CMT: xenotransplanted human stem/progenitor cells in chimeric mice-quantitative

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Xenotransplantation. 2009 May;16(3):145-51.

Quantitative tools for assessing the fate of xenotransplanted human

stem/progenitor cells in chimeric mice.

Cheng K, Gupta S.

Department of Medicine, n Bessin Liver Research Center, Albert Einstein

College of Medicine, 1300 Park Avenue, Bronx, 10461 NY, USA.

BACKGROUND: Identification of transplanted human cells in mouse models is

important for studying the biology and therapeutic potential of stem/progenitor

cells. As stem/progenitor cells are often transplanted in low numbers, detection

of cell engraftment requires sensitive tools. Probes for single copy genes, as

well as repetitive genetic elements are available for detecting transplanted

cells, although their value relative to one another had not been defined.

METHODS: We examined whether human sequences in chimeric mice could be measured

with quantitative real-time polymerase chain reactions for Charcot-Marie-Tooth

disease, type 1 repeat element, sex-determining region Y, or short tandem

repeats (STR) across human leukocyte antigen (HLA) regions, which are distinct

from rodent genomes.

RESULTS: We found that specific probes for all three candidate approaches

successfully identified human cells in mixtures containing human and mouse

genomes. However, probes for Charcot-Marie-Tooth disease element or STRs for HLA

regions were less effective for low numbers of transplanted human

stem/progenitor cells in mice than human sex-determining region on Y-chromosome.

None of the approaches could identify transplanted human cells constituting less

than one percent of the total cell mass. This required localization of

transplanted cells in tissue sections with human-specific in situ hybridization

probes.

CONCLUSIONS: Quantitative assays with probes for single copy gene sequences,

STRs or sex-determining region will be helpful for demonstrating organ

repopulation, although initial lower frequency engraftment of human cells in

chimeric mice will be most effectively identified by complementary tools, such

as in situ localization of human cells in tissues.