BACKGROUND: The role of interleukin-10 in graft acceptance and rejection was investigated by analysis of its messenger RNA expression within endomyocardial biopsy material from heart transplant recipients. METHODS: Forty-six biopsy specimens were analyzed from 19 patients (16 male, 3 female), with an age range of 15 to 62 years (mean = 47 years). Biopsy specimens were "snap" frozen in liquid nitrogen, and 10-microns thick sections were cut and postfixed in 4% paraformaldehyde. Messenger RNA for interleukin-10 was localized with nonradioactively (digoxigenin) labeled complementary DNA probes and detected immunoenzymatically with an antidigoxigenin polyclonal antibody. The histopathologic diagnosis of rejection was made according to the criteria of the Heart Rejection Study group. RESULTS: Interleukin-10 transcripts were detected in 12 of 36 rejecting biopsy specimens. None of the ten nonrejecting biopsy specimens were positive. Expression within the rejection infiltrate was more prominent in biopsy specimens from milder rejection episodes. By contrast, in biopsy specimens from moderate rejection, expression was mainly within areas of fibrosis. The expression of interleukin-10 transcripts did not relate to the number of previous rejection episodes nor to the histologic grade of the subsequent biopsy specimens. CONCLUSIONS: This study emphasizes the importance of in situ techniques in localizing cytokine expression in relation to tissue structure and suggests that interleukin-10 may serve a function in the immune regulation of the infiltrate at sites of inflammation, rather than in immune suppression of the rejection process. Further study is necessary to elucidate the precise role of interleukin-10 in transplantation in relation to the overall profile of cytokine expression within the rejection infiltrate.

Adolescent↗

PubMedDate not supplied

The interactions of protein inhibitors with tumour proteases studied in solution and immobilised on cell surfaces in frozen sections.

The cell surface protease guanidinobenzoatase (GB) has been purified from human colonic and lung carcinoma tissue by an affinity step involving the binding of the enzyme either onto fibrin fibrils or onto agmatine-sepharose. The inhibitor protein (I) was extracted from the cytoplasm of tumour cells and isolated by an affinity step involving the binding of I to GB on the surface of cultured carcinoma cells. The interaction of GB and I in solution was followed by kinetic studies employing the release of the fluorescent 4-methylumbelliferone (MU) from the synthetic substrate 4-methylumbelliferyl-p-guanidinobenzoate (MUGB). The interaction of soluble I with membrane bound GB was followed by using the yellow fluorescent probe 9-aminoacridine (9AA) which binds to active GB but not to GB-I. The results of these studies demonstrated the presence of isoenzymic froms of GB which were recognized specifically by their appropriate isoinhibitor, isolated from the appropriate cell type. This high degree of selectivity suggests a cell specific regulatory role for the inhibitors and the possibility that they might be used for the delivery of cytotoxic molecules to the surface of specific types of tumour cells.

Carboxylic Ester Hydrolases↗

PubMedDate not supplied

The diagnosis of pleural disease.

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Asbestos↗