Increased stability of E-rosettes and restricted capping of sheep erythrocytes by lymphocytes of aged humans.

The processes of E-rosette dissociation and sheep red blood cell (SRBC) capping provide simple assays for studying age-related changes in membrane dynamics of T-lymphocytes. After incubation at 4 degrees C, no significant difference is observed between young-adult and elderly subjects, either in the number of rosette-forming-cells (E-RFC) or in the distribution of SRBC at the lymphocyte surface. However, when the E-RFC are incubated at 22 or 37 degrees C after resuspension, the rosettes disintegrate to a larger extent forming fewer morula-like structures and more caps in young donors. An inverse relationship is noted between the number of E-RFC and the percentage of capping cells, suggesting a role for the lateral movement of the SRBC receptors in the dissociation process. In the elderly, rosette disintegration seems to be related only to the random release of SRBC. It is speculated that this increased stability of the E-rosettes represents some locking of the T-lymphocyte membrane receptors, which could alter the transduction of cell-cell signals.