Rosette tests for T and B lymphocyte immunoglobulin.

B lymphocytes synthesize and then express in their surface membranes immunoglobulin (Ig) molecules which serve as antigen receptors. Although controversy surrounds the precise nature of antigen receptors in T lymphocytes, these receptor molecules react with certain anti-Ig reagents and are considered to be Ig-related. Antiglobulin rosette tests and in particular the mixed antiglobulin rosetting reaction (MARR) and the direct antiglobulin rosetting reaction (DARR) have special merit in demonstration of lymphocyte Ig and Ig-related surface determinants; these lest systems are reviewed and compared with more conventional direct binding methodology which uses free anti-Ig molecules to sensitize lymphocytess.