Inducing a humoral immune response to pancreatic cancer antigen

Abstract

Background: Patients with pancreatic carcinoma have a grim prognosis. Here, we examine the induction of an in vitro antibody response of human B cells to pancreatic carcinoma antigens.

Material and methods: Cells of five cultured pancreatic ductal adenocarcinoma lines were lysed and their plasma membrane fragments isolated in an aqueous two-phase-system. The plasma membrane fragments were then added to cultures of isolated peripheral blood mononuclear cells from healthy volunteers for 14 days to act as a tumor antigen. Also, we added combinations of IL-2, IL-4, IL-21, anti-CD40 mAb and varying protein concentrations of the plasma membrane fragments to these cultures. We then tested characteristics and binding of resulting IgG and IgM against aforementioned tumor plasma membrane fragments and their respective cells using ELISAs.

Results: The combination of IL-2, IL-4 and anti-CD40 mAb elicited IgM production showing significant binding (p<0.05) to plasma membrane fragments. PANC-1 antigen and the combination of IL-4, IL-21 and anti-CD40 mAb was able to produce a significant and specific IgG formation against PANC-1 plasma membrane fragments (p<0.05). Tumor antigen, interleukins and anti-CD40 mAb had a significant impact on the binding capacity of these antibodies (p<0.05). IgG binding pancreatic carcinoma cells was observed when the tumor antigen concentration was increased during stimulation (p<0.05). BxPC3 plasma membrane fragments showed inhibitory effects on IgG binding BxPC3 antigens (p<0.05).

Conclusions: A human anti-tumor antibody formation can be induced in vitro using PANC-1 antigens and B cell stimulating agents. This response has the potential to generate antibodies specific to PANC-1 antigens. PRéCIS: The concept presented is novel and a promising approach to eliciting a specific B cell response to tumor antigen. The method may prove useful in understanding and developing anti-tumor immunity.

Keywords: Antibodies; CD40; Cancer antigen; IL-21; IL-4; Pancreatic cancer.