Unexpected T-cell diversity in syngeneic graft-versus-host disease revealed by interaction with peptide-loaded soluble MHC class II molecules.
BACKGROUND
Administration of cyclosporine after syngeneic bone marrow transplantation elicits a systemic autoaggression syndrome termed syngeneic graft-versus-host disease (SGVHD). The effector T cells recognize a peptide from the invariant chain termed CLIP (MHC class II invariant chain peptide) presented on MHC class II molecules. Moreover, the N-terminal flanking region of CLIP interacts with the T-cell receptor (TcR) beta chain.


METHODS
The current study uses a novel approach to isolate and examine the responding T cells ex vivo. A soluble MHC class II molecule using immunoglobulin (Ig)G (MHC class II-Ig) as a scaffold was constructed. The MHC class II-Ig molecule loaded with different peptide variants of CLIP (lacking the N-terminal or C-terminal flanking regions of CLIP) was used to isolate antigen-specific T cells from animals with SGVHD by panning or by flow cytometric sorting.


RESULTS
Two subsets of antigen specific T cells restricted by the N- and C-terminal flanking regions of CLIP can be isolated during acute SGVHD that express the Vbeta8.5 TcR determinant but secrete different cytokines (interferon [IFN]-gamma, interleukin [IL]-10) as detected by real-time quantitative polymerase chain reaction (PCR). Spectratyping of the complementarity-determining region 3 regions reveals that the N-terminal CLIP reactive population has greater diversity in both the CDR3 and J regions than the C-terminal CLIP reactive subset. Interestingly, the N-terminal CLIP reactive cells can be preferentially detected in the target tissues during acute SGVHD. However, only IFN-gamma messenger (m)RNA was detected in the tissues.


CONCLUSIONS
The ability to isolate and examine antigen specific T cells ex vivo has revealed unexpected differences in TcR diversity and cytokine production in SGVHD.
Hess
Allan D
AD
Division of Immunology and Hematopoiesis, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, Baltimore, MD 21231, USA. adhess@jhmi.edu
Thoburn
Christopher J
CJ
Chen
Weiran
W
Bright
And Emilie C
AE
D000818:Animals; D000940:Antigenic Variation; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D022801:Complementarity Determining Regions; D000939:Epitopes; D005260:Female; D006086:Graft vs Host Disease / Q000276:immunology* / Q000473:pathology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007371:Interferon-gamma / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D014185:Transplantation, Isogeneic / Q000009:adverse effects
D000944:Antigens, Differentiation, B-Lymphocyte; D022801:Complementarity Determining Regions; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; C045084:invariant chain; D007371:Interferon-gamma