LTBR-Ig enhanced the volume of tear-fluid secreted by lacrimal glands. Mice were treated from age 8 to 16 weeks with LTBR-Ig (circles), with MOPC-21 control antibody (triangles), or were left untreated (squares). The amount of tear fluid secreted for each eye of each mouse was determined by insertion of a Zone-Quick phenol impregnated thread under the eyelid at the medial canthus. The length of thread wetted by capillary action in 30 seconds was measured and plotted (a). The amount of tear fluid secreted was determined at age 12 weeks (after 4 weeks of treatment) and at 16 weeks of age (after 8 weeks of treatment), as indicated on each graph in (a). The rate of tear fluid secretion was also determined in the presence of pharmacologic stimulation. In a separate experiment, after 8 week treatments as indicated, each mouse was injected with pilocarpine to maximally stimulate tear fluid secretion, and after 5 minutes, the amount of tear fluid secreted by each eye during the next 10 minutes was measured by wetting of a Zone-Quick thread placed under the lid (b). Statistical analysis was by the two-tailed Student's test. P*< 0.05; P**< 0.01; P*** < 0.001. This type of experiment was performed four times. LTBR-Ig; lymphotoxin-beta receptor-mouse immunoglobulin (Fc) chimeric inhibitor.