title: The regulated long-term delivery of therapeutic proteins by using antigen-specific B lymphocytes.
abstract: Memory lymphocytes are important mediators of the immune response. These cells are long-lived and undergo clonal expansion upon reexposure to specific antigen, differentiating into effector cells that secrete Ig or cytokines while maintaining a residual pool of memory T and B lymphocytes. Here, the ability of antigen-specific lymphocytes to undergo repeated cycles of antigen-driven clonal expansion and contraction is exploited in a therapeutic protocol aimed at regulating protein delivery. The principle of this strategy is to introduce genes encoding proteins of therapeutic interest into a small number of antigen-specific B lymphocytes. Output of therapeutic protein can then be regulated in vivo by manipulating the size of the responder population by antigen challenge. To evaluate whether such an approach is feasible, we developed a mouse model system in which Emu- and Iglambda-based vectors were used to express human erythropoietin (hEPO) gene in B lymphocytes. These mice were then immunized with the model antigen phycoerythrin (PE), and immune splenocytes (or purified PE-specific B lymphocytes) were adoptively transferred to normal or mutant (EPO-deficient) hosts. High levels of hEPO were detected in the serum of adoptively transferred normal mice after PE administration, and this responsiveness was maintained for several months. Similarly, in EPO-deficient anemic recipients, antigen-driven hEPO expression was shown to restore hematocrit levels to normal. These results show that antigen-mediated regulation of memory lymphocytes can be used as a strategy for delivering therapeutic proteins in vivo.
authors.affiliation: Lymphocyte Development Group, Gene Regulation and Chromatin Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College of Science, Technology, Du Cane Road, London W12 ONN, United Kingdom.
authors.forename: Katalin
authors.initials: K
authors.lastname: Takács
authors.forename: Camille
authors.initials: C
authors.lastname: Du Roure
authors.forename: Stephen
authors.initials: S
authors.lastname: Nabarro
authors.forename: Niall
authors.initials: N
authors.lastname: Dillon
authors.forename: John H
authors.initials: JH
authors.lastname: McVey
authors.forename: Zoe
authors.initials: Z
authors.lastname: Webster
authors.forename: Angus
authors.initials: A
authors.lastname: Macneil
authors.forename: István
authors.initials: I
authors.lastname: Bartók
authors.forename: Christopher
authors.initials: C
authors.lastname: Higgins
authors.forename: David
authors.initials: D
authors.lastname: Gray
authors.forename: Matthias
authors.initials: M
authors.lastname: Merkenschlager
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Fisher
mesh_terms: D019264:Adoptive Transfer; D000740:Anemia / Q000276:immunology / Q000628:therapy; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D016503:Drug Delivery Systems; D004921:Erythropoietin / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use; D005260:Female; D015870:Gene Expression; D015316:Genetic Therapy; D006801:Humans; D007114:Immunization; D007156:Immunologic Memory; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010799:Phycoerythrin / Q000276:immunology; D011994:Recombinant Proteins / Q000008:administration & dosage* / Q000235:genetics / Q000627:therapeutic use*
chemical_list: D011994:Recombinant Proteins; D010799:Phycoerythrin; D004921:Erythropoietin