DECREASE OF INTRACELLULAR FLUORESCEIN FLUORESCENCE POLARIZATION (IFFP) IN HUMAN PERIPHERAL-BLOOD LYMPHOCYTES UNDERGOING STIMULATION WITH PHYTOHEMAGGLUTININ (PHA), CONCANAVALIN-A (CONA), POKEWEED MITOGEN (PWM) AND ANTI-CD3 ANTIBODY

In the present study we describe the induction of changes in intracell ular fluorescein fluorescence polarization (IFFP) in lymphocytes under going activation with a variety of stimulants. These stimulants includ ed the lectins phytohaemagglutinin (PHA), concanavalin (ConA), pokewee d mitogen (PWM) and anti-CD3 antibody. Changes in IFFP were detected i n individual cells using the Cellscan apparatus. Our results show that by employing mitogenic concentrations of PHA, as revealed in a [H-3]- thymidine incorporation assay, a decrease in the IFFP in human periphe ral blood lymphocytes (PBL) occurred within 40 min. ConA and anti-CD3 affected similarly IFFP, whereas PWM, a B lymphocyte lectin, had no ef fect on IFFP at the concentrations employed. Kinetic analysis revealed that changes in IFFP occurred within 20-40 min after exposure to the stimulants and lasted for 24 h. Our results show that stimulants which activate CD3(+) lymphocytes caused immediate changes in IFFP, in an e nriched population of human PBL. The possible mechanisms involved in I FFP modulation following exposure to selected stimulants are discussed .