Lysozyme activity in gastrointestinal and lymphoreticular tissues of rabbits genetically deficient in lysozyme

Lysozyme activities in gastrointestinal and lymphoreticular tissues and in macrophage culture products of normal and genetically lysozyme-deficient rabbits were measured and compared. The supernatants of homogenates of 18 gastrointestinal and lymphoreticular tissues were assayed for lysozyme. In the gastrointestinal tract, there were no major differences in lysozyme activities between the two groups of rabbits. Ascending colon and orad gastrointestinal tissues had low activities, whereas descending colon and rectum had very high lysozyme activities in both types of rabbits. In the lymphoreticular tissues, lysozyme-deficient rabbits had graded lysozyme deficiencies: slight or no deficiency was present in thymus, partial deficiency in gut-associated lymphoid tissues, and near total deficiencies in secondary lymphoid tissues and bone marrow. Both macrophage culture cells and fluids from lysozyme-deficient rabbits were completely deficient in lysozyme. The results indicate that in the lysozyme-deficient rabbits there is tissue-specific lysozyme activity expressed and when considered along with other observations suggest that the lysozyme-deficient condition may be due to a deficiency of an isozyme or isozymes of lysozyme.