Immunostimulatory mouse granuloma protein.

Area of Science:

• Immunology
• Biochemistry
• Cell Biology

Background:

• Subcutaneous talc-induced granuloma extracts in mice confer protection against Listeria monocytogenes.
• The specific active factor responsible for this protection remained uncharacterized.

Purpose of the Study:

• To purify and characterize the protective factor from mouse granuloma extracts.
• To assess the biological activity and potential therapeutic applications of the purified factor.

Main Methods:

• Purification using ammonium sulfate fractionation, preparative electrophoresis, gel filtration chromatography, isoelectric focusing, and preparative polyacrylamide gel electrophoresis.
• Homogeneity assessment via NaDodSO4/polyacrylamide gel electrophoresis, revealing a single band with Mr 55,000.
• Characterization of migration with alpha 1-globulins and isoelectric point determination (pI 5 +/- 0.1).

Main Results:

• A homogeneous protein, termed "mouse granuloma protein," was isolated.
• The protein's biological activity was sensitive to Pronase but not trypsin.
• Intravenous injection of 5 micrograms of mouse granuloma protein conferred complete protection against lethal Listeria monocytogenes.
• Incubation of mouse peritoneal cells with 10 nM mouse granuloma protein induced cytostatic activity against Lewis carcinoma cells.

Conclusions:

• Mouse granuloma protein is a key mediator of protection against Listeria monocytogenes.
• The purified protein exhibits immunomodulatory properties, including anti-cancer cell activity.
• This protein represents a potential therapeutic agent for infectious diseases and cancer immunotherapy.