SummaryWestern blot analysis showed that a monoclonal antibody against recombinant mouse CD14 (mCD14), designated rmC5-3, specifically reacted with mouse macrophage cell line J774, but not myeloma cell line NS1. Fluorographic and immunocytochemical analysis demonstrated specific binding of rmC5-3 with mouse resident macrophages, inflammatory monocytes and neutrophils, and macrophage cell lines. Immunohistochemical staining using rmC5-3 showed that CD14-positive Kupffer cells (KC) were small in number in the liver in nonstimulated mice. The number of stained KC, which were rich in the midzonal and periportal regions, gradually increased with time after intraperitoneal injection of lipopolysaccharide (LPS), peaked 6 h after injection, and returned to normal by 20 h after injection. Staining intensity over time was proportional to the number ofKC. A slight increase in mCD14 expression was observed in peritoneal macrophages 2 h after LPS administration in vivo using flow cytometric analysis, mCD14 mRNA became detectable at 1 h after the intraperitoneal injection of LPS (20 gg/mice), and the level dramatically increased with time, peaking at 3 h, and sharply dropped at 6 h. The resident peritoneal macrophages demonstrated a constitutively high mCD14 mRNA expression, which slightly increased 2 h after LPS (100 ng/ml) stimulation in vitro. The level of mCD14 expression in macrophages did not increase after intraperitoneal injection of LPS (20 gg/mice).

We isolated the human osteopontin (hOP) gene and the 5' upstream region, and analysed its exon-intron structure and potential regulatory sequences of the promoter region in comparison with those of the mouse and porcine gene. The coding sequence is split into 7 exons which are similar to those of the mouse gene, although the hOP gene is longer than the mouse gene. The difference in length is mainly due to variations in intron 3, which is approximately 2.7-fold longer than that of the mouse OP gene. The 5' upstream region of the hOP, which is highly conserved up to nucleotide -250, contains a number of potential cis regulatory consensus sequences. A series of sequentially 5'-deleted chimeric clones was tested for the ability to stimulate chloramphenicol acetyltransferase (CAT). Initial CAT analysis demonstrated that nucleotides at positions -474 to -270, -124 to -80, and -55 to -39 contained cis-acting enhancing sequences in a human monocyte cell line, SCC-3, although the -124 to -80 region was much more active than other regions. Deletion of the sequences between -474 and -270 localized this cis region to the sequence at positions -439 to -410, whereas the deletion between -124 to -80 localized the regions to -124 to -115, and -94 to -80. Gel-shift analysis using as probes synthesized double-stranded DNA corresponding to the 10 and 15 bp region at positions -124 to -115 and -94 to -80 respectively revealed that each probe formed a major band complexed with nuclear proteins prepared from SCC-3 cells.

cDNA clones which strongly hybridized with a 3.1 kb mRNA from mouse macrophages and macrophage cell lines and weakly with mRNA from P815 but not from a variety of other cell lines and tissues were isolated from cDNA libraries constructed using mRNA from murine macrophage cell lines and peritoneal macrophages. Treatment of a macrophage cell line with macrophage stimulators significantly enhanced transcription of the mRNA. Sequencing analysis of these clones demonstrated that the cDNA consisted of 3036 bp insert containing a 2478 bp open reading frame followed by a 538 bp 3' untranslated region. The amino acid sequence, deduced from the nucleotide sequence of the cDNA, predicted a protein containing a signal peptide, an extracellular region, a transmembrane domain, and a cytoplasmic tail. The extracellular region had five putative N-glycosylation sites and a cysteine-rich domain, whereas the cytoplasmic region consisted of a proline-rich amino acid sequence significantly similar to CD2. SDS-PAGE and NEPHGE SDS-PAGE analysis of the immunoprecipitated membrane of the macrophage cell lines prepared by using rabbit anti-MS2 peptide antibody raised against a synthetic peptide preparation relative to a hydrophilic region of the MS2 amino acid sequence confirmed that MS2 protein is a cross-linked protein having approximate molecular sizes of 89 kd and pl 6.5-7.0. These results show that MS2 protein is a novel cell surface antigen expressed mainly in monocytic lineages.

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For the immunohistochemical detection of immunoglobulin (Ig) light chain amyloidosis on formalin-fixed, paraffin-embedded tissue sections, we prepared polyclonal antibodies against synthetic peptides corresponding to positions 118-134 of Ig lambda light chain and positions 116-133 of Ig kappa light chain. Nineteen cases of systemic Ig lambda light chain amyloidosis (Alambda amyloidosis), 10 cases of systemic Ig kappa light chain amyloidosis (Akappa amyloidosis), one case of immunohistochemically unclassified systemic amyloidosis and five cases of localized Alambda amyloidosis were tested with these antibodies. Anti-lambda (118-134) antiserum and the affinity-purified antibody both reacted with 18 of the 19 cases of systemic Alambda amyloidosis and all cases of localized Alambda amyloidosis, although the immunoexpression was somewhat variable in intensity in different areas within the same specimen in both systemic and localized amyloidosis. The signal intensities in plasma cells and serum reacted for anti-lambda (118-134) antiserum were weaker than signals obtained with commercially available anti-Ig lambda light chain antibodies. Anti-kappa (116-133) antiserum and the affinity-purified antibody reacted with nine of the 10 cases of systemic Akappa amyloidosis. We conclude that these antibodies against synthetic peptides corresponding to the Ig light chain constant region are useful for the classification of amyloidosis on formalin-fixed, paraffin-embedded tissue sections.

We herein report that experimental murine amyloid A (AA) deposition is accelerated by oral administration of semipurified amyloid fibrils extracted from different species. Three groups of mice were treated with semipurified murine AA amyloid fibrils, semipurified bovine AA amyloid fibrils or semipurified human light chain-derived (A(lambda)) amyloid fibrils for 10 days. After 3 weeks, each mouse was subjected to inflammatory stimulation by subcutaneous injection with a mixture of complete Freund's adjuvant supplemented with Mycobacterium butyricum. The mice were killed on the third day after the inflammatory stimulation, and the spleen, liver, kidney and gastrointestinal tract were examined for amyloid deposits. Amyloid deposits were detected in 14 out of 15 mice treated with murine AA amyloid fibrils, 12 out of 15 mice treated with bovine AA amyloid fibrils and 11 out of 15 mice treated with human A(lambda) amyloid fibrils. No amyloid deposits were detected in control mice receiving the inflammatory stimulant alone or in amyloid fibril-treated mice without inflammatory stimulation. Our results suggest that AA amyloid deposition is accelerated by oral administration of semipurified amyloid fibrils when there is a concurrent inflammatory stimulation.

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The expression level of osteopontin (OPN) mRNA was found to be increased in a macrophage cell line in the presence of recombinant tumor necrosis factor-alpha (TNF-alpha). OPN mRNA level was also explored in the lungs of transgenic mice which were expressing TNF-alpha in type II pneumocytes, a condition leading to pulmonary alveolitis and progressive fibrosis. OPN mRNA was significantly increased in the lungs of these transgenic mice. In situ hybridization showed that it was localized mostly in alveolar macrophages. Since OPN can be induced in macrophages by TNF-alpha stimulation and since on the other hand osteopontin appears to decrease the level of nitric oxide synthase, and thus the production of nitric oxide, osteopontin might also indirectly have an antifibrotic effect. The role played by osteopontin in fibrotic lesions resulting from the release of TNF-alpha deserves further study, since it may be involved in the balance of opposite effects eventually leading to local tissue damage ending in fibrosis.