A splice variant of human ephrin-A4 encodes a soluble molecule that is secreted by activated human B lymphocytes.
Ephrin-A4 is a ligand for the erythropoietin-producing hepatocellular (Eph) receptor family of tyrosine kinases. We have identified a secreted form of ephrin-A4, denoted ephrin-A4 (s), which is encoded by an alternatively spliced mRNA and is produced by in vivo activated B cells in tonsils. Blood B cells secrete ephrin-A4 (s) upon stimulation via the B-cell antigen receptor. A subpopulation of tonsil cells in the crypts with a dendritic cell phenotype was shown to express EphA2, an Eph receptor tyrosine kinase that was found to be capable of binding an ephrin-A4 immunoglobulin chimeric protein. We conclude that ephrin-A4 (s) may play a role in the interaction between activated B lymphocytes and dendritic cells in human tonsils. (Blood. 2000;95:221-230)
Aasheim
H C
HC
Department of Immunology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway. h.c.asheim@labmed.uio.no
Munthe
E
E
Funderud
S
S
Smeland
E B
EB
Beiske
K
K
Logtenberg
T
T
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D003001:Cloning, Molecular; D036385:Ephrin-A4; D005091:Exons; D014644:Genetic Variation; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D007438:Introns; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D014066:Palatine Tonsil / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D036385:Ephrin-A4; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins