Evaluation of the immunomodulatory effects of a South African commercial traditional immune booster in human peripheral blood mononuclear cells

Abstract

Background: With the burden of HIV and AIDS still very high, South Africa has seen an increase in commercial traditional medicines claiming to have immune-enhancing effects. Because of lack of regulation of the traditional medicine sector, these products have proliferated. This study aimed to evaluate the immunomodulatory effects of uMakhonya®, a commercial traditional immune booster, using various models of normal human peripheral blood mononuclear cells (PBMCs). Methods: Immunosuppressed, mitogen-, and peptidoglycan (PG)-stimulated PBMCs were treated with various doses of uMakhonya® and incubated for 24 h. The treated and control samples were analyzed for cytotoxicity, secretion of 12 different inflammatory cytokines, soluble interleukin-2 receptor (sIL-2R) levels, and nitric oxide (NO) secretion. Results: In cytotoxicity assays, uMakhonya® induced dose-dependent cytotoxic effects in all three models, with IC50 values of 512.08, 500, and 487.91 μg/mL for immunosuppressed, phytohaemagglutinin (PHA)-, and PG from Staphylococcus. aureus (PG-S. aureus)-stimulated PBMCs, respectively. UMakhonya® at 100 and 10 μg/mL induced a significant (p < 0.05) increase in the secretion of IL-1α, IL-1β, IL-6, IL-10, tumor necrosis factor alpha (TNF)-α, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in cyclosporine-, immunosuppressed, and PHA-stimulated PBMCs. In the same samples, there was a significant increase (p < 0.05) in sIL-2R concentration, which correlated with an increase in the secretion of inflammatory cytokines. In PBMCs stimulated with PG-S. aureus, uMakhonya® at doses of 100 and 10 μg/mL significantly (p < 0.05) suppressed the secretion of inflammatory cytokines, especially IL-1β and TNF-α. PG-S. aureus-stimulated PBMCs also showed a significant decrease (p < 0.05) in sIL-2R concentration when compared to control samples. UMakhonya® insignificantly (p > 0.05) decreased NO levels in PBMCs after PG-S. aureus stimulation. Conclusions: These results showed that uMakhonya® can induce both pro-inflammatory and anti-inflammatory effects depending on the initial stimuli applied to immune cells.