Differential expression of granzyme B and C in murine cytotoxic lymphocytes.
Cytotoxic lymphocytes use the granule exocytosis pathway to kill pathogen-infected cells and tumor cells. Although many genes in this pathway have been extensively characterized (e.g., perforin, granzymes A and B), the role of granzyme C is less clear. We therefore developed a granzyme C-specific mAb and used flow cytometry to examine the expression of granzyme B and C in the lymphocyte compartments of wild-type and mutant GzmB(-/-) cre mice, which have a small deletion in the granzyme B gene. We detected granzyme B and C expression in CD4(+) and CD8(+) T cells activated with CD3/CD28 beads or MLRs. Stimulation of NK cells in vitro with IL-15 also induced expression of both granzymes. Granzyme C up-regulation was delayed relative to granzyme B in wild-type lymphocytes, whereas GzmB(-/-) cre cells expressed granzyme C earlier and more abundantly on a per-cell basis, suggesting that the deleted 350-bp region in the granzyme B gene is important for the regulation of both granzymes B and C. Quantitative RT-PCR revealed that granzyme C protein levels were regulated by mRNA abundance. In vivo, a population of wild-type CD8alphaalpha(+) intraepithelial lymphocytes constitutively expressed granzyme B and GzmB(-/-) cre intraepithelial lymphocytes likewise expressed granzyme C. Using a model of a persistent murine CMV infection, we detected delayed expression of granzyme C in NK cells from infected hosts. Taken together, these findings suggest that granzyme C is activated with persistent antigenic stimulation, providing nonredundant backup protection for the host when granzyme B fails.
Department of Internal Medicine, Division of Oncology, Siteman Cancer Center, Washington University School of Medicine, St Louis, MO 63110, USA.
Sheng F
SF
Cai
Todd A
TA
Fehniger
Xuefang
X
Cao
Joshua C
JC
Mayer
Joel D
JD
Brune
Anthony R
AR
French
Timothy J
TJ
Ley
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D003587:Cytomegalovirus; D003586:Cytomegalovirus Infections / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D005434:Flow Cytometry; D015870:Gene Expression; D053804:Granzymes / Q000096:biosynthesis* / Q000276:immunology; D019409:Interleukin-15 / Q000276:immunology / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D018345:Mice, Knockout; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D019409:Interleukin-15; D053804:Granzymes