Detection of lysozyme in llama, sheep, and cattle tears

Objective-To determine whether the tears of llamas, sheep, and cattle conta in lysozyme and compare lysozyme concentrations in tears among these specie s. Animals-40 llamas, 5 sheep, and 36 cattle. Procedure-Electrophoresis, western blot immunoassay for lysozyme, a spectro photometric assay to detect rear lysozyme by its ability to lyse a suspensi on of Micrococcus lysodeiticus, and a microtiter prate colorometric assay w ere performed. Results-A 13.6-kd protein band was detected by use of electrophoresis and w estern blot immunoassay in llama and sheep tears but not cattle tears. Resu lts of spectrophotometric assay suggested that llama and sheep tears had hi gh concentrations of lysozyme, whereas cattle tears had low concentrations. Results of the microtiter plate colorometric assay suggested that llama te ars had high concentrations of lysozyme, whereas concentrations in sheep an d cattle tears were lower. Conclusions and Clinical Relevance-Lysozyme concentrations in tears may var y among species and this variability may contribute to differing susceptibi lities to ocular diseases such as infectious keratoconjunctivitis.