TY - JOUR
T1 - Comparison of sample fixation and the use of LDS-751 or anti-CD45 for leukocyte identification in mouse whole blood for flow cytometry
AU - Maes, Melissa L.
AU - Davidson, Lisa B.
AU - McDonagh, Paul F.
AU - Ritter, Leslie S.
PY - 2007/1/30
Y1 - 2007/1/30
N2 - Flow cytometry methods used to measure leukocyte function often entail sample preparation procedures that cause artifactual cell activation. To avoid leukocyte activation by isolation techniques, some preparation methods use fluorescent markers to discriminate leukocytes from erythrocytes in whole blood. One of these markers, laser dye styryl-751(LDS-751), has been used to distinguish leukocytes by staining nucleic acid, but has been found to stain other blood cells and dead cells indiscriminately. Thus, LDS-751 may not be an appropriate reagent for leukocyte identification in whole blood. Fixing samples with formaldehydes increases cell permeability and causes surface protein cross-linking that may alter staining of both intra- and extracellular markers. The degree of this sample alteration by formaldehyde fixation, however, remains in question. In addition, little is known about flow cytometry and sample preparation methods in mouse whole blood. The purpose of this study was to determine if labeling leukocytes with a monoclonal antibody specific to leukocyte common antigen (CD45) was superior to labeling with LDS-751 and to determine the effect of sample fixation on a mouse whole blood preparation for flow cytometry. Samples were incubated with CD16/CD32 Fc receptor blocker, and either 10 μg/ml LDS-751 or phosphate buffered saline (PBS). The samples were then fixed with paraformaldehyde or diluted with PBS followed by incubation with 5 μg/ml PerCP-conjugated anti-CD45, 5 μg/ml FITC-conjugated anti-CD11b, or 80 μM dichlorofluorescein diacetate. We found that samples labeled with LDS-751 demonstrated decreased fluorescence intensity for granulocyte CD11b expression and ROS production compared to samples labeled with anti-CD45. In addition, sample fixation decreased mean fluorescence intensity in samples labeled with either LDS-751 or anti-CD45. We conclude that labeling leukocytes with monoclonal antibody CD45 in a mouse whole blood preparation is preferable, as it provides improved measurement of leukocyte indices compared to LDS-751. Also, while sample fixation prior to antibody staining caused a decrease in overall fluorescence; it can be used to successfully identify extra-cellular markers.
AB - Flow cytometry methods used to measure leukocyte function often entail sample preparation procedures that cause artifactual cell activation. To avoid leukocyte activation by isolation techniques, some preparation methods use fluorescent markers to discriminate leukocytes from erythrocytes in whole blood. One of these markers, laser dye styryl-751(LDS-751), has been used to distinguish leukocytes by staining nucleic acid, but has been found to stain other blood cells and dead cells indiscriminately. Thus, LDS-751 may not be an appropriate reagent for leukocyte identification in whole blood. Fixing samples with formaldehydes increases cell permeability and causes surface protein cross-linking that may alter staining of both intra- and extracellular markers. The degree of this sample alteration by formaldehyde fixation, however, remains in question. In addition, little is known about flow cytometry and sample preparation methods in mouse whole blood. The purpose of this study was to determine if labeling leukocytes with a monoclonal antibody specific to leukocyte common antigen (CD45) was superior to labeling with LDS-751 and to determine the effect of sample fixation on a mouse whole blood preparation for flow cytometry. Samples were incubated with CD16/CD32 Fc receptor blocker, and either 10 μg/ml LDS-751 or phosphate buffered saline (PBS). The samples were then fixed with paraformaldehyde or diluted with PBS followed by incubation with 5 μg/ml PerCP-conjugated anti-CD45, 5 μg/ml FITC-conjugated anti-CD11b, or 80 μM dichlorofluorescein diacetate. We found that samples labeled with LDS-751 demonstrated decreased fluorescence intensity for granulocyte CD11b expression and ROS production compared to samples labeled with anti-CD45. In addition, sample fixation decreased mean fluorescence intensity in samples labeled with either LDS-751 or anti-CD45. We conclude that labeling leukocytes with monoclonal antibody CD45 in a mouse whole blood preparation is preferable, as it provides improved measurement of leukocyte indices compared to LDS-751. Also, while sample fixation prior to antibody staining caused a decrease in overall fluorescence; it can be used to successfully identify extra-cellular markers.
KW - CD11b
KW - Flow cytometry
KW - LDS-751
KW - Mouse
KW - Neutrophil
KW - Paraformaldehyde
KW - Reactive oxidative species
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U2 - 10.1016/j.jim.2006.10.016
DO - 10.1016/j.jim.2006.10.016
M3 - Article
C2 - 17187818
AN - SCOPUS:33846240409
SN - 0022-1759
VL - 319
SP - 79
EP - 86
JO - Journal of Immunological Methods
JF - Journal of Immunological Methods
IS - 1-2
ER -