Lectin-induced thermostable SE-rosette (TSER) formation by human peripheral blood lymphocytes

Lectin-activated human peripheral blood lymphocytes were able to form thermostable rosettes with sheep red blood cells (SRBC). Capability to form thermostable rosettes (TSER) after lectin treatment was comparable in time kinetics and dose dependence to cell size distribution changes. Enhancement of TSER formation by human lymphocytes exposed to PHA and Con A, however, occurred before 3H-Thymidine incorporation could been registered. Lectin treatment of lymphocytes from 20 healthy donors for 48 hrs induced 49 +/- 4% (PHA), 33 +/- 5% (Con A), and 20 +/- 2% (PWM) thermostable rosette forming cells, whereas in unstimulated cultures were found 4 +/- 1%. Furthermore, thermostable rosette forming cells were enriched by gradient centrifugation and characterized as activated lymphocytes of T-origin by SE rosetting and binding studies with various monoclonal antibodies. It was shown that preparation of TSER forming cells after lectin activation makes it possible to enrich the fraction of lectin-stimulated T lymphocytes.