Pharmacology of ribosomal immunotherapy.

The use of immunostimulating drugs is one way to intervene in the immune system. Many of these agents are of bacterial origin and most are able to stimulate the nonspecific immune response by acting on polymorphonuclear cells (PMNs) and macrophages. Ribosomal immunotherapy ('Ribomunyl') contains both proteoglycans from Klebsiella pneumoniae and ribosomes from 4 different bacterial strains. It can stimulate not only macrophages but also specific antibody production. 'Ribomunyl' has been shown to stimulate many of the functions of PMNs, specifically the formation of oxygenated free radicals, chemotaxis and adhesion. The effect of 'Ribomunyl' immunostimulant on the properties of macrophages is of special interest, as these cells participate in both the nonspecific immune response (phagocytosis, proinflammatory cytokine production) and the specific immune response (antigen processing and presentation, lymphocyte proliferation). 'Ribomunyl' has been shown to increase the production of many cytokines [interleukin (IL)-1, IL-6, IL-8, tumour necrosis factor-alpha and colony-stimulating factor], leading to the activation of the cytokine network. 'Ribomunyl' was also able to stimulate natural killer cells involved in viral immunity. Because of the presence of ribosomes from 4 frequently encountered bacterial strains, 'Ribomunyl' has specific immunostimulant properties. This has been clearly demonstrated in animals and humans, where specific antibody-forming B cells were found in the tonsils after oral administration. However, specific T-cell response has not been reported, suggesting that 'Ribomunyl' could act directly on B cells such as T-cell-independent bacterial antigens.