Recombinant Brugia malayi pepsin inhibitor (rBm33) induced monocyte function and absence of apoptotic cell death: an in vitro study

Area of Science:

• Immunology
• Molecular Biology

Background:

• The Brugia malayi pepsin inhibitor (Bm33) is a potential target for filariasis treatment.
• Understanding the immunomodulatory effects of Bm33 on host immune cells is crucial for vaccine development.

Purpose of the Study:

• To investigate the effect of recombinant Bm33 (rBm33) on human monocyte/macrophage immune responses.
• To assess the impact of rBm33 on cytokine production, phagocytosis, and apoptosis.

Main Methods:

• THP-1 cells were stimulated with rBm33.
• Cytokine expression (IL-1β, TNF-α, IL-6, IL-12, IL-10) and inducible nitric oxide synthase (iNOS) levels were measured.
• Phagocytosis of GFP-expressing Escherichia coli was assessed.
• Apoptosis assays were performed on Peripheral Blood Mononuclear Cells (PBMCs).

Main Results:

• rBm33 stimulation led to increased pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) and decreased IL-12, iNOS, and IL-10 expression, indicating a Th1-biased response.
• rBm33 enhanced the uptake of E. coli by macrophages.
• No significant changes in nitric oxide (NO) levels were observed.
• rBm33 did not induce apoptosis in monocytes or lymphocytes from normal PBMCs.

Conclusions:

• rBm33 acts as an immunomodulator, stimulating macrophages to induce a Th1 immune response.
• rBm33 promotes phagocytosis and does not trigger apoptosis, suggesting its potential as a therapeutic or vaccine adjuvant.