Preparation and characterization of chicken intraepithelial leukocytes

Intraepithelial leukocytes (IELs) form an important component of the intestinal immune system. Several methods of preparing chicken IELs were compared for cell yield, cell populations, and functional activity against a natural killer (NK)-susceptible lymphoblastoid cell line (LSCC-RP9). In addition, an attempt was made to immortalize IELs by infection with reticuloendotheliosis virus (REV) for use in cell-trafficking studies. Intestinal fragments were incubated in 5 mM DL-dithiothreitol at 41 degrees C for 15 min followed by three 45 min incubations in 0.1 mM EDTA. Gentle shaking of the intestinal fragments every 5 min caused considerably less damage to the epithelial cell layer than slow stirring with a magnetic bar. The latter method yielded more cells, but these were not functionally active in the NK-cell assay. The more gentle method resulted in a lower cell yield, but these cells were able to lyse LSCC-RP9; the percentage of lymphocytes present was lower but these contained a higher proportion of large granular lymphocytes. Infection of IELs with REV did not immortalize these cells.