The IL-10 and IFN-gamma pathways are essential to the potent immunosuppressive activity of cultured CD8+ NKT-like cells.
BACKGROUND
CD8+ NKT-like cells are naturally occurring but rare T cells that express both T cell and natural killer cell markers. These cells may play key roles in establishing tolerance to self-antigens; however, their mechanism of action and molecular profiles are poorly characterized due to their low frequencies. We developed an efficient in vitro protocol to produce CD8+ T cells that express natural killer cell markers (CD8+ NKT-like cells) and extensively characterized their functional and molecular phenotypes using a variety of techniques.


RESULTS
Large numbers of CD8+ NKT-like cells were obtained through culture of naïve CD8+ T cells using anti-CD3/anti-CD28-coated beads and high dose IL-2. These cells possess potent activity in suppressing the proliferation of naïve responder T cells. Gene expression profiling suggests that the cultured CD8+ NKT-like cells and the naïve CD8+ T cells differ by more than 2-fold for about 3,000 genes, among which 314 are upregulated by more than 5-fold and 113 are upregulated by more than 10-fold in the CD8+ NKT-like cells. A large proportion of the highly upregulated genes are soluble factors or surface markers that have previously been implicated in immune suppression or are likely to possess immunosuppressive properties. Many of these genes are regulated by two key cytokines, IL-10 and IFN-gamma. The immunosuppressive activities of cells cultured from IL-10-/- and IFN-gamma-/- mice are reduced by about 70% and about 50%, respectively, compared to wild-type mice.


CONCLUSIONS
Immunosuppressive CD8+ NKT-like cells can be efficiently produced and their immunosuppressive activity is related to many surface and soluble molecules regulated by IL-10 and IFN-gamma.
Zhou
Li
L
Center for Biotechnology and Genomic Medicine, Medical College of Georgia, 15th Street, Augusta, GA 30912, USA. lzhou@mcg.edu
Wang
Hongjie
H
Zhong
Xing
X
Jin
Yulan
Y
Mi
Qing-Sheng
QS
Sharma
Ashok
A
McIndoe
Richard A
RA
Garge
Nikhil
N
Podolsky
Robert
R
She
Jin-Xiong
JX
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000145:classification / Q000276:immunology*; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007108:Immune Tolerance; D007371:Interferon-gamma / Q000235:genetics / Q000502:physiology*; D016753:Interleukin-10 / Q000235:genetics / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D013491:Suppressor Factors, Immunologic / Q000096:biosynthesis* / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D008565:Membrane Proteins; D013491:Suppressor Factors, Immunologic; D014157:Transcription Factors; D016753:Interleukin-10; D007371:Interferon-gamma