EBV-inducing factor from platelets exhibits growth-promoting activity for NIH 3T3 cells

Area of Science:

• Biochemistry
• Cell Biology
• Virology

Background:

• Epstein-Barr virus (EBV) is a human herpesvirus associated with various diseases.
• Platelets are known to contain various growth factors and signaling molecules.

Purpose of the Study:

• To purify and characterize a factor from serum and platelets with Epstein-Barr virus (EBV)-indicating activity.
• To investigate the biological activities of the purified factor, specifically its growth-promoting effects on NIH 3T3 cells.

Main Methods:

• Purification of Epstein-Barr virus-indicating factor (EIF) from serum and platelets.
• Assay of growth-promoting activity on NIH 3T3 cells in platelet-poor plasma.
• Gel chromatography and SDS-gel electrophoresis to assess molecular properties.
• Comparison of EIF activity with platelet-derived growth factor (PDGF) using biological and biochemical assays.

Main Results:

• Highly purified platelet EIF demonstrated growth-promoting activity for NIH 3T3 cells.
• Both EBV-inducing and growth-promoting activities co-eluted and co-migrated, indicating they reside on the same molecule.
• EIF required a pH shock for full activity and acted in a similar concentration range for both activities.
• EIF's growth-promoting activity was biochemically and biologically distinct from PDGF, and not inhibited by anti-PDGF antibodies.

Conclusions:

• A single molecule, EIF, possesses both EBV-indicating and growth-promoting activities.
• EIF represents a novel growth factor with distinct properties differentiating it from PDGF.
• Further research into EIF may elucidate its role in EBV-associated processes and cell proliferation.