Immunoglobulins in stimulated tears of dogs

Immunoelectrophoresis and single radial immunodiffusion were used to identify and measure tear immunoglobulin concentrations in 50 healthy dogs. Immunoglobulin A and IgG were detected in all samples analyzed, whereas IgM was not detected in any sample. Mean IgA concentration was 25.28 +/- 1.9 mg/dl, adult dogs (> 18 months) having significantly higher mean value. The IgA concentration related to age had significant (P < 0.006) positive correlation; mean IgG concentration was 23.10 +/- 1.72 mg/dl. Linear correlation analysis revealed significant (P < 0.0007) correlation coefficient between tear total protein and IgA concentrations. The IgA and IgG concentrations also were significantly (P < 0.0001) correlated when expressed as milligrams per 100 mg of protein. Relation with sex was not established for either immunoglobulin.