrow are discussed.