(1) Lymphoid cells of rabbits have been rosetted by the mixed antiglobulin reaction and simultaneously stained for immunoglobulin (Ig), using horse-radish peroxidase-labelled anti-IgG and prepared for electron-microscopic examination. The vast majority of rosetting cells (95%) were lymphocytes, and essentially all the lymphocytes which rosetted had membrane-staining for Ig. (2) Lymph-node cells from immunized rabbits rosetting via specific receptors with red cells carrying antigen were likewise stained for Ig and prepared for electron microscopy. The vast majority of rosetting cells were lymphocytes and lymphoblasts (except in one rabbit, where 15% of the cells were macrophages). Virtually all rosetting lymphoid cells were shown to have Ig membrane determinants, suggesting that receptors on all rosetting cells are structured with Ig. (3) Reconstructions of rosetted lymphocytes were made from serial electron micrographs to show the distribution of both surface Ig determinants and receptors. From these reconstructions, the distribution of Ig determinants was shown to be irregular. The sites of receptor combination with RBC almost invariably stained for Ig determinants. This correlation is consistent with the Ig nature of antigen receptors.
ASJC Scopus subject areas
- Immunology and Allergy