Granulysin activates antigen-presenting cells through TLR4 and acts as an immune alarmin.
Granulysin (GNLY), an antimicrobial protein present in the granules of human cytotoxic T lymphocytes and natural killer (NK) cells, is produced as an intact 15-kDa form that is cleaved to yield a 9-kDa form. Alarmins are endogenous mediators that can induce recruitment and activation of antigen-presenting cells (APCs) and consequently promote the generation of immune response. We hypothesized that GNLY might function as an alarmin. Here, we report that both 9- and 15-kDa forms of recombinant GNLY-induced in vitro chemotaxis and activation of both human and mouse dendritic cells (DCs), recruited inflammatory leucocytes, including APCs in mice, and promoted antigen-specific immune responses upon coadministration with an antigen. GNLY-induced APC recruitment and activation required the presence of Toll-like receptor 4. The observed activity of recombinant GNLY was not due to endotoxin contamination. The capability of the supernatant of GNLY-expressing HuT78 cells to activate DC was blocked by anti-GNLY antibodies. Finally we present evidence that supernatants of degranulated human NK92 or primary NK cells also activated DCs in a GNLY- and Toll-like receptor 4-dependent manner, indicating the physiologic relevance of our findings. Thus, GNLY is the first identified lymphocyte-derived alarmin capable of promoting APC recruitment, activation, and antigen-specific immune response.
Tewary
Poonam
P
Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute- Frederick/NIH, Frederick, MD, USA.
Yang
De
D
de la Rosa
Gonzalo
G
Li
Yana
Y
Finn
Michael W
MW
Krensky
Alan M
AM
Clayberger
Carol
C
Oppenheim
Joost J
JJ
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000008:administration & dosage / Q000276:immunology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D002478:Cells, Cultured; D002633:Chemotaxis; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D007962:Leukocytes / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D053594:Myeloid Differentiation Factor 88 / Q000276:immunology; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; C075005:GNLY protein, human; D053594:Myeloid Differentiation Factor 88; D011994:Recombinant Proteins; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4