Antiserum to surface antigens as a marker for cultured rat lung endothelial cells (1)

Antibodies were developed in rabbits against an established line of endothelial cells from normal adult rat lung. Pre- and postimmunization sera were tested for antibody activity by the indirect immunofluorescence technique. Preimmunization serum failed to react with the endothelial cells, whereas the antibody titer of postimmunization serum from two rabbits was 1:512. Organ specificity and species specificity were assessed by absorbing the serum with packed dissociated cells from different organs of the rat and lung cells of other species. Only cells obtained from rat lung absorbed the antibodies completely. The antiserum showed some crossreactivity with the other cultured cells but the pattern of fluorescence was different. In the presence of complement the antiserum was found to be cytotoxic to cultured rat lung endothelial cells but not to the other crossreacting cells.