Exposure of human peripheral blood mononuclear cells (PBMC) to hydrostaticpressure increases their proliferative response to phytohemagglutinin A (PHA) and anti-CD3 antibody

In the present study we show that a brief exposure of human PBMC to hydrost atic pressure (HyP) increased their proliferative response to PHA and anti- CD3 antibody, assessed by DNA synthesis. The effect of HyP was most promine nt at 400 atmospheres of HyP followed by 600 and 200 atmospheres. At any pr essure level, the highest effect of HyP was noted when employing PHA and an ti-CD3 antibody at 10(-2) dilution. When PBMC were exposed to 400 atmospher es HyP, maximal effect was achieved at 20 minutes of exposure. The highest effect of HyP on DNA synthesis was noted at 48 and 72 hours of incubation w ith PHA, when exposing cells to pressure for 20 minutes at 400 atmospheres. Exposure of PBMC under similar conditions for 40 minutes, caused an increa se in DNA synthesis only at 48 hours incubation with PHA. These results dem onstrate that exposure of human PBMC to HyP increases their proliferative r esponse to different polyclonal activators. The possible mechanisms involve d in this phenomenon are discussed.