Proteinases in pathology. Usefulness of histochemical methods

Abstract

The usefulness of optimized and newly elaborated histochemical methods for proteinases is illustrated on two selected substances. DAP IV (Gly-Pro-MNA,FBB,pH 7.2) was discovered in 39% and DAP II (Lys-Ala-MNA,FBB,pH 5.5) in 60% of the lymphocytes of human peripheral blood (ly). The reaction product of such ly differs in quality and quantity. On the ultrastructural level, the reaction product of DAP IV (Gly-Pro-MNA,HNF) was found in cell membranes and lysosomes. Enzyme activity in other areas was probably suppressed during the preparation procedure. Although the number of ly revealed with Lys-Pro-MNA and Phe-Pro-MNA at pH 5.5 and with Lys-Pro-MNA at pH 7.2 is high, these substrates do not distinctly discriminate DAP IV and DAP II. DAP IV occurs exclusively in T lymphocytes. The number of DAP IV-positive ly was not decreased in patients with myelofibrosis, plasmacytoma, chronic granulocytic leukemia, or tricholeukemia. It was, however, greatly reduced in chronic lymphatic leukemia (CLL). In patients with malignant lymphomas other than CLL, ly presence is related to the stage of the disease. Decreased values indicate a more severe stage or a relapse. In the majority of patients with gastric cancer DAP IV-positive ly were decreased. They were normal or increased in patients with peptic ulcer. The assessment of the number of DAP IV-positive ly is a simple method that provides information regarding the condition of patients with malignant lymphomas and gastric carcinoma. Neutrophilic leukocytes and their precursors, and to a lesser extent monocytes, are revealed when N-acetyl-Met-I-naphthyl ester (Ac-Met-N) is used as substrate. Membrane-bound lysosomal and cytosol proteinases were investigated together with disaccharidases in jejunal biopsies of patients with malabsorption syndrome. Activities of all enzymes were affected in patients with celiac disease. According to their impairment enzymes could be arranged: Lactase(L). trehalase (T), brush border endopeptidase (BBEP), gamma-glutamyl transferase (GGT), DAP IV, enzyme(s) cleaving Ac-Mer-N, aminopeptidase A, cytosol peptidases and aminopeptidase M. In the propria, DAP IV is decreased or absent, while GGT and, particularly, DAP II are increased. After a gluten-free diet, activities are restored in a reverse order. BBEP and GGT are useful as auxiliary parameters in the assessment of the damage or differentiation degree of enterocytes. DAP IV is a sensitive indicator of the involvement of the propria.

Immunohistochemical localization of dipeptidyl peptidase IV in rat digestive organs.

“…Svenson et al (23) purified DPP IV from pig small intestinal brush border membrane. DPP IV activity has also been localized in situ on the brush border of enterocytes of the small intestines of some animals, including humans, by the use of histochemical methods (2,3,8). In the present study, it was revealed that DPP IV in the rat small intestine was restricted to the external surface of brush border membranes in the enterocytes, thus confirming previous studies.…”

Subcellular localization of dipeptidyl peptidase IV in rat kideny and small intestine.

“…Our results were in agreement with those of previous studies (2,3,5,7,9,10,16), and confirmed the evidence that DPP IV is a brush border membrane peptidase. Furthermore, using a pre-embedding peroxidase labeled antibody (Fab' fragments) technique, we were able to more precisely determine the subcellular localization of DPP IV in these organs.…”

Distribution of Dipeptidyl Peptidase IV in Patients with Chronic Tonsillitis

“…The second explanation may be the fact that the tonsils and peripheral blood of children have a greater number of activated lymphocytes than those of adults, especially CD4 ϩ and (16,18), which may be a source of the serum form of DPP IV. Indeed, Lojda (17) demonstrated that DPP IV activity occurs in 39% of peripheral blood lymphocytes and exclusively in T lymphocytes.…”

“…The enzymohistochemical determination of DPP IV activity in tonsillar tissue was performed according to the method of Lojda (17). Briefly, 4 mg of Gly-Pro-4-methoxy-␤-naphthylamide (Sigma, Germany) was dissolved in 500 l of N,N-dimethylformamide (ICN, OH).…”