Immunologic Specificity of Lymphocyte Cell Lines from Dogs Exposed to Beryllium Oxide

Abstract

We have reported that dogs exposed twice to aerosols of beryllium oxide (BeO) developed Be-specific immune responses within the lung, along with granulomatous and fibrotic lung lesions. To evaluate the specificity of the immune response, lymphocytes from lungs and blood of BeO-exposed dogs were co-cultured over an irradiated blood monocyte layer, alternately with interleukin 2 and BeSO₄. Resultant cell lines were then tested for their response to different metal cations, common canine recall antigens, and BeSO₄ in an in vitro cell proliferation assay. The cell lines responded to BeSO₄ in a dose-dependent fashion, with mean stimulation indices of 7, 58, 119, and 112 at concentrations of 0.01, 1.0, 10, and 100 μM BeSO₄ respectively. Cells not proliferate when incubated with ZnSO₄ or NiSO₄, or with canine distemper, leptospira, adenovirus 2, parvovirus, or parainfluenza antigens. Lymphocytes from normal vaccinated dogs proliferated markedly when cultured with these antigens. Cells from the cultured cell lines (91%) stained with Thy-1 (a pan T-cell marker) and 96% stained with DT2 (a helper T-cell marker). Furthermore, the Be-induced proliferative response was restricted by major histocompatibility (MHC) class II antigens. These data reinforce the premise that inhalation exposure of dogs to BeO produces lung lesions and MHC class II restricted immunologic responses mediated by Be-specific, helper T-Cells. These data further confirm the hypothesis that antigen localized to the lung results in the recruitment of T-cells to the lung, followed by localized antigen-specific, cell-mediated immune responses.