Ephrin-B1 is critical in T-cell development.
Eph kinases are the largest family of receptor tyrosine kinases, and their ligands, ephrins (EFNs), are also cell surface molecules. In this study, we investigated the role of EFNB1 and the Ephs it interacts with (collectively called EFNB1 receptors) in mouse T-cell development. In the thymus, CD8 single positive (SP) and CD4CD8 double positive (DP) cells expressed high levels of EFNB1 and EFNB1 receptors, whereas CD4 SP cells had moderate expression of both. Soluble EFNB1-Fc in fetal thymus organ culture caused significant subpopulation ratio skew, with increased CD4 SP and CD8 SP and decreased DP percentage, while the cellularity of the thymus remained constant. Moreover, in EFNB1-treated fetal thymus organ culture, CD117(+), CD25(+), DP, CD4 SP, and CD8 SP cells all had significantly enhanced proliferation history, according to bromodeoxyuridine uptake. In vitro culture of isolated thymocytes revealed that EFNB1-Fc on solid-phase protected thymocytes from anti-CD3-induced apoptosis, with concomitant augmentation of several antiapoptotic factors, particularly in CD4 SP and CD8 SP cells; on the other hand, soluble EFNB1-Fc promoted anti-CD3-induced apoptosis, as was the case in vivo. This study reveals that EFNB1 and EFNB1 receptors are critical in thymocyte development.
Laboratory of Immunology, Centre Hospitalier de l'Université de Montréal, Montréal, Quebec H2L 4M1, Canada.
Guang
G
Yu
Jianning
J
Mao
Yulian
Y
Wu
Hongyu
H
Luo
Jiangping
J
Wu
D000818:Animals; D017209:Apoptosis; D001973:Bromodeoxyuridine / Q000494:pharmacology; D017252:CD3 Complex / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D036387:Ephrin-B1 / Q000502:physiology*; D005434:Flow Cytometry; D017403:In Situ Hybridization; D051379:Mice; D008807:Mice, Inbred BALB C; D009693:Nucleic Acid Hybridization; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism; D013997:Time Factors
D017252:CD3 Complex; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D036387:Ephrin-B1; D015375:Receptors, Interleukin-2; D019009:Proto-Oncogene Proteins c-kit; D001973:Bromodeoxyuridine