Analysis of immunodominance among minor histocompatibility antigens in allogeneic hematopoietic stem cell transplantation.
In major histocompatibility complex (MHC)-matched allogeneic hematopoietic stem cell transplantation (HSCT), donor responses are directed against multiple host minor histocompatibility antigens (mHAgs), producing graft-versus-host disease (GVHD) and graft-versus-tumor (GVT) effects. We studied MHC-matched, mHAg-mismatched C3H.SW>C57BL/6 HSCT in which three mHAg are molecularly defined (B6dom1, H3, H13) to determine if there is a hierarchy of immunodominance among the mHAgs and to learn the contribution of each to GVHD. We found that B6dom1 was the immunodominant mHAg. B6dom1 did not block responses to the subdominant mHAgs H3 and H13. The mechanism of immunodominance was not mHAg avidity or affinity for class I. B6dom1 elicited a broader variety of Vbeta clonotypes than either H3 or H13. Severe GVHD could occur in the absence of a strong B6dom1 response. Alloreactivity to isolated B6dom1, H3 or H13 differences did not produce severe GVHD. We concluded that immunodominance is explained by both mHAg density on host cells and the repertoire of donor T cells capable of responding to the mHAgs. Clinically significant GVHD requires donor responses to multiple mHAgs. Modulation of responses to a single immunodominant mHAg is insufficient for the prevention of GVHD, while immunotherapies directed against isolated mHAgs may not provoke severe GVHD.
Mori
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Department of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
El-Baki
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H
Mullen
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CA
D000818:Animals; D016026:Bone Marrow Transplantation / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016695:Glycosyltransferases / Q000627:therapeutic use; D006086:Graft vs Host Disease / Q000276:immunology*; D016056:Immunodominant Epitopes / Q000097:blood; D007165:Immunosuppression Therapy / Q000379:methods; D019194:Ischemic Preconditioning / Q000379:methods; D008285:Major Histocompatibility Complex; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens / Q000097:blood*; D010446:Peptide Fragments / Q000627:therapeutic use; D033581:Stem Cell Transplantation / Q000379:methods*; D013601:T-Lymphocytes / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology*; D014916:Whole-Body Irradiation
D016056:Immunodominant Epitopes; D015778:Minor Histocompatibility Antigens; D010446:Peptide Fragments; C469940:SIMP protein (770-778); D016695:Glycosyltransferases