ABSTRACT
Two genes that are specifically expressed in T cells with cytolytic activity were isolated from a CTL cDNA library by differential screening. Both appear to encode serine proteases, thus suggesting a cascade mechanism, similar to complement, in activated CTL. Both CTL-specific proteases have a number of unusual structural features that suggest that they will have novel substrate specificities. One of the proteins (CCPI) has been oriented to the granules found in the cytoplasm of CTL. Taken together, these data strongly suggest that these molecules play an important role in target-cell lysis by CTL. Furthermore, we believe that the detailed molecular knowledge being accumulated through these studies may lead to the development of innovative forms of immunotherapy.
Subject(s)
Molecular Biology , T-Lymphocytes, Cytotoxic/immunology , Amino Acid Sequence , Animals , Cytoplasmic Granules/enzymology , Cytotoxicity, Immunologic , Immunotherapy , Molecular Sequence Data , Serine Endopeptidases/genetics , Serine Endopeptidases/immunology , T-Lymphocytes, Cytotoxic/ultrastructureABSTRACT
Genes that are expressed exclusively in cytotoxic T cells should encode proteins that are essential for target cell lysis in cell-mediated immune responses. The sequences of two cytotoxic T lymphocyte-specific complementary DNA's (cDNA's) suggest that the two genes encode serine proteases. A full-length cDNA corresponding to one of the genes was isolated and sequenced. The predicted protein resembles serine proteases in that it includes all the residues that form the catalytic triad of the active site of serine proteases. Moreover, it has sequence characteristics thought to occur only in rat mast cell protease type II. These results are in accord with the view that a protease cascade plays a key role in cytotoxic T-cell activation.
Subject(s)
Endopeptidases/genetics , T-Lymphocytes, Cytotoxic/metabolism , Animals , Base Sequence , Cloning, Molecular , DNA/genetics , Genes , Mice , Serine EndopeptidasesABSTRACT
Poly A+ RNA has been purified from phorbol myristate acetate stimulated mouse EL4 cells. Translation, by microinjection into frog oocytes, gave biologically active interleukin 2 (IL2) and colony stimulating factor for granulocytes and macrophages (GM-CSF). These two mRNAs were separated by centrifugation through linear sucrose gradients. The sedimentation coefficients for IL2 and GM-CSF mRNAs were found to be 11.5S and 8S respectively. The clonal and cellular morphologies induced by the oocyte material corresponded to low concentrations of authentic GM-CSF.
Subject(s)
Colony-Stimulating Factors/genetics , Lymphocytes/metabolism , Phorbols/pharmacology , Protein Biosynthesis/drug effects , RNA, Messenger/genetics , Tetradecanoylphorbol Acetate/pharmacology , Animals , Cell Line , Lymphocyte Activation , Lymphocytes/drug effects , Lymphocytes/immunology , Lymphoma/metabolism , Mice , Neoplasms, Experimental/metabolism , Poly A/genetics , RNA/geneticsSubject(s)
Antibody Formation/drug effects , Cortisone/pharmacology , Immunosuppression Therapy , Animals , Antibody-Producing Cells , Antilymphocyte Serum , Ascitic Fluid/immunology , Cell Adhesion , Cells, Cultured , Erythrocytes/immunology , Flagellin , Hemolytic Plaque Technique , Lymphocyte Depletion , Lymphocytes/immunology , Macrophages/immunology , Male , Mercaptoethanol/pharmacology , Mice , Mice, Inbred AKR , Mice, Inbred CBA , Pertussis Vaccine , Salmonella/immunology , Sheep/immunology , Spleen/cytology , T-Lymphocytes/immunologySubject(s)
DNA Replication , DNA/analysis , Deoxyribonucleotides/analysis , Oligonucleotides/analysis , Adenine Nucleotides/analysis , Base Sequence , Carbon Radioisotopes , Cytosine Nucleotides/analysis , DNA/isolation & purification , DNA Nucleotidyltransferases/metabolism , DNA-Directed RNA Polymerases/metabolism , Escherichia coli/enzymology , Ethidium , Guanine Nucleotides/analysis , Kinetics , Micrococcal Nuclease/metabolism , Models, Chemical , Molecular Weight , Phosphoric Diester Hydrolases/metabolism , Phosphorus Radioisotopes , Spleen/enzymology , Thymine Nucleotides/analysis , TritiumSubject(s)
Bacterial Proteins/isolation & purification , DNA Nucleotidyltransferases/antagonists & inhibitors , DNA Replication/drug effects , DNA/analysis , Escherichia coli/analysis , Ammonium Sulfate , Bacterial Proteins/pharmacology , Base Sequence , Chlorides , Chromatography, DEAE-Cellulose , Chromatography, Gel , DNA, Bacterial , Deoxyribonucleases , Deoxyribonucleotides , Drug Stability , Electrophoresis, Polyacrylamide Gel , Escherichia coli/enzymology , Hot Temperature , Lithium , Models, Chemical , Molecular Weight , Protein Denaturation , Sodium Dodecyl Sulfate , UreaSubject(s)
Antibody Formation , Antigens , B-Lymphocytes/immunology , Lectins/pharmacology , T-Lymphocytes/immunology , Animals , Antibody-Producing Cells , Antigen-Antibody Reactions , Autoradiography , Bone Marrow Cells , Bone Marrow Transplantation , Cell Survival , Concanavalin A/pharmacology , Erythrocytes/immunology , Flagella , Fluoresceins/metabolism , Hemolytic Plaque Technique , Mice , Mice, Inbred CBA , Radiation Chimera , Salmonella/immunology , Sheep/immunology , Spleen/cytology , Thymectomy , TritiumABSTRACT
The rate of antigen binding by mouse lymphoid cells has been investigated with polymerized flagellin of Salmonella adelaide that had been biosynthetically labeled with tritium. Autoradiographs of lymphnode cells incubated with the tritiated antigen at 37 degrees showed aggregation of antigen receptors to one cell pole. This was followed 4-5 hr later by the appearance of antigen receptors on the cell surface, at a density severalfold higher than at the time of first contact with the antigen. Antigen-binding cells exposed in vitro to antigen concentrations known to cause high zone tolerance induction failed to form polar antigen caps once they had entered the phase of increased receptor formation. The data suggest that sufficient crosslinking of receptors by the antigen to cause their aggregation triggers the cell to differentiate and to increase its density of antigen receptors. In the presence of antigen concentrations favoring high zone tolerance, receptors may become interlinked to such an extent that they are prevented from aggregation. Such a "frozen" state of the antigen recognition system would render the cell unresponsive to antigenic stimuli.
