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[Physicochemical properties of the human lymphocyte mitogenic factor induced by phytohemagglutinin]
Abstract:
Some physical and chemical properties of the mitogenic factor (MF) produced in vitro by PHA-stimulated human lymphocytes were investigated. Treatment of the culture medium with proteases proved to decrease the MF activity sharply. The MF was found to have an elution pattern in Sephadex and Bio-gel gels similar to proteins with the molecular weight of 20 000--30 000 daltons (peak--25 000). In experiments with the MF fractionation by disc-electrophoresis on 5% polyacylamide gel the MF formed a few discrete peaks in the fractions corresponding to the mobility of alpha1- and alpha2-globulins and transferrin. In isoelectric focusing the MF formed 3 fractions in the pH range of 4.5--8.3. Functional heterogeneity of the MF is suggested.
Insights
Researchers investigated the properties of mitogenic factor (MF) from human lymphocytes. Protease treatment reduced MF activity, suggesting a protein nature with a molecular weight of 20,000-30,000 daltons.
Area of Science:
- Immunology
- Biochemistry
- Molecular Biology
Background:
- Human lymphocytes stimulated by phytohemagglutinin (PHA) produce a mitogenic factor (MF).
- Understanding the physical and chemical properties of MF is crucial for its role in immune responses.
Purpose of the Study:
- To characterize the physical and chemical properties of the mitogenic factor (MF).
- To determine the molecular weight and charge characteristics of MF.
Main Methods:
- Protease treatment to assess enzymatic susceptibility.
- Gel filtration chromatography (Sephadex, Bio-gel) for molecular weight estimation.
- Polyacrylamide gel electrophoresis (PAGE) for charge and mobility analysis.
- Isoelectric focusing (IEF) to determine isoelectric points.
Main Results:
- MF activity was significantly reduced by protease treatment, indicating a protein composition.
- Gel filtration suggested a molecular weight range of 20,000–30,000 daltons, with a peak at 25,000 daltons.
- Electrophoretic analysis revealed MF fractions with mobilities corresponding to alpha1- and alpha2-globulins and transferrin.
- Isoelectric focusing identified three MF fractions within the pH range of 4.5–8.3.
Conclusions:
- The mitogenic factor (MF) is likely a protein with a molecular weight between 20-30 kDa.
- MF exhibits heterogeneity in terms of charge and isoelectric point.
- These findings suggest potential functional heterogeneity within the MF produced by lymphocytes.