| First Author | Byrne SM | Year | 2012 |
| Journal | J Immunol | Volume | 189 |
| Issue | 3 | Pages | 1133-43 |
| PubMed ID | 22745374 | Mgi Jnum | J:189782 |
| Mgi Id | MGI:5446988 | Doi | 10.4049/jimmunol.1003406 |
| Citation | Byrne SM, et al. (2012) Cathepsin B controls the persistence of memory CD8+ T lymphocytes. J Immunol 189(3):1133-43 |
| abstractText | The persistence of memory T lymphocytes confers lifelong protection from pathogens. Memory T cells survive and undergo homeostatic proliferation (HSP) in the absence of Ag, although the cell-intrinsic mechanisms by which cytokines drive the HSP of memory T cells are not well understood. In this study we report that lysosome stability limits the long-term maintenance of memory CD8(+) T cell populations. Serine protease inhibitor (Spi) 2A, an anti-apoptotic cytosolic cathepsin inhibitor, is induced by both IL-15 and IL-7. Mice deficient in Spi2A developed fewer memory phenotype CD44(hi)CD8(+) T cells with age, which underwent reduced HSP in the bone marrow. Spi2A was also required for the maintenance of central memory CD8(+) T cell populations after acute infection with lymphocytic choriomeningitis virus. Spi2A-deficient Ag-specific CD8(+) T cell populations declined more than wild-type competitors after viral infection, and they were eroded further after successive infections. Spi2A protected memory cells from lysosomal breakdown by inhibiting cathepsin B. The impaired maintenance of Spi2A-deficient memory CD8(+) T cells was rescued by concomitant cathepsin B deficiency, demonstrating that cathepsin B was a physiological target of Spi2A in memory CD8(+) T cell survival. Our findings support a model in which protection from lysosomal rupture through cytokine-induced expression of Spi2A determines the long-term persistence of memory CD8(+) T cells. |
