Granzyme A-deficient mice retain potent cell-mediated cytotoxicity.
Granzyme A, a granule-associated serine proteinase of activated cytotoxic T cells and natural killer cells, has been reported to play a critical role in DNA fragmentation of target cells. To address the question of the biological role of granzyme A, we have now generated a granzyme A-deficient mouse mutant by homologous recombination. Western blot analysis, enzyme assays and reverse transcription-PCR confirmed the absence of granzyme A in activated T cells. In addition, deletion of granzyme A does not alter the expression patterns of other granule components, such as granzymes B-G and perforin. Granzyme A-deficient mice are healthy and show normal hematopoietic development. Most notably, their in vitro- and ex vivo-derived cytotoxic T cells and natural killer cells are indistinguishable from those of normal mice in causing membrane disruption, apoptosis and DNA fragmentation in target cells. Furthermore, granzyme A-deficient mice readily recover from both lymphocytic choriomeningitis virus and Listeria monocytogenes infections and eradicate syngeneic tumors with kinetics similar to the wild-type strain. These results demonstrate that granzyme A does not play a primary role in cell-mediated cytotoxicity, as has been assumed previously.
Ebnet
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Max-Planck-Institut für Immunbiologie, Freiburg, Germany.
Hausmann
M
M
Lehmann-Grube
F
F
Müllbacher
A
A
Kopf
M
M
Lamers
M
M
Simon
M M
MM
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D003602:Cytotoxicity, Immunologic; D017931:DNA Primers; D005091:Exons; D005434:Flow Cytometry; D015870:Gene Expression; D053804:Granzymes; D006410:Hematopoiesis / Q000235:genetics; D007694:Killer Cells, Natural / Q000201:enzymology* / Q000276:immunology; D008089:Listeria monocytogenes; D008088:Listeriosis / Q000276:immunology; D008213:Lymphocyte Activation; D008216:Lymphocytic Choriomeningitis / Q000276:immunology; D008217:Lymphocytic choriomeningitis virus; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012697:Serine Endopeptidases / Q000172:deficiency* / Q000235:genetics*; D013602:T-Lymphocytes, Cytotoxic / Q000201:enzymology* / Q000276:immunology; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D012333:RNA, Messenger; D053804:Granzymes; D012697:Serine Endopeptidases