S Devereux

Development of antibodies to unprotected glycosylation sites on recombinant human GM-CSF

In 4 out of 16 patients receiving recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) in phase I/II studies antibodies developed to the recombinant protein. The antibodies react with sites on the native protein backbone which are normally protected by O-linked glycosylation but which are exposed in rhGM-CSF produced in yeast and Escherichia coli. Antigenicity of recombinant human proteins due to non glycosylation may have relevance to the choice of host system for production of factors for clinical use.

A Clinically Applicable Method for the ex vivo Generation of Antigen‐Presenting Cells from CD34+ Progenitors

Background and Objectives: Dendritic cells (DCs), the most potent of antigen–presenting cells, can be generated in vitro from bone marrow or blood progenitor cells. We have developed a method for producing such cells from mobilised peripheral blood CD34+ cells in the absence of bovine products. Methods: The culture system developed used X–Vivo 10 culture medium with 10% autologous serum, rhGM–CSF, rhTNF–α and rhIL–4. Large–scale cultures were performed in Stericell 12 inch × 15 inch culture bags. Results: In 12–small–scale experiments, over 14 days, there was a median 38–fold increase in cell numbers of which 12.8% were DCs as defined by immunophenotyping. These cells had potent DC activity in functional assays. In two clinical–scale experiments, a 5.7– and 10–fold expansion of total cell numbers was obtained, with 8.2 and 18% of the final population being DCs, respectively. Conclusion: This system is suitable for clinical application.