ABSTRACT
In acute myelogenous leukemia (AML) and adult T-cell leukemia, it has been demonstrated that the transcription factor LIL-STAT is constitutively activated. To identify and characterize this unknown LIL-STAT protein, electrophoretic mobility shift assay (EMSA) and oligoprecipitation assays were performed by using lipopolysaccharide/interleukin-1 (IL-1)-responsive element (LILRE) oligonucleotide probes. EMSA demonstrated a significant increase in LIL-STAT binding to the LILRE oligonucleotides after interferon gamma (IFN-gamma) and IL-6 stimulation of THP-1 cells. In unstimulated THP-1 and AML cells, LILRE oligonucleotide probes bound only to STAT1 alpha and beta isoforms. The LILRE element showed a significant increase in binding of both alpha and beta isoforms of STAT1 and STAT3 upon IFN-gamma and IL-6 stimulation. Similar results were observed with human monocytes upon IL-6 or IFN-gamma stimulation. These studies indicate that LIL-STAT consists of STAT1 and STAT3 proteins that bind to the LILRE DNA consensus site in a stimulus-dependent way.
Subject(s)
Interferon-gamma/pharmacology , Interleukin-6/pharmacology , Leukemia, Monocytic, Acute/metabolism , Transcription Factors/analysis , Binding Sites , Chemical Precipitation , DNA-Binding Proteins/metabolism , Electrophoretic Mobility Shift Assay , Humans , Interleukin-1/pharmacology , Lipopolysaccharides/pharmacology , Monocytes/chemistry , Monocytes/metabolism , Oligonucleotide Probes/metabolism , Response Elements , STAT1 Transcription Factor , STAT3 Transcription Factor , Trans-Activators/metabolism , Tumor Cells, CulturedABSTRACT
In response to viral infection, unprimed naive CD8(+), major histocompatibility complex class I-restricted, virus-specific T cells clonally expand and differentiate into memory- and effector-type cells. Changes in CD8(+) subset distribution were studied in 17 subjects with acute human immunodeficiency virus type 1 infection and in 14 subjects with acute Epstein-Barr virus (EBV) infection, with combined CD45RO, CD27, and CD28 monoclonal antibodies. A vast expansion of memory-type CD45RO(+)CD27(+)CD8(+) T cells, with high expression of the cell-cycle marker Ki-67, was observed in both infections. Strikingly, CD45RO(+)CD27(+)CD28(-) cells increased >10-fold in acute viral infection and had high Ki-67 expression. In acute EBV infection, a substantial portion of the expanded T cells were EBV-peptide specific. These cells resided mainly in the CD45RO(+)CD27(+) subpopulation, with most in the CD27(+)CD28(-) subpopulation. Content of perforin expression, as a measure of cytotoxic capacity, was relatively low in the CD27(+)CD28(+) T cells and highest in the CD27(-)CD28(-) subpopulation.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Epstein-Barr Virus Infections/immunology , HIV Infections/immunology , HIV-1/immunology , T-Lymphocyte Subsets/immunology , CD28 Antigens , Cytotoxicity Tests, Immunologic , HLA-B8 Antigen , Humans , Ki-67 Antigen/isolation & purification , Leukocyte Common Antigens , Membrane Glycoproteins/isolation & purification , Peptide Fragments , Perforin , Pore Forming Cytotoxic Proteins , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Tumor Necrosis Factor Receptor Superfamily, Member 7ABSTRACT
The amino acid sequences of the pancreatic ribonucleases from African porcupine (Hystrix cristata) and casiragua (Proechimys guairae, a caviomorph rodent species related to the coypu) were determined. The ribonucleases were isolated form minces of pancreatic tissue which had been used for the extraction of the insulins. The results of the sequence determinations of residues 67-78 in both enzymes were ambiguous. Therefore, homology with other ribonucleases has been used in deriving these sequences. At position 94 aspartic acid was found, while all other ribonuclease sequenced to date have asparagine at this position. This may indicate a specific deamidation as a result of the acidic conditions during the extraction of insulin. The amino acid sequence of African porcupine ribonuclease shows a close relationship with those of the South-American caviomorph rodents, which implies that the hystricomorph suborder of the rodents, to which both the African porcupine and the caviomorphs belong, is a natural (evolutionary) taxon. Both porcupine and casiragua ribonuclease are glycoproteins with complex-type carbohydrate chains attached to asparagine-34.
