Transfer of antigen from macrophages to lymphocytes. II. Immunological significance of the transfer of lipopolysaccharide.

Abstract

The immunological significance of lipopolysaccharide (LPS) transfer from macrophage into lymphocytes was studied in an in vitro system in which the lymphocytes were incubated during 24–72 hours with macrophages which had previously ingested S. enteriditis LPS (during 1 hour). Our results show that the in vitro immune response to LPS requires co-operation of lymphocytes with macrophages. After 24–72 hours of contact of the lymphocytes with macrophages containing ingested antigen, we observed within lymphocyte population a time dependent increase of the number of LPS-binding cells. This result was obtained by means of two different methods: rosettes formation and autoradiography. Autoradiographies performed on thick and thin sections showed that after contact with macrophages which had ingested (14)C-LPS, most rosettes forming cells (RFC) exhibited radioactivity. All these findings strongly argue in favour of the idea that LPS transfer from macrophages to lymphocytes is highly relevant for specific antibody synthesis by lymphocytes.