The restricted expression of granzyme M in human lymphocytes

Citation
Tj. Sayers et al., The restricted expression of granzyme M in human lymphocytes, J IMMUNOL, 166(2), 2001, pp. 765-771
Citations number
42
Categorie Soggetti
Immunology
Journal title
JOURNAL OF IMMUNOLOGY
ISSN journal
00221767 → ACNP
Volume
166
Issue
2
Year of publication
2001
Pages
765 - 771
Database
ISI
SICI code
0022-1767(20010115)166:2<765:TREOGM>2.0.ZU;2-T
Abstract
We have analyzed the expression of human granzyme M (Gzm M) in various huma n leukocyte subsets using the specific mAb 4H10, Using FAGS and Western blo tting analysis we compared the expression of Gzm M with that of other granz ymes (Gzm A and Gzm B) and the lytic protein perforin, Human Gzm M was cons titutively highly expressed in NK cells as was perforin and Gzm A. Surprisi ngly, freshly isolated NK cells had very low (sometimes undetectable) level s of Gzm B. In contrast to Gzm B and perforin, Gzm M was not detected in hi ghly purified CD4(+) and CD8(+) T cells either constitutively or after shor t term activation in vitro. However, low levels of Gzm M were observed in s ome T cell clones on prolonged passage in vitro. Gzm M was not detected in highly purified neutrophils, monocytes, or tumor cells of the myelomonocyti c lineage. Examination of minor T cell subsets from human peripheral blood showed detectable Gzm M in CD3(+), CD56(+) T cells and gamma delta T cells. A histological staining procedure was developed that demonstrated a granul ar staining pattern for Gzm M and a cellular distribution similar to that o bserved by Western blotting. These data indicate that the expression of Gzm M does not always correlate with the lytic activity of cytotoxic cells. Ho wever, expression of Gzm M in NK cells, CD3(+), CD56(+) T cells, and gamma delta T cells suggests that this enzyme may play some role in innate immune responses.