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B-cell stimulation by T-cell-secreted proteoglycan.
1Guthrie Research Institute, Sayre, Pennsylvania 18840-1692.
Cellular Immunology
|December 1, 1987
Summary
Researchers identified a T-cell proteoglycan fraction (T-PGF) that stimulates B-cell activity. This T-PGF contains chondroitin sulfate proteoglycan (CSPG), suggesting CSPG is the primary B-cell stimulatory factor.
Area of Science:
- Immunology
- Biochemistry
Background:
- A B-cell stimulatory factor, T-cell proteoglycan fraction (T-PGF), composed of chondroitin sulfate proteoglycan (CSPG) and a 70- to 75-kDa protein, is secreted by T cells.
- The precise component responsible for T-PGF's B-cell stimulatory activity requires further characterization.
Purpose of the Study:
- To elucidate the role of CSPG within T-PGF in mediating B-cell stimulation.
- To confirm the stability and biochemical properties of the T-PGF-associated B-cell stimulatory activity.
Main Methods:
- Isolation and purification of T-PGF from a T-cell hybridoma (T14).
- Biochemical characterization using Sephacryl S-200 chromatography and CsCl density gradients.
- Assessment of B-cell stimulation and B-cell proliferation (PFC formation) in low-density (activated) and high-density (resting) B-cell fractions.
Main Results:
- The association between B-cell stimulatory activity and CSPG within T-PGF was found to be stable.
- T-PGF and CSPG comigrated under high salt and CsCl gradient conditions, indicating a strong complex.
- T-PGF stimulated B-cell activity, with enhanced relative plaque-forming cell (PFC) formation observed in resting B-cell fractions.
Conclusions:
- The B-cell stimulatory activity of T-PGF is primarily attributed to its chondroitin sulfate proteoglycan component.
- CSPG plays a significant role in modulating B-cell responses, particularly in resting B cells.