This study examines the function of a novel B cell line (MIN6) enclosed in hybrid bioartificial pancreas with mesh-reinforced polyvinyl alcohol hydrogel tube (MRPT) or with improved, three-layer agarose microcapsules. MIN6 was established from insulinomas obtained by targeted expression of the simian virus 40 T-antigen gene in transgenic mice. MIN6 retains the ability to secrete insulin in response to physiological glucose concentrations. The MRPT and the three-layer agarose microcapsules, which were developed to act as an artificial pancreas, were readily permeated by insulin, glucose, and other nutrients. Both can immunoisolate enclosed MIN6 cells from the recipient's humoral and cellular immunosystems, which causes a xenogeneic rejection response. MIN6 cells (5.0 x 10(6) or 1.5 x 10(6)) were enclosed in MRPT or in a hundred three-layer microcapsules and subjected to an in vitro perifusion study or a static incubation study to observe the insulin release from each bioartificial pancreas in response to glucose stimulation. In vitro study revealed that the insulin secretion in response to 16.7 mM glucose stimulation was twice that with 3.3 mM glucose stimulation with both MRPT and the three-layer agarose microcapsules. The present study demonstrates that MIN6 effectively functions as a bioreactor for the hybrid bioartificial pancreas. The application of MIN6 cells to the hybrid bioartificial pancreas may offer a solution to the current serious dearth of organs.