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Guinea pig lymphocyte-derived macrophage aggregation factor: its separation from macrophage migration inhibitory
Journal of Immunology (Baltimore, Md. : 1950)
|November 1, 1976
Summary
Guinea pig lymphocytes produce a large molecular weight factor that causes macrophage aggregation, distinct from macrophage migration inhibitory factor (MIF). This heat-stable factor, termed macrophage aggregation factor (MAF), is crucial for understanding immune responses.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Delayed hypersensitivity involves complex immune cell interactions.
- Lymphokines mediate various immune cell functions.
- Macrophage behavior is critical in immune responses.
Purpose of the Study:
- To identify the factor responsible for macrophage aggregation in vitro.
- To differentiate this factor from macrophage migration inhibitory factor (MIF).
- To characterize the properties of the macrophage aggregation factor (MAF).
Main Methods:
- In vitro culture of guinea pig lymphocytes sensitized to horse-radish peroxidase (HRPO).
- Separation of lymphocyte culture supernatant components using Sephadex G-150 gel filtration.
- Assessment of macrophage aggregation induced by fractionated supernatants.
- Enzymatic (trypsin) and heat stability assays.
Main Results:
- Lymphocytes produced a large molecular weight factor (>100,000 daltons) inducing macrophage aggregation.
- This macrophage aggregation factor (MAF) was separable from MIF.
- MAF demonstrated heat stability (56°C for 30 min) but was inactivated by trypsin.
- Macrophage aggregation was attributed to MAF, not MIF.
Conclusions:
- Macrophage aggregation in vitro is mediated by a distinct lymphokine, MAF.
- MAF is a heat-stable, trypsin-sensitive factor with a large molecular weight.
- These findings differentiate MAF from MIF, clarifying mechanisms of lymphokine action.