Differentiation of umbilical cord blood-derived multilineage progenitor cells into respiratory epithelial cells

BACKGROUND

Umbilical cord blood (UCB) has been examined for the presence of stem cells capable of differentiating into cell types of all three embryonic layers (i.e. endo-, ecto- and mesoderm). The few groups reporting success have typically confirmed endodermal potential using hepatic differentiation. We report differentiation of human UCB-derived multipotent stem cells, termed multilineage progenitor cells (MLPC), into respiratory epithelial cells (i.e. type II alveolar cells).

METHODS

Using a cell separation medium (PrepaCyte-MLPC; BioE Inc.) and plastic adherence, MLPC were isolated from four of 16 UCB units (American Red Cross) and expanded. Cultures were grown to 80% confluence in mesenchymal stromal cell growth medium (MSCGM; Cambrex BioScience) prior to addition of small airway growth medium (SAGM; Cambrex BioScience), an airway maintenance medium. Following a 3-8-day culture, cells were characterized by light microscopy, transmission electron microscopy, immunofluorescence and reverse transcriptase (RT)-PCR.

RESULTS

MLPC were successfully differentiated into type II alveolar cells (four of four mixed lines; two of two clonal lines). Differentiated cells were characterized by epithelioid morphology with lamellar bodies. Both immunofluorescence and RT-PCR confirmed the presence of surfactant protein C, a protein highly specific for type II cells.

DISCUSSION

MLPC were isolated, expanded and then differentiated into respiratory epithelial cells using an off-the-shelf medium designed for maintenance of fully differentiated respiratory epithelial cells. To the best of our knowledge, this is the first time human non-embryonic multipotent stem cells have been differentiated into type II alveolar cells. Further studies to evaluate the possibilities for both research and therapeutic applications are necessary.

High throughput HLA sequence-based typing (SBT) utilizing the ABI Prism 3700 DNA Analyzer

AIMS AND BACKGROUND

The genetic complexity of the human major histocompatibility complex (MHC) has required the development of various molecular typing methods. The purpose of this paper is to compare the results of two of these molecular methods: sequenced based typing (SBT) and polymerase chain reaction (PCR) using sequence specific primers (PCR-SSP).

METHODS

The SBT method described utilizes an ABI Prism 3700 DNA Analyzer, which has been designed fro high throughput production of sequence data through highly automated operation with significant walk-away time. The ABI Prism 3700 DNA Analyzer is a 96-capillary electrophoresis instrument with the capability of running four 96-well plates black to back in a sixteen-hour period. Potentially, data from this machine can produce Class I sequences for A or B loci for 64 samples in this time frame. The SBT method encompassed exons 2, 3, and 4 with forward and reverse sequence orientation reactions using the PE Biosystems HLA-A and HLA-B Sequenced Based Typing Kits (PE Applied Biopsystems/Perkin-Elmer, Foster City, CA, USA). Most SBT methods previously employed only gather data from exons 2 and 3 which distinguishes most of the polymorphism necessary to identify the majority of alleles in the HLA region. However, in an effort to discern numerous null alleles in the HLA region, exon 4 data is also included. The PCR-SSP method utilized consists of one 96 well tray, with 95 primer mixes and one negative control, per sample designed to produce an intermediate/high resolution HLA-A, B typing.

RESULTS

Data from one 96-well capillary run on the ABI Prism 3700 DNA Analyzer, which consists of results from 16 samples for HLA-A or HLA-B loci, was compared to data derived from sixteen HLA-A and HLA-B PCR-SSP typings. 75% of loci tested achieved a higher resolution HLA typing by the SBT method.

DISCUSSION

The ability to provide allele level HLA typing results can have significant functional implications for the bone marrow transplant community and numerous vaccine studies.