Antiproliferative activity of conditioned medium from lymphocytes of neuroblastoma (NB) patient and inhibition with NB serum

Neuroblastoma (NB) is a pediatric malignancy and results in high mortality rate. Cellular immunity has been shown to play an important role in killing tumors 'in vitro'. Human lymphocytes were activated in vitro with phytohae magglutinin (PHA) and the effect of supernatants collected at 24, 48, 72 an d 96 h were tested on proliferation of human NE cell line-SK-N-MC and gliom a cell line U87-MG. The SK-N-MC cells were observed to be more susceptible to the supernatants compared to U87-MG with higher inhibition of proliferat ion as evaluated by [H-3]thymidine incorporation (P < 0.05 for 24 and 72 h and P < 0.0005 for 48 and 96 h). Conditioned medium from lymphocytes of NE patient collected at 48 and 96 h after activation inhibited proliferation ( P < 0.005) of SK-N-MC cells. The presence of serum from NE patient decrease d the antiproliferative activity of supernatants from normal lymphocytes an d NE patient's autologous lymphocytes (P < 0.01). This preliminary data dem onstrates the capability of the activation of lymphocytes from NE patient u ndergoing aggressive multiagent chemotherapy and controlling proliferation of tumor cells on one hand and the role of serum from NE patient in abrogat ing to a certain extent the effect of activated immune cells thereby protec ting tumor cells, on the other hand. Both these aspects need to considered with equal importance to study mechanisms in designing strategies for immun e therapies. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.