In vitro study on the immunological effect of bromelain and trypsin on mononuclear cells from humans.

BACKGROUND: Proteolytic enzymes such as bromelain and trypsin are used as an adjuvant therapeutic approach in the treatment of chronic inflammatory, malignant and autoimmune diseases. In vitro studies have shown that proteolytic enzymes modulate surface adhesion molecules on T-cells. In this study we analysed the influence of bromelain and trypsin on the cytokine production and proliferation of peripheral blood mononuclear cells (PBMC) from patients with a classical cellular mediated autoimmune disorder, namely encephalomyelitis disseminata (ED) as well as from healthy controls. -

METHODS: PBMC from patients with ED (n=12) and healthy controls (n=12) were cultured for seven days at 37 degrees C under three different conditions: without antigen, with bromelain and with trypsin (final concentrations 10-1000 microg/ml). Proliferation was determined by superset3H-thymidine incorporation. Secretion of cytokines into the supernatant was measured by a double sandwich ELISA. Intracellular cytokines were determined by flow cytometric analysis. -

RESULTS: PBMC from patients with ED and healthy controls showed a significantly increased proliferative response to bromelain (ED: 14053+/- 7585 cpm with bromelain vs. spontaneous proliferation of 430+/- 255 cpm; healthy controls: 10689+/- 4607 cpm vs. 327+/-193) but not to trypsin. Bromelain induced in all 24 individuals a significant increase of the macro-phage/monocyte associated cytokines interleukin (IL)-6, granulocyte-macrophage-colony stimulating factor (GM-CSF), tumour necrosis factor alpha (TNFa) (p<0.01) as well as of the type 1 cytokine gamma-interferon (IFNgamma). In contrast, the type 2 cytokines IL-4 and IL-5 were not induced. Flow cytometric analysis revealed a significant increase of IFNgamma-producing CD4+ T-cells. There were no differences in cytokine production between ED patients and healthy controls. -

CONCLUSION: These results indicate that bromelain - but not trypsin - activates macrophages/monocytes and type 1 cells independently from the underlying disease and may stimulate, therefore, the innate as well as the adaptive immune system.