An Interlaboratory Validation Study of the Improved Transformation Assay Employing Balb/c 3T3 Cells: Results of a Collaborative Study on the Two-stage Cell Transformation Assay by the Non-genotoxic Carcinogen Study Group

The Non-genotoxic Carcinogen Study Group of the Environmental Mutagen Society of Japan organised the first step of an interlaboratory validation study on an improved cell transformation assay employing Balb/c 3T3 A31-1-1 cells. Nineteen laboratories participated in this study. The modified transformation assay was evaluated for its responsiveness, its inter-laboratory reproducibility and its transferability. In this study, a mixture of Dulbecco's modified Eagle's medium and nutrient mixture F12, supplemented with insulin–transferrin– ethanolamine–sodium selenite and 2% fetal bovine serum (FBS) was used during the period of expression of transformed foci, intead of the usual minimum essential medium with 10% FBS. 20-Methylcholanthrene (MCA) and 12 -O-tetradecanoylphorbol-13-acetate (TPA) were selected as a prototype initiator and a tumour promoter, respectively. Two series of experiments were conducted. In the first series, the transformation activity of MCA was examined at various concentrations. In the absence of the promoting treatment with TPA, exposure to MCA only weakly induced transformed foci. In the presence of 0.1μg/ml TPA, all laboratories observed significant dose-dependent increases in the number of transformed foci with increasing MCA concentrations. In the second series of experiments, various concentrations of TPA were tested. In the absence of initiating treatment with MCA, exposure to TPA weakly induced transformed foci in about half of the laboratories. In the presence of 0.2μg/ml MCA, all the laboratories observed significant dose-dependent increases in the number of transformed foci with increasing TPA concentrations. The results from this study support the usefulness of this modified two-stage transformation assay with Balb/c 3T3 cells.

Application of the Improved BALB/c 3T3 Cell Transformation Assay to the Examination of the Initiating and Promoting Activities of Chemicals: The Second Inter-laboratory Collaborative Study by the Non-genotoxic Carcinogen Study Group of Japan

The Non-genotoxic Carcinogen Study Group in the Environmental Mutagen Society of Japan organised the second step of the inter-laboratory collaborative study on one-stage and two-stage cell transformation assays employing BALB/c 3T3 cells, with the objective of confirming whether the respective laboratories could independently produce results relevant to initiation or promotion. The method was modified to use a medium consisting of DMEM/F12 supplemented with 2% fetal bovine serum and a mixture of insulin, transferrin, ethanolamine and sodium selenite, at the stationary phase of cell growth. Seventeen laboratories collaborated in this study, and each chemical was tested by three to five laboratories. Comparison between the one-stage and two-stage assays revealed that the latter method would be beneficial in the screening of chemicals. In the test for initiating activity with the two-stage assay (post-treated with 0.1μg/ml 12- O-tetradecanoylphorbol-13-acetate), the relevant test laboratories all obtained positive results for benzo[ a]pyrene and methylmethane sulphonate, and negative results for phenanthrene. Of those laboratories assigned phenacetin for the initiation phase, two returned positive results and two returned negative results, where the latter laboratories tested up to one dose lower than the maximum dose used by the former laboratories. In the exploration of promoting activity with the two-stage assay (pretreated with 0.2μg/ml 3-methylcholanthrene), the relevant test laboratories obtained positive results for mezerein, sodium orthovanadate and TGF-β1, and negative results for anthralin, phenacetin and phorbol. Two results returned for phorbol 12,13-didecanoate were positive, but one result was negative — again, the maximum dose to achieve the latter result was lower than that which produced the former results. These results suggest that this modified assay method is relevant, reproducible and transferable, provided that dosing issues, such as the determination of the maximum dose, are adequately considered. The application of this two-stage assay for screening the initiating and promoting potential of chemicals is recommended for consideration by other research groups and regulatory authorities.

Application of lectin microarray to crude samples: differential glycan profiling of lec mutants

We recently developed a novel system for lectin microarray based on the evanescent-field fluorescence-detection principle, by which even weak lectin-oligosaccharide interactions are detectable without a washing procedure. For its practical application, cell glycan analysis was performed for Chinese hamster ovary (CHO) cells and their glycan profile was compared with those of their glycosylation-defective Lec mutants. Each of the cell surface extracts gave a significantly different profile from that of the parental CHO cells in a manner reflecting denoted biosynthetic features. Hence, the developed lectin microarray system is considered to be fully applicable for differential glycan profiling of crude samples.

Development of a Lectin Microarray Based on an Evanescent‐Field Fluorescence Principle

To investigate protein-carbohydrate interactions in a comprehensive and high-throughput manner, carbohydrate biosensors including microarrays have recently attracted increased attention. In this context, carbohydrate and lectin microarrays are emerging as techniques to meet such requisites. However, most of these methods adopt a conventional immuno-detection system, which requires repetitive washing steps before detection. Since lectin-carbohydrate interactions are relatively weak compared with those between antigens and antibodies, a more precise analytical method, which does not require any washing step, is desirable. We describe here a novel platform for lectin microarray that enables direct observation of lectin-carbohydrate interactions under equilibrium conditions, on the basis of an evanescent-field fluorescence-assisted detection principle. This method allows the analysis of a panel of glycoproteins (glycopeptides) in an extremely sensitive manner. The system also allows real-time observation of lectin-glycoprotein interactions in an aqueous phase. No washing procedures are required, thus relatively weak interactions are detectable. The described lectin microarray is expected to be useful for various fields of glycomics requiring high-throughput analysis of not only purified glycoproteins but also of crude samples.

Evanescent-field fluorescence-assisted lectin microarray: a new strategy for glycan profiling

Glycans have important roles in living organisms with their structural diversity. Thus, glycomics, especially aspects involving the assignment of functional glycans in a high-throughput manner, has been an emerging field in the postproteomics era. To date, however, there has been no versatile method for glycan profiling. Here we describe a new microarray procedure based on an evanescent-field fluorescence-detection principle, which allows sensitive, real-time observation of multiple lectin-carbohydrate interactions under equilibrium conditions. The method allows quantitative detection of even weak lectin-carbohydrate interactions (dissociation constant, K(d) > 10(-6) M) as fluorescent signals for 39 immobilized lectins. We derived fully specific signal patterns for various Cy3-labeled glycoproteins, glycopeptides and tetramethylrhodamine (TMR)-labeled oligosaccharides. The obtained results were consistent with the previous reports of glycoprotein and lectin specificities. We investigated the latter aspects in detail by frontal affinity chromatography, another profiling method. Thus, the developed lectin microarray should contribute to creation of a new paradigm for glycomics.

Proliferative response of peripheral blood mononuclear cells and levels of antibody to recombinant protein from Propionibacterium acnes DNA expression library in Japanese patients with sarcoidosis

BACKGROUND AND AIM OF THE WORK

The causes of sarcoidosis are unknown. Propionibacterium acnes has been isolated from sarcoid lesions, and many genomes of P. acnes or P. granulosum have been detected in all biopsy samples tested from Japanese patients with sarcoidosis. We searched for protein antigens from propionibacteria that caused immune responses in patients with sarcoidosis but not in subjects without sarcoidosis.

METHODS

A lambda gt11 genomic DNA expression library of P. acnes was screened with sera from patients with sarcoidosis. Antibodies to a recombinant protein from the insert recovered by the screening were measured in serum and bronchoalveolar lavage (BAL) fluid from patients with or without sarcoidosis by an immunofluorescence-based method. Peripheral blood mononuclear cells from patients with and without sarcoidosis were used to examine the lymphoproliferative response to the protein.

RESULTS

Of 180,000 plaques screened, two clones coded for an identical recombinant protein, termed RP35, were recognized by sera. RP35 was the C-terminal region of P. acnes trigger factor. RP35 caused sarcoidosis specific proliferation of the mononuclear cells from 9 (18%) of the 50 patients with sarcoidosis; in a similar way, purified protein derived from Mycobacterium tuberculosis evoked specific responses in 8 (38%) of 21 patients with tuberculosis. Serum levels of IgG and IgA antibodies to RP35 were high in patients with sarcoidosis and other lung diseases. In BAL fluid levels IgG or IgA antibodies were high in 7 (18%) and 15 (39%), respectively, of 38 patients with sarcoidosis, and in 2 (3%) and 2 (3%), respectively, of 63 patients with other lung diseases.

CONCLUSIONS

The RP35 protein from P. acnes causes a cellular immune response in some patients with sarcoidosis but not in subjects without sarcoidosis.

Impaired splenic erythropoiesis in phlebotomized mice injected with CL2MDP-liposome: an experimental model for studying the role of stromal macrophages in erythropoiesis

Erythropoiesis occurs in the presence of erythropoietin (EPO) without macrophages in vitro. In hematopoietic tissues, however, erythroid cells associate closely with stromal macrophages, forming erythroblastic islands via interactions with adhesion molecules. To elucidate the role of macrophages in erythropoiesis, we selectively abrogated stromal macrophages of splenic red pulp of phlebotomized mice by injection with dichloromethylene diphosphonate encapsulated in multilamellar liposomes (CL2MDP-liposome). In the spleen, no erythropoietic activity occurred until 5 days after the treatment. Colony assay revealed that the erythropoiesis was suppressed at the level of CFU-E. The splenic erythropoietic activity gradually developed from day 6 after the treatment, when F4/80+ macrophages began to appear in the red pulp. EPO mRNA was expressed in kidney but not in liver or spleen of phlebotomized mice injected with CL2MDP-liposome, and the serum EPO concentration in these mice was higher than that in phlebotomized mice. These findings suggest that abrogation of stromal macrophages by injection with CL2MDP-liposome impairs the splenic microenvironment for erythropoiesis induced by hypoxic stress, and this may be an excellent experimental model for further characterization of the in vivo role of splenic macrophages in erythropoiesis.

Expression of scavenger receptor class A and CD14 in lipopolysaccharide-induced lung injury

CD14 and macrophage scavenger receptor class A type I and II (MSR-A) are receptors for lipopolysaccharide (LPS). In this study, the expressions of both receptors in the lung after administration of LPS in aerosol to mice with a nebulizer were observed. Bronchiolar epithelial cells and alveolar macrophages immediately incorporated LPS and expressed CD14. CD14-positive neutrophils then appeared in the alveolar space followed by the appearance of MSR-A-expressing cells in the vascular lumen, pulmonary interstitium, and alveolar space. Numbers of apoptotic cells increased after 1 day, and MSR-A-expressing macrophages actively incorporated apoptotic bodies. Daily administration of macrophage colony stimulating factor (M-CSF) to the mice resulted in increased levels of MSR-A expression and reduced levels of CD14 as well as several cytokine expressions, leading to shortening of the inflammatory process. The numbers of apoptotic cells were reduced in M-CSF injected mice. These findings imply that CD14 acts as an immediate expressing receptor for LPS and MSR-A exerts a protective function by scavenging LPS and apoptotic cells in LPS-induced lung injury.

The role of Kupffer cells and regulation of neutrophil migration into the liver by macrophage inflammatory protein-2 in primary listeriosis in mice

Depletion of mouse Kupffer cells and splenic macrophages following intravenous administration of liposome-entrapped clodronate severely reduced host resistance to primary infection with Listeria monocytogenes. Infection of clodronate-treated mice with a sublethal dose of L. monocytogenes resulted in death of the mice within 3 days. The macrophage depletion resulted in marked increases in bacterial growth in the liver and spleen, but not in other tissues. The proliferation of L. monocytogenes was observed in a large number of hepatocytes that underwent apoptosis. Infiltration of neutrophils in the liver and rapid formation of microabscesses were observed in the control mice after L. monocytogenes infection. However, there was less accumulation of neutrophils in the liver of Kupffer cell-depleted mice than in the control mice. Expression of macrophage inflammatory protein-2 (MIP-2) was enhanced in the livers of both the control and Kupffer cell-depleted mice after L. monocytogenes infection. MIP-2 was also induced in a murine hepatocyte cell line following L. monocytogenes infection. The administration of neutralizing anti-interleukin-8 receptor homolog antibody severely abrogated neutrophil infiltration into the Listeria-infected mouse liver. Anti-MIP-2 antibody moderately reduced neutrophil infiltration and microabscess formation in the liver. These findings indicate that Kupffer cells protect hepatocytes from L. monocytogenes infection and the resultant apoptosis. Moreover, MIP-2 and its related molecules produced by the infected hepatocytes regulate neutrophil infiltration and microabscess formation in primary listeriosis.

Complete remission of multiple hepatocellular carcinomas associated with hepatitis C virus-related, decompensated liver cirrhosis by oral administration of enteric-coated tegafur/uracil

We report a case of complete remission of multiple hepatocellular carcinomas after oral administration of enteric-coated tegafur/uracil. A 77-yr-old woman was diagnosed as having recurrent hepatocellular carcinoma associated with decompensated liver cirrhosis. We administered enteric-coated tegafur/uracil to this patient. After 1 month of oral administration, there was a decrease in tumor markers. An image analysis showed disappearance of hepatocellular carcinoma. No recurrence of the hepatocellular carcinoma was recognized for 18 months up to the time of the patient's death, which was due to massive bleeding from a hemorrhagic rectal ulcer. At autopsy, the tumor lesion had necrotized. Oral administration of enteric-coated granules containing tegafur/uracil may provide an effective treatment for hepatocellular carcinoma.

Protective effect of NK1.1(+) T cells as well as NK cells against intraperitoneal tumors in mice

Peritoneal resident cells of mice normally contain small populations of NK cells and NK1.1(+) alphabetaT cells. These populations increased after either 3LL or EL4 tumor inoculations into the peritoneal cavity. In vivo depletion of NK cell alone by anti-asialo GM1 (ASGM1) Ab significantly decreased survival time of tumor-injected mice, while depletion of both NK cells and NK1.1(+) T cells by anti-NK 1.1 Ab greatly shortened mouse survival time. NK1. 1(+) T cells in peritoneal cavity consist of a larger proportion of double-negative T cells and smaller populations of CD4(+) T cells and Vbeta8(+) T cells compared with liver NK1.1(+) T cells and normally lack Vbeta2(+) T cells. Tumor inoculation induced rapid IL-12 and IFN-gamma mRNA in tumor-infiltrating mononuclear cells (TIM). Although anti-NK1 Ab pretreatment in vivo abrogated IFN-gamma mRNA expression and IFN-gamma production of TIM, NK cell depletion alone by anti-ASGM1 Ab pretreatment retained IFN-gamma mRNA expression and partly inhibited IFN-gamma production of TIM. Peritoneal NK cells as well as NK1.1(+) T cells but not NK1.1(-) T cells of 3LL cell- or EL4 cell-injected mice showed cytotoxicities against the same tumor cells. Further, either anti-IL-12 Ab or anti-IFN-gamma Ab ip injection significantly shortened EL4 cell-inoculated mouse survival time. Our findings suggest that peritoneal macrophages activated by tumors produce IL-12 which activates NK cells and NK1.1(+) T cells to produce IFN-gamma and both NK cells and NK1.1(+) T cells are important in suppressing the growth of the intraperitoneal tumors.

Bone remodeling and macrophage differentiation in osteopetrosis (op) mutant mice defective in the production of macrophage colony-stimulating factor

Mice homozygous for the osteopetrosis (op) mutation are characterized by defective differentiation of osteoclasts, monocytes, and tissue macrophages due to a lack of functional macrophage colony-stimulating factor (M-CSF/CSF-1) activity. In young (4-6 week-old) op/op mice, the bone marrow cavities were filled with spongious bone. In aged (50-72 week-old) op/op mice, the bone marrow cavities were markedly reconstructed and marrow hematopoiesis was expanded. Numbers of osteoclasts and bone marrow macrophages in aged op/op mice were increased but most of the osteoclasts were mononuclear cells and showed poorly developed ruffled borders. Lysosomes of bone marrow macrophages were laden with abundant crystalloid materials in aged op/op mice and aged littermate mice. However, such macrophages were not observed in young op/op mice nor in young littermates. In contrast to the marked increase in numbers of osteoclasts and macrophages in the bone marrow, the number of Kupffer cells in the liver did not increase in aged op/op mice. Kupffer cells in aged op/op mice did not show ultrastructural maturation with aging and contained a few crystalloid structures. M-CSF administration to aged op/op mice induced numerical increases in Kupffer cells and lysosomes in Kupffer cells, disappearance of crystalloid structures in lysosomes of Kupffer cells, and the development of ruffled border in osteoclasts. These findings indicate that M-CSF-independent mechanisms for macrophage and osteoclast development in aged op/op mice are restricted to bone marrow. M-CSF plays important roles in the differentiation of macrophage and osteoclast and the production and function of lysosomes.