Organ-Specific T Cell Receptor Repertoire in Target Organs of Murine Graft-Versus-Host after Haploidentical Bone Marrow Transplantation.

Objective Haploidentical bone marrow transplantation (Haploidentical-BMT) usually has high morbidity and mortality associated with the early complication of SCT and severe GVHD. GVHD-associated T-cell clones can be identified in GVHD-affected tissues. In our study, Murine CB6F1(H-2^b/d, [male]) and C57BL/6(H-2^b, [female]) haploidentical-BMT GVHD model was established and proved a novel method to study the characteristics of T cell receptor repertoire in target organs of murine GVHD and research the molecular characteristics of T cell receptor BV complementarity determining region3 (TCRBV CDR3) repertoires of these monoclonal T cells in liver, skin and ileum.

Methods Murine haploidentical BMT model was established, RT-PCR was used to amplify 24 subfamily genes of TCRBV from liver, skin, ileum, spleen and kidney, PCR products were further analyzed by genescan to evaluate the clonality of BV subfamily and characteristics of CDR3, monoclonal bands were obtained thorough denaturation polyacrylamide gel electrophoresis and sequenced. A group of CDR3 molecules were obtained from GVHD-target tissues.

Results GVHD occurred as early as days 14 and was proven by histology in liver, skin and ileum. After BMT, it emerged a number of new monoclonal and oligoclonal T cells in GVHD-target tissues, while kidney was not affected by GVHD and infiltrated by polycolnal T cell. 48 TCRBV CDR3 molecules of monoclonal T cells which obtained from liver, skin, ileum in different times after BMT have six C’-terminal motifs(TEVFF, DTQYF, YEQYF, A EQ (Y F/FF), QNTLY F, AE T L Y F)and use restricted JB genes(JB1.1, JB2.5, JB2.7, JB2.1, JB2.4, JB2.3).

Conclusion Through murine haploidentical BMT GVHD model, TCRBV CDR3 was detected in GVHD-target tissues (liver, skin, ileum) and found that it emerged a number of monoclonal or oligoclonal T cells which associated with the development of GVHD and existed conserved CDR3 motifs.