Abstract
Inflammatory responses, which were induced in the peritoneal cavity of mice by a variety of stimuli, produced an enhanced immune response to sheep erythrocytes when the antigen was introduced at an early stage of the inflammatory responses. The enhancement could be reproduced when early peritoneal exudate cells, consisting mostly of neutrophils, were adaptively transferred at the same time as antigen. The neutrophils were shown to produce a lymphocyte-activating soluble factorin vivaandin vitro. The PMN-derived factor produced the enhancement of several lymphocyte functions, including T-cell proliferative response, primary plaque forming cell response and allo-reactive killer T cell response.
The PMN factorper sewas non-mitogenic and exhibited maximum potentiation of T lymphocyte response when added within 3 hr of antigen or mitogen stimulation. Mitogen-stimulated, but not nonstimulated thymocytes absorbed PMN factor activity.125I-labelled factor binding to stimulated thymocytes was proved. Thus, it is suggested that an acceptor site for PMN factor may be generated on the thymocyte surface only after mitogen stimulation.
The PMN factor was composed of two isoelectrophoretically distinct factors, a cationic (pI 9.8) and a neutral (pI 5.4) PMN factor. The two purified, 125I-labelled PMN factors were homogeneous on SDS-PAGE. Their molecular weights were calculated to be 19, 000 for cationic-and for 21, 000 neutral PMN factor by Svedberg equation.
