NR AXOO
AU Holada,K.; Simak,J.; Vostal,J.G.
TI Expression of Cellular Prion Protein (PrPc) Affects Survival of Red Blood Cells in Mice
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.04
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB Documented transmissions of vCJD by blood transfusion underline the need of better insight in blood prion protein biology. One of key unknown remains physiological function of PrPc. PrPc is expressed on CD34+ hematopoietic stem cells and its expression is regulated during blood cell differentiation. Human as well as mouse red blood cells (RBC) express approximately 200 PrPc molecules / cell (Holada et al., BJH 2000, 110, 472-80). To test if the PrPc expression plays a role in the survival of RBC we carried out transfusion study in mice. RBC isolated from blood of wild type (WT) and PrP knockout (KO) FVB mice were labeled "in vitro" by different levels of NHSbiotin. The labeling was optimized to allow simultaneous detection of both populations of RBC in mouse blood using flow cytometry. To exclude the influence of different level of cell biotinylation on the experiment outcome two mixtures of RBC were prepared. The first contained KO RBC labeled with high and WT RBC with low level of biotin and the second mixture contained cells labeled "vice versa". Each mixture was injected via tail vein in a group of WT mice (n=5) and the survival of RBCs was followed. Samples were analyzed on day 1, 2, 3, 6, 9, 15, 21 and 29. Simultaneously the expression of PrPc on RBC was monitored using flow cytometry with MAb 6H4. KO RBC displayed significantly higher first day post-transfusion recovery compared to WT RBC in both groups of mice (81 ± 3 % vs. 74 ± 3 %, P<0.005 and 90 ± 4 % vs. 80 ± 4 %, P<0.005). The slope of the RBC survival curve in all individual mice during the initial 15 days was steeper for KO RBC (mavg = -3.44) than for WT RBC (mavg = -2.37) suggesting the protective role of PrPc in circulating RBC. The difference in the slope diminished during the 15 to 29 day period which was accompanied by a 50% decrease of PrPc surface expression on transfused WT RBC. Our data suggest that PrPc expression plays role in the post-transfusion recovery and survival of RBC. The observation that WT RBC disappear from the circulation at lower rate than KO RBC until their level of surface PrPc reaches 50% is compatible with the protective role of PrPc expression on cells. Taken together our study demonstrates that physiological role of PrPc expression on RBC may lay in facilitating their longer survival in circulation. (GACR 310/04/0419, MSMT 0021620806).
AD K. Holada, 1st Faculty of Medicine, Charles University, Institute of Immunology and Microbiology, Czech Republic; J. Simak, J.G. Vostal, Center for Biologics Evaluation and Research, FDA, Division of Hematology, USA
SP englisch
PO Schottland