OX6-positive Cells Research Articles

A histological study on experimental autoimmune myocarditis with special reference to initiation of the disease and cardiac dendritic cells.

The precise mechanism of myosin-induced autoimmune myocarditis is unknown. The purpose of the present study was to define the immunohistological and ultrastructural characteristics of the infiltrating cells, especially in the initial phase of the myocarditis. It was demonstrated that OX6-positive dendritic cells first infiltrated the cardiocytes on day 13 after immunization. After day 17, OX6-positive cells, which possessed elongated irregular-shaped processes on the cell surface but contained few phago-lysosomes in the cytoplasm, were located at the margin of an inflammatory field and inserted their processes into the sarcoplasm of cardiocytes. The central portion of the inflammatory field was occupied by ED1-positive inflammatory macrophages, which were rich in phagosomes and which were in contact with degenerating cardiocytes. No evidence was obtained which suggested that lymphocytes directly injured the cardiocytes. These results demonstrated ultrastructural evidence that the type of infiltrating cell that first injures cardiocytes is the cardiac dendritic cell. Inflammatory macrophages thereafter serve as scavengers of degenerating cardiocytes.

Phenotypic characterization of resident macrophages in submandibular salivary glands of normal and isoproterenol-treated rats

Macrophages exert a major effect in the stimulation of lymphocytes and the modulation of immunological responses. To determine the presence and phenotypic distribution of the resident cells of the mononuclear phagocyte system in submandibular glands, frozen sections were prepared from five normal rats, and from six rats treated with 20 mg/kg isoproterenol/day for 10 days. A panel of six monoclonal antibodies was used to identify membrane markers associated primarily with circulatory monocytes (ED1), mature tissue macrophages (ED2), lymphoid macrophages (ED3), Ia antigen (OX6), CD5-positive T lymphocytes (OX19) and rat B lymphocytes (OX33). Cells identified by each monoclonal antibody were quantified by averaging the number of positive cells in 10 consecutive random high-power fields. ED2 cells (165 cells/field) were predominant in normal rat submandibular gland, followed by lower numbers of OX6-positive cells (18 cells/field). Cells positive for the remaining markers were also present in smaller amounts. In submandibular glands, treatment of rats with isoproterenol resulted in an increase in ED1-positive cells (from 2 to 39 cells/field), but also in substantial decreases in the number of cells positive for the remaining cell markers.-B cells were not detected in any of the submandibular glands examined. These data suggest that isoproterenol induces a mild inflammatory response within rat submandibular glands that is not observed in normal glands. This results in an increase in the relative number of infiltrating monocytes compared to the number of more mature tissue macrophages.