ROLES OF BETA-GALACTOSIDASE OF B-LYMPHOCYTES AND SIALIDASE OF T-LYMPHOCYTES IN INFLAMMATION-PRIMED ACTIVATION OF MACROPHAGES

The outer surface of mouse B lymphocytes carries constitutive and indu cible beta-galactosidase isozymes. A brief (30 min) treatment of B lym phocytes with lysophosphatidylcholine (lyso-Pc) immediately induced an approximate 3-fold higher beta-galactosidase activity than the consti tutive isozyme of untreated B lymphocytes. Thus, the lyso-Pc-inducible isozyme is not a de novo enzyme. Outer surface of mouse T lymphocytes carries constitutive (non-Neu-1) and inducible (Neu-1) sialidase isoz ymes. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and th e Neu-1 sialidase of T lymphocytes were required for conversion of vit amin D-3-binding protein (Gc protein) to a potent macrophage activatin g factor. This enzymatic generation of the macrophage activating facto r was enzyme-associated receptors.