title: Signal regulatory protein molecules are differentially expressed by CD8- dendritic cells.
abstract: A normalized subtracted gene expression library was generated from freshly isolated mouse dendritic cells (DC) of all subtypes, then used to construct cDNA microarrays. The gene expression profiles of the three splenic conventional DC (cDC) subsets were compared by microarray hybridization and two genes encoding signal regulatory protein beta (Sirpbeta1 and Sirpbeta4) molecules were identified as differentially expressed in CD8(-) cDC. Genomic sequence analysis revealed a third Sirpbeta member localized in the same gene cluster. These Sirpbeta genes encode cell surface molecules containing extracellular Ig domains and short intracytoplasmic domains that have a charged amino acid in the transmembrane region which can potentially interact with ITAM-bearing molecules to mediate signaling. Indeed, we demonstrated interactions between Sirpbeta1 and beta2 with the ITAM-bearing signaling molecule Dap12. Real-time PCR analysis showed that all three Sirpbeta genes were expressed by CD8(-) cDC, but not by CD8(+) cDC or plasmacytoid pre-DC. The related Sirpalpha gene showed a similar expression profile on cDC subtypes but was also expressed by plasmacytoid pre-DC. The differential expression of Sirpalpha and Sirpbeta1 molecules on DC was confirmed by staining with mAbs, including a new mAb recognizing Sirpbeta1. Cross-linking of Sirpbeta1 on DC resulted in a reduction in phagocytosis of Leishmania major parasites, but did not affect phagocytosis of latex beads, perhaps indicating that the regulation of phagocytosis by Sirpbeta1 is a ligand-dependent interaction. Thus, we postulate that the differential expression of these molecules may confer the ability to regulate the phagocytosis of particular ligands to CD8(-) cDC.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia. lahoud@wehi.edu.au
authors.forename: Mireille H
authors.initials: MH
authors.lastname: Lahoud
authors.forename: Anna I
authors.initials: AI
authors.lastname: Proietto
authors.forename: Kate H
authors.initials: KH
authors.lastname: Gartlan
authors.forename: Susie
authors.initials: S
authors.lastname: Kitsoulis
authors.forename: Joan
authors.initials: J
authors.lastname: Curtis
authors.forename: James
authors.initials: J
authors.lastname: Wettenhall
authors.forename: Mariam
authors.initials: M
authors.lastname: Sofi
authors.forename: Carmel
authors.initials: C
authors.lastname: Daunt
authors.forename: Meredith
authors.initials: M
authors.lastname: O'keeffe
authors.forename: Irina
authors.initials: I
authors.lastname: Caminschi
authors.forename: Keith
authors.initials: K
authors.lastname: Satterley
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rizzitelli
authors.forename: Petra
authors.initials: P
authors.lastname: Schnorrer
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hinohara
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Li
authors.initials: L
authors.lastname: Wu
authors.forename: Gordon
authors.initials: G
authors.lastname: Smyth
authors.forename: Emanuela
authors.initials: E
authors.lastname: Handman
authors.forename: Ken
authors.initials: K
authors.lastname: Shortman
authors.forename: Mark D
authors.initials: MD
authors.lastname: Wright
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016827:CD8 Antigens / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D015723:Gene Library; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics*; D015398:Signal Transduction / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D016827:CD8 Antigens; D011956:Receptors, Cell Surface; C501921:SIRPB1 protein, human