Inherited lysozyme deficiency in rabbits. The absence of a primary isozyme of lysozyme as the cause of the condition.

Lysozyme from normal and genetically lysozyme-deficient rabbits was extracted from three types of tissue: leukocytic (bone marrow), lymphoepithelial (thymus and appendix), and gastrointestinal (colon). Extracts were analyzed by electrophoretic, chromatographic, and kinetic techniques. Identification of at least two isozymes of rabbit lysozyme was made with these techniques. The distribution of the isozymes was tissue specific. Leukocytic and gastrointestinal isozymes were clearly distinguished, and a possible lymphoepithelial isozyme that resembled the gastrointestinal isozyme electrophoretically and chromatographically but not kinetically was identified. Mutant, lysozyme-deficient rabbits lacked completely a detectable leukocytic isozyme but had gastrointestinal and lymphoepithelial isozyme(s) indistinguishable from those of normal rabbits. By electrophoretic methods, the mutant rabbits were demonstrated to lack a protein band corresponding to that of the leukocytic isozyme of lysozyme from normal rabbits. These observations considered collectively were interpreted as evidence that at least two primary isozymes of lysozyme are present in rabbits and that inherited lysozyme deficiency in rabbits is caused by the absence of a single primary isozyme.