Cell adhesion of human haematopoietic progenitors : development of assay techniques

• Main Author: Turner, Marc Leighton
• Published: University of Edinburgh 1996
• Subjects: 612.1
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.663115

Elucidation of the mechanisms underlying the reciprocal phenomena of HPC homing and mobilisation is the objective of this thesis, and may allow the development of novel approaches to mobilisation regimens and/or <I>ex vivo</I> HPC manipulation. Accurate and reproducible assays for quantitative and qualitative studies of HPC were established. These included an immunocytometry based assay of CE34 antigen expression, dual colour immunocytometry studies of cell adhesion molecule, lineage and activation marker expression by HPC derived from different sources, and three colour immunocytometry of adhesion molecule expression within HPC subsets. A chromium<SUP>51</SUP>-labelling technique was developed as a functional assay with which to examine the adhesion of haematopoietic cell lines to extracellular matrix components, stromal and endothelial tissues in culture. A variety of techniques for adhesion blockade were explored. A protocol for high-purity enrichment of HPC was developed, and the feasibility of applying the chromium<SUP>51</SUP> adhesion assay to these cells was examined. CD34 immunocytometry was confirmed as a valid method for defining HPC populations. Marrow HPC were found to express nine adhesion molecules, two of which were reduced by circulating cells. HPC derived from different sources showed variation in lineage and activation marker expression, and HPC subsets displayed differences in adhesion molecule expression. Haematopoietic cell lines adhered to fibronectin and thrombospondin, but not to other extracellular matrix components. Blockade of fibronectin adhesion was effected by divalent cation chelation, synthetic peptides and chondroitinase ABC. Cell line adhesion to stromal and endothelial tissue cultures was demonstrated, but highly-enriched HPC labelled poorly with chromium<SUP>51</SUP>.