title: Characterization of dendritic cells generated in vivo by an E. coli derived chimeric dual receptor agonist.
abstract: BACKGROUND
  Progenipoietin-4 (ProGP-4) is an E. coli derived chimeric growth factor that activates the human Flt3 and G-CSF receptors. ProGP-4 possesses cross-species activity and treatment of mice with ProGP-4 results in increases in the number of WBC and Class II+/CD11c+ cells in both spleen and peripheral blood. Herein, we report morphologic, phenotypic and functional evaluation of Class II+/CD11c+ cells generated by in vivo administration of ProGP-4.
  
  
  METHODS
  C57BL/6 mice were injected daily with ProGP for 7 to 18 days. Leukocytes from spleen and peripheral blood were analyzed by flow cytometry to enumerate and characterize changes in DC populations. Spleens from ProGP treated mice were evaluated by immunocytochemistry and enriched CD11c+ populations were functionally assessed in a mixed lymphocyte assay and in an antigen dependent CTL assay.
  
  
  RESULTS
  Administration of this dual receptor agonist to mice resulted in dose-dependent increases in the numbers of total white blood cells and Class II+/CD11c+ cells in spleen and peripheral blood. CD11c+ cells from ProGP-4 treated mice co-expressed DEC205 and also expressed CD80, CD86 and CD40, albeit at lower levels as compared to Class II+/CD11c+ cells from untreated animals. Despite lower co-stimulatory molecule expression, ProGP-4-generated Class II+/CD11c+ cells stimulated proliferation of allogeneic T cells and an antigen-specific T cell hybridoma as efficiently as bone marrow derived dendritic cells from untreated mice.
  
  
  CONCLUSIONS
  The data presented in this report highlight the ability of E. coli derived ProGP-4 to expand large numbers of functional DC in the peripheral blood and lymphoid organs in vivo using a rodent model of hematopoiesis. E. coli derived chimeric receptor agonists such as ProGP-4 may enable further investigations of immunotherapeutic approaches to the treatment of diseases such as cancer and autoimmunity.
authors.affiliation: Pharmacia Corporation, St. Louis, Missouri, USA. larry.e.kahn@pharmacia.com
authors.forename: Larry E
authors.initials: LE
authors.lastname: Kahn
authors.forename: Parul D
authors.initials: PD
authors.lastname: Doshi
authors.forename: Kelly L
authors.initials: KL
authors.lastname: McGarity
authors.forename: Mingfu
authors.initials: M
authors.lastname: Yu
authors.forename: Christine P
authors.initials: CP
authors.lastname: Bono
authors.forename: Wen-Rong
authors.initials: WR
authors.lastname: Lie
authors.forename: Anne M
authors.initials: AM
authors.lastname: Rankin
authors.forename: Mary L
authors.initials: ML
authors.lastname: Smidt
authors.forename: Philip R
authors.initials: PR
authors.lastname: Streeter
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Klein
authors.forename: Joseph K
authors.initials: JK
authors.lastname: Welply
authors.forename: Susan L
authors.initials: SL
authors.lastname: Woulfe
mesh_terms: D000818:Animals; D039521:CD11c Antigen / Q000378:metabolism; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D006133:Growth Substances / Q000494:pharmacology*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D007167:Immunotherapy; D008565:Membrane Proteins / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000819:agonists*; D020794:Receptor Protein-Tyrosine Kinases; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000819:agonists*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D011994:Recombinant Proteins; D051941:fms-Like Tyrosine Kinase 3
chemical_list: D039521:CD11c Antigen; D003115:Colony-Stimulating Factors; D006133:Growth Substances; D000949:Histocompatibility Antigens Class II; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C084881:flt3 ligand protein; C434603:progenipoietin-1; C497970:FLT3 protein, human; C497971:Flt3 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3