[Low-molecular immunomodulators of natural origin]

Area of Science:

• Immunology
• Microbiology
• Biochemistry

Background:

• Soil bacteria produce bioactive compounds with potential therapeutic applications.
• Low molecular weight peptides can modulate immune system functions.
• Understanding immunostimulatory effects is crucial for developing novel immunotherapies.

Purpose of the Study:

• To investigate the immunostimulating effects of two low molecular weight peptides (Nos. 1 and 2) derived from soil bacteria.
• To determine the impact of these peptides on specific immune responses, including antibody-forming cells (AFC) and delayed type hypersensitivity (DTH).
• To explore the optimal timing for peptide administration relative to immunization to maximize immune enhancement.

Main Methods:

• Bacterial peptide extraction and purification.
• Administration of peptides to immunized animals at various time points.
• Quantification of spleen AFCs via established immunological assays.
• Measurement of DTH responses and hemagglutinin levels in blood serum.

Main Results:

• Peptides Nos. 1 and 2 demonstrated a significant immunostimulating effect, increasing AFCs in the spleen by 2-4 times.
• Preparation No. 2, at doses of 0.5-25 mg/kg, elevated DTH and hemagglutinin levels.
• Optimal immune enhancement was observed when Preparation No. 2 was administered 24 or 48 hours post-immunization.
• The peptides showed efficacy against carcinoma 755 and were not toxic in vitro, suggesting a favorable safety profile.

Conclusions:

• Low molecular weight peptides from soil bacteria possess potent immunostimulating properties.
• These peptides can enhance key immune responses, offering potential as immunomodulatory agents.
• The findings support further research into these bacterial peptides for therapeutic applications, particularly in immunotherapy and oncology.