Mucin is a high molecular weight glycoprotein that plays an important role in protecting the gallbladder epithelium from the detergent effect of bile. However, it also participates in gallstone formation. There is little information about a possible relationship between gallbladder inflammation and mucin expression or gallbladder stones' characteristics. The aims of this study were to investigate stone characteristics and patterns of mucin expression in the gallbladder epithelium and bile of gallstone patients, in relation to inflammation. Gallbladder bile and tissue samples from 21 patients were obtained at surgery. Mucin content was evaluated by gel filtration on a Sepharose CL-4B column. Dot blot for bile mucin apoproteins and immunohistochemistry staining for gallbladder mucosal mucin apoproteins were performed with antibodies to MUC2, MUC3, MUC5AC, MUC5B and MUC6. Staining intensity score (0-3) was used for assessment of antigen expression and the level of inflammation. Gallstone cholesterol content was determined in 16 patients. MUC 5AC and MUC 5B were demonstrated in 95.4 and 100% of gallbladder bile samples, respectively. Immunohistochemistry staining with antibodies to MUC 2, MUC 3, MUC 5AC, MUC 5B and MUC 6 were positive in 0, 100, 85.7, 100 and 95.4% of the gallbladder mucosal samples, respectively. Pigmented brown stones were associated with a higher level of gallbladder inflammation. Mucin species expressed in gallbladder epithelium are MUC3, MUC5AC, MUC5B and MUC6. MUC5AC and MUC5B are secreted into bile. Inflammation of the gallbladder is accompanied by a higher level of MUC5AC expression and is associated with pigmented brown stones.

BAT is a monoclonal antibody (mAb) produced against membranes of a human Burkitt lymphoma cell line (Daudi) that was selected for its ability to stimulate lymphocyte proliferation. BAT manifests anti-tumor properties in mice bearing a variety of murine tumors. BAT also induced regression of human tumors inoculated into SCID mice that had been engrafted with human lymphocytes. The anti-tumor activity of BAT was related to its immune stimulatory properties. Previous data indicated that T lymphocytes and NK cells mediate in vivo the anti-tumor activity. In order to define the primary target cell for BAT stimulatory activity, the in vitro stimulatory effect of BAT on purified lymphocyte subpopulations was investigated. Human CD4(+), CD8(+) T cells and CD56(+) NK cells were purified and their in vitro response to BAT was investigated. Results indicate that BAT selectively stimulated CD4(+) cells as assessed by proliferation and secretion of IFN-gamma. FACS analysis has also revealed a selective increase in BAT antigen on CD4(+) T cells that were cultured with BAT antibody. The effector cells that mediate BAT-induced tumor eradication may, however, be distinct from those that serve as the primary cellular target of the antibody. Cytokines such as IFN-gamma that are produced by CD4(+) cells may be involved in activation of additional cell types that may be involved in tumor destruction.

No abstract