Lyophilized whole human melanoma cells stimulate human PBMC proliferation and enhance suppressive action of PBMC toward survival of the same malignant cell line in vitro

The goal of this work was to determine: a) do lyophilized human melanoma BG or Fem-X cells affect the proliferative capacity of normal human periphera l blood mononuclear cells (PBMC) and b) does the PBMC six-days preincubatio n in nutrient medium with FBS with, or without lyophilized human melanoma B G or Fem-x cells, affect their suppressive action on the survival of the sa me malignant cell line in vitro. In the aim to avoid any stimulating effect of FBS, other group of experiments were done in nutrient medium with human AB serum in order to determine: c) does the PBMC six-day-preincubation wit h lyophilized human melanoma BG or Fem-x cells affect their antiproliferati ve action on the corresponding malignant cell line in vitro and d) does the PBMC six-day preincubation with lyophilized normal PBMC, obtained from hea lthy volunteer las a source of allogenous, but not of tumor antigens), affe ct their suppressive action on the survival of both melanoma BG and Fem-x c ell lines in vitro. Results obtained in the presence of FBS in nutrient medium, showed that lyo philized BG cells induced a proliferation of the healthy PBMC, depending on the number of stimulating lyophilized cells. Lyophilized Fem-x cells induc ed healthy PBMC proliferation in lesser degree than lyophilized BG cells. T his stimulation was almost constant, not dependent on the number of stimula ting lyophilized Fem-x cells. Six-day stimulation in vitro by both lyophili zed melanoma cells enhanced the suppressive action of PBMC on the survival of the corresponding malignant cell line. Experiments done in nutrient medium with normal human AB serum showed that six-day stimulation with lyophilized melanoma cells enhanced, again, the su ppressive action of PBMC on the survival of the corresponding malignant cel l line. Contrary, six day preincubation of normal PBMC with the lyophilized healthy PBMC (obtained from other healthy person) inhibited their suppress ive action on the survival of both malignant cell lines in vitro.