Microanatomical localization of PD-1 in human tonsils

PD-1 is an immunoinhibitory receptor, which belongs structurally to the CD28 family. PD-1-deficient mice show breakdown of peripheral tolerance and manifest multiple autoimmune symptoms. We previously described expression of PD-1 on activated T and B lymphocytes and myeloid cells. However, little is known about the microanatomical distribution of PD-1 in lymphoid organs. In this study, we performed immunohistochemistry using monoclonal antibodies against human PD-1. In human tonsils, PD-1 was expressed on most of T cells and a small subset of centrocytes in the light zone of germinal centers (GCs), where clonal selection of centrocytes takes place. These results suggest that PD-1 may play an important role in GC reaction.     

Production and characterization of monoclonal antibodies to a pilus colonization factor (colonization factor antigen III) of human enterotoxigenic Escherichia coli

Three monoclonal antibodies (MAbs) to a pilus colonization factor (colonization factor antigen III [CFA/III]) of human enterotoxigenic Escherichia coli (ETEC) were developed and characterized. All of the MAbs isolated belonged to the immunoglobulin G2a subclass. The specificity of these MAbs for CFA/III pili was demonstrated by the immunogold-labeling technique. The presence of more than one epitope in CFA/III pili was suggested. One of the three MAbs appears to recognize a polymeric conformational epitope(s) of CFA/III. CFA/III antigenicity distinct from that of other pilus colonization factors of ETEC was demonstrated by both a bacterial agglutination test and a sandwich enzyme-linked immunosorbent assay using the MAbs. Of the 100 strains of ETEC isolated from persons with traveler's diarrhea, 8% were found to carry CFA/III pili. Two enzyme-linked immunosorbent assay systems which could detect as little as several or 50 ng of CFA/III per ml were developed.     

Hepatoblastoma in an 82-year-old man. An autopsy case report

An autopsy case of adult hepatoblastoma is presented. The patient was an 82-year-old male with chronic hepatitis of 7 years' duration. The liver tumor was detected 6 months before death. Autopsy revealed a large hepatic tumor occupying about 80% of the entire liver. Histologically, the tumor showed typical features of mixed epithelial- and mesenchymal-type hepatoblastoma. The epithelial component consisted of fetal and embryonal cell types. The mesenchymal component showed primitive spindle-shaped cells with various degrees of cellularity. Chondroid areas and a few foci of osteoid formation were also present.     

Cloning of TPA-inducible early (TIE) genes by differential hybridization using TPA-Nonresponsive variant of mouse 3T3-L1 cells

The tumor promoter 12-O -tetradecanoylphorbol-13-acetate (TPA) induces DNA synthesis in quiescent 3T3-L1 cells but not in its variant VT-1 cells. A gt10 cDNA library was constructed using poly(A)⁺ RNA from 3T3-L1 cells that were stimulated by TPA for 20 min. Radioactive cDNA probes were prepared from mRNAs of TPA-treated 3 T3-L1 and VT-1 cells and used for screening of the 3T3-L1 cDNA library by differential hybridization. Nine of 6000 phage plaques hybridized only to the 3T3-L1 cDNA probe. Analysis of the nucleotide sequence of five of these clones indicated a high degree of homology with human or mouse type I and type III collagen genes. Three other independent clones showed no homology with any known DNA sequences. These isolated clones of TPA-inducible early (TIE) genes may be useful to study the signal transduction pathway of phorbol esters.     

Malignant meningioma with cartilage and giant cells.

An autopsy case of recurrent and malignant meningioma is reported. This case was originally typical benign transitional meningioma of the falx, however, the histology of the tumor changed to show malignant features during successive recurrences. At autopsy, the tumor revealed findings consistent with malignant meningioma. One of the most interesting features was the presence of cartilage and giant cells in some parts. Immunohistochemistry showed positive immunoreactivity for S-100 protein in some cartilage and giant cells and for cytokeratin in some giant cells. Multidifferential potential of the meningioma cells was suggested in this case.     

Molecular cloning and expression analysis of a macrophage-colony stimulating factor receptor-like gene from rainbow trout, Oncorhynchus mykiss

The M-CSF and its receptor (M-CSFR, CSF-1R or c-fms proto-oncogene) system were initially implicated as essential in mammals for normal monocyte development as well as for pregnancy. To allow a comparison with the M-CSF and M-CSFR system of an oviparous animal, we cloned a M-CSFR-like gene from rainbow trout (Oncorhynchus mykiss). The gene was cloned from a cDNA library of head kidney. It contained an open reading frame encoding 967 amino acids with a predicted size of 109 kDa. The putative amino acid sequence of rainbow trout M-CSFR showed 54% amino acid identity to fugu (Takifugu rubripes) M-CSFR, 52% to zebrafish (Danio rerio) M-CSFR and 40% to mouse (Mus musculus) and human (Homo sapiens) M-CSFR. The M-CSFR-like gene was constitutively expressed in head kidney, kidney, intestine, spleen and blood. The gene was detected especially in the ovary of immature female rainbow trout. These results suggest that a M-CSFR-like receptor may be involved in female reproductive tracts even in an oviparous animal like fish.     

Molecular and immunological approach to hematological disease: detection and analysis of intracellular modified nucleosides by flow cytometry

Modified nucleosides are components of ribosomal RNA (rRNA), transfer RNA (tRNA) and messenger RNA (mRNA). 1-methyladenosine and pseudouridine are members of those modified nucleosides. The urinary concentration of 1-methyladenosine and pseudouridine of cancer patients are higher than that of healthy controls, and those compounds were reduced after effective chemotherapy. Thus those compounds might be expected to use as tumor markers. In this study cellular origin of 1-methyladenosine and pseudouridine were analysed about two tumor cell lines (HUT-102, THP-1), peripheral blood lymphocytes (PBL) from healthy adult and PBL under the phytohemagglutinin stimulation, by flow cytometric analysis and immunofluorescent staining of cellular RNA using monoclonal antibodies specific for 1-methyladenosine (AMA) and pseudouridine (APU). Both 1-methyladenosine and pseudouridine were detected in more than 90% of tumor cells above the thresholds of flow cytometric detection (Spectrum III, Ortho). The PBL under the PHA stimulation also tended to take the same way of the tumor cell lines, whereas few of the PBL contained 1-methyladenosine above the thresholds. According to the DNA analysis of those cell lines, high contents of the modified nucleosides in the cell might follow DNA synthesis, this leads to one reason for high levels of the urinary excretion of the modified nucleosides in cancer patient.     

Detection of the putative E2 protein of hepatitis C virus in human liver

The question was asked whether a predicted envelope protein, considered to be processed from the polyprotein precursor encoded by the putative E2/NS1 region of the hepatitis C virus (HCV) genome, may be observed in HCV-infected humans. Two polyclonal antibodies against recombinant E2/NS1 proteins were prepared and their reactivity tested against liver extracts from HCV-infected patients by immunoblotting analysis. A band corresponding to a size of 44 kDa was detected in liver extracts from patients who were positive for the HCV-specific antibody anti-C100-3 but not in liver extracts from patients who did not have anti-C100-3 antibody. Additionally, no band was detected using preimmune sera or antisera which had been preabsorbed with recombinant E2/NS1 proteins. Deglycosylation studies demonstrated that the 44 kDa protein was a glycosylated form of a 38 kDa protein which corresponds to the predicted molecular weight of the putative E2/NS1 protein. These results suggest that the 44 kDa protein is a product of the E2/NS1 region. Frequent observation of the 44 kDa band in cases of chronic active hepatitis C suggests a correlation between the expression of this protein and the progression of hepatitis. © 1994 Wiley-Liss, Inc.     

Genetics of cell-surface receptors for bioactive polypeptides: A variant of mouse BALBc/3T3 fibroblasts possessing altered insulin-binding ability

An insulin-nonresponsive variant was isolated from mutagenized mouse BALBc/3T3 fibroblasts. Selection was based on the insulin's mitogenic action upon quiescent cells and subsequent arrest at mitosis by vinblastine sulfate to remove insulin-responsive cells. Among four surviving colonies, one, designated IN-2, exhibited no binding for [¹²⁵I] insulin at 2× 10^–10 M and at 4° C. The binding ability, however, recovered substantially at 15° C and increased with higher temperature and at higher ligand concentrations. The binding profiles, Scatchard plot analysis, and the dissociation kinetics indicated that the receptors expressed on IN-2 cells possess lower affinity than the parental 3T3 cells. The IN-2 cells were negative for stimulating effects of insulin on 2-deoxyglucose uptake, thymidine incorporation, and cell growth. The IN-2 cells were also negative for cross-reactivity to antibodies which react with insulin receptors on 3T3 cells and for the susceptibility to a cytotoxic chimeric insulin which was cross-linked to diphtheria toxin fragment A. This negative response of IN-2 cells can be attributed to a deficiency in high-affinity receptors for insulin. The insulin bound to the low-affinity binding sites of IN-2 cells, however, undergoes internalization and intracellular degradation. Therefore, such processing by itself does not account for insulin's mitogenic action.