Abstract
Diminished rosetting capacity of T cells is a well-known phenomenon in Hodgkin's disease, and inhibitors of E rosette formation have been reported to be present in the plasma of patients with Hodgkin's disease. The cell line L428, representing an in vitro counterpart of Hodgkin and Sternberg-Reed cells, could be shown to release a factor capable of suppressing the binding of sheep red blood cells (SRBC) to normal peripheral-blood T lymphocytes or to a T-cell line (L735). At maximally effective concentrations, RIF (rosette inhibiting factor) inhibited T lymphocyte rosetting by approximately 40% (mean from 184 healthy controls). The diminished E rosetting of T lymphocytes from Hodgkin's patients was not further suppressed by added RIF. This factor inhibited binding of SRBC to their target cells at 37 degrees C but not at 4 degrees C. The factor could be stored lyophilized at -20 degrees C and was stable at 56 degrees C (30 minutes). RIF was inactive below pH 6 and above pH 9 or after trypsin digestion. Purification by affinity, ion exchange, and molecular sieve chromatography showed activity peaks at 12.5 Kd, 25 Kd, 50 Kd, and 100 Kd.
L428 cells derived from Hodgkin's disease produce E rosette-inhibiting factor