Immunologic identification of lymphocyte subsets in experimental murine myocarditis with encephalomyocarditis virus. Different kinetics of lymphocyte subsets between the heart and the peripheral blood, and significance of Thy 1.2+ (pan T) and Lyt 1+, 23+ (immature T) subsets in the development of myocarditis.

Abstract

To clarify the immune mechanism in myocarditis, immunofluorescence techniques with laser flow cytometry were used to examine serial changes in lymphocyte subsets in the heart, spleen, and peripheral blood of DBA/2 and BALB/c mice inoculated with encephalomyocarditis virus (Experiment I). B cells were identified by staining with fluorescein isothiocyanate-labelled rabbit anti-mouse immunoglobulin. T-cell subsets were identified with rat anti-Thy 1.2, and nonpolymorphic Lyt 1 and Lyt 2 monoclonal antibodies plus fluorescein isothiocyanate-labelled anti-mouse immunoglobulin. On days 7 and 14 postinfection, the percentage of Thy 1.2+ (pan T) cells in both strains had decreased in the peripheral blood; B cells showed no significant changes throughout the entire period. On the other hand, Thy 1.2+ (pan T) and Lyt 1+, 23+ (precursor and immature) T cells appeared to occupy the major portion of the myocardium on days 7 and 14 when congestive heart failure developed. To confirm this, serial immunohistologic studies (immunoperoxidase staining) of the hearts of DBA/2 and BALB/c mice with encephalomyocarditis virus-induced myocarditis were performed (Experiment II). In Experiment II, most of the stained cells in the hearts of both strains were Thy 1.2 positive and Lyt 1 and Lyt 2 positive on days 7 and 14. Thus, Experiments I and II demonstrated that lymphocytes at the site of inflammation in acute viral myocarditis carried antigenic markers that differed from those of peripheral lymphocytes and suggested that Thy 1.2+ (pan T) cells, especially the Lyt 1+, 23+ subset (immature T cells and T-cell subset precursors) were involved in the development of myocarditis in these animals.

A short‐term extremely low frequency electromagnetic field exposure increases circulating leukocyte numbers and affects HPA‐axis signaling in mice

“…Within the selected mononuclear cell population, we showed a relative increase in circulating CD4+ T cells after 1‐week exposure. Percentage of lymphocytes (CD3 or CD19 positive) was relatively low [Kishimoto et al, 1987]. This suggests that a relative large number of monocytes and NK cells were present in this gated mononuclear cell fraction.…”

Enhanced Production of Macrophage Inflammatory Protein 2 (MIP-2) by In Vitro and In Vivo Infections with Encephalomyocarditis Virus and Modulation of Myocarditis with an Antibody against MIP-2

“…The myocarditic strain of EMC virus was used. Virus stock was prepared as described previously (8,10,12) and stored at Ϫ80°C until it was diluted for use. Virus titers in the heart were determined by plaque formation on Vero (African green monkey kidney) cells.…”

“…Two sections were analyzed for each sample, and each score was derived from the mean of the two sections. Some portions of the heart were snap frozen, mounted with ornithine carbamyltransferase compound, and examined immunohistologically as previously described (10,12). Briefly, an indirect horseradish immunoperoxidase technique was used, and horseradish peroxidase activity was visualized with DAB as the chromogen.…”

“…Four hearts were examined in each group. We calculated the percentage of positive-stained cells, as previously described (10,12).…”

“…Since monocyte migration is a crucial step in the development of myocarditis, we investigated the behavior of MIP-2 in encephalomyocarditis (EMC) virus infection both in vitro and in vivo and the effects of an anti-MIP-2 antibody on murine viral myocarditis (8,10,12).…”