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

Abstract

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 phytohaemagglutinin (PHA) and the effect of supernatants collected at 24, 48, 72 and 96 h were tested on proliferation of human NB cell line-SK-N-MC and glioma 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 proliferation as evaluated by [ 3H]thymidine incorporation ( P<0.05 for 24 and 72 h and P<0.0005 for 48 and 96 h). Conditioned medium from lymphocytes of NB patient collected at 48 and 96 h after activation inhibited proliferation ( P<0.005) of SK-N-MC cells. The presence of serum from NB patient decreased the antiproliferative activity of supernatants from normal lymphocytes and NB patient's autologous lymphocytes ( P<0.01). This preliminary data demonstrates the capability of the activation of lymphocytes from NB patient undergoing aggressive multiagent chemotherapy and controlling proliferation of tumor cells on one hand and the role of serum from NB patient in abrogating to a certain extent the effect of activated immune cells thereby protecting tumor cells, on the other hand. Both these aspects need to considered with equal importance to study mechanisms in designing strategies for immune therapies.