title: Expression of macrophage inflammatory protein-1 receptors in human CD34(+) hematopoietic cells and their modulation by tumor necrosis factor-alpha and interferon-gamma.
abstract: Macrophage inflammatory protein-1alpha (MIP-1alpha) can stimulate growth inhibitory and potent chemotactic functions in hematopoietic cells. To investigate whether the action of MIP-1alpha may be regulated at the cellular receptor level, we studied the expression and modulation of MIP-1alpha receptors on CD34(+) cells isolated from normal bone marrow (NBM), umbilical cord blood (CB), and leukapheresis products (LP). Expression of MIP-1alpha receptors on CD34(+) cells was analyzed by two-color flow cytometry using a biotinylated MIP-1alpha molecule. The mean percentage of LP CD34(+) cells expressing the MIP-1alpha receptors was 67.7 +/- 7.2% (mean +/- SEM; n = 22) as compared with 89.9 +/- 2.6% (n = 10) and 74.69 +/- 7.04% (n = 10) in CB and NBM, respectively (P = .4). The expression of the MIP-1alpha receptor subtypes on LP CD34(+) cells was studied by indirect immunofluorescence using specific antibodies for the detection of CCR-1, CCR-4, and CCR-5. Microscopical examination revealed a characteristic staining of the cytoplasmic cell membrane for all three receptor subtypes. Detailed analysis of two LP samples showed that 65.8%, 4.4%, and 30.5% of CD34(+) cells express CCR-1, CCR-4, and CCR-5, respectively. Culture of LP CD34(+) cells for 24 to 36 hours in the presence of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) resulted in a significant increase in MIP-1alpha receptor expression. TNF-alpha induced MIP-1alpha receptor upregulation in a time- and concentration-dependent manner. Our results suggest that inhibitory cytokines produced by the bone marrow microenvironment are likely to be involved in the regulation of MIP-1alpha receptor expression on hematopoietic cells.
authors.affiliation: CRC Section of Haemopoietic Cell and Gene Therapeutics, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, UK.
authors.forename: J
authors.initials: J
authors.lastname: Dürig
authors.forename: E A
authors.initials: EA
authors.lastname: de Wynter
authors.forename: C
authors.initials: C
authors.lastname: Kasper
authors.forename: M A
authors.initials: MA
authors.lastname: Cross
authors.forename: J
authors.initials: J
authors.lastname: Chang
authors.forename: N G
authors.initials: NG
authors.lastname: Testa
authors.forename: C M
authors.initials: CM
authors.lastname: Heyworth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D001854:Bone Marrow Cells; D002455:Cell Division / Q000187:drug effects; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D019402:Macrophage Inflammatory Proteins / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood; D019707:Receptors, Chemokine / Q000096:biosynthesis* / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D018952:Antigens, CD34; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D019402:Macrophage Inflammatory Proteins; D019707:Receptors, Chemokine; D014409:Tumor Necrosis Factor-alpha; C080633:macrophage inflammatory protein 1alpha receptor; D007371:Interferon-gamma