Dermal fibroblasts from patients with systemic sclerosis (SSc) bound a much greater number of T lymphocytes than did normal dermal fibroblasts. Monoclonal antibodies (MAb) against classes I and I1 antigens of the major histocompatibility complex (MHC) and their receptors, CDS and CD4, had no effect on T cell interaction with SSc and normal cells, while MAb against lymphocyte function-associated antigen type 3 (LFA-3) and CD2 both strongly inhibited lymphocyte attachment. MAb against intercellular adhesion molecule type 1 (ICAM-1) and LFA-1 also prevented binding of T lymphocytes, but had a more marked effect on adhesion to SSc fibroblasts than to normal fibroblasts; they also completely abolished the increased binding to Submitted for publication November 6, 1990; accepted in revised form April 2, 1991. fibroblasts treated with interleukin-la, tumor necrosis factor a, and interferon-?. No difference was found in the proportion of normal and SSc fibroblasts that expressed MHC classes I and I1 and LFA-3, but more SSc cells expressed ICAM-1, and at a higher level, than did normal fibroblasts. These results show that cultured SSc cells have elevated binding to T lymphocytes, which possibly results from expansion of a subset of fibroblasts that produces high levels of ICAM-1. Scleroderma (systemic sclerosis; SSc) is a multisystemic connective tissue disease characterized by microvascular obliteration and increased deposition of collagen resulting in fibrotic lesions (1-3). Although the pathogenesis of SSc is still uncertain, this complicated disorder involves inflammation, autoimmune features, vascular damage, activation of fibroblasts, and complex interactions between cells and components of the extracellular matrix (4-6).Studies of SSc have focused mainly on the altered metabolic activities of several types of cell that have been implicated in the disease process and the expression of specific surface receptors (7). Fibroblasts from affected areas of the skin of patients with SSc have been shown to produce greater amounts of types I and I11 collagen and other matrix proteins than normal fibroblasts (8-11) and to have higher levels of messenger RNA (mRNA) of these components (12,13). Recent in situ hybridization experiments showed that the increased amounts of collagen mRNA were expressed by only a subpopulation of the fibroblasts that were often localized adjacent to dermal blood vessels within the affected skin (14,15). These were frequently surrounded by mononuclear cells, a
Serum and yolks from commercial flocks and from hens exposed to Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and Mycoplasma gallisepticum (MG) were tested for immunoglobulin G antibody by the enzyme-linked immunosorbent assay (ELISA) and the hemagglutination-inhibition (HI) test. Yolks prepared by chloroform extraction and low-speed centrifugation performed well in the serological tests used and were a suitable alternative to serum for antibody determination by the ELISA for NDV, IBV, and MG and by HI test for NDV.
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