Objective:Conventional myeloid cell staining methodologies were employed to stain splenocytes and peripheral blood cells by fixation and permeabilization and non-fixation and permeabilization methods,respectively,and effects of staining were compared following flow cytometry detection.Methods:Peripheral blood and spleen of three 8-week-old C57 male mice were divided into fixation and permeabilization group and non-fixation and permeabilization group for staining,and flow cytometry was used to detect mean fluorescence intensity(MFI)of each fluorescent antibody and proportion of positive cells.Results:In mouse peripheral blood samples,MFI of 7-AAD-PerCP-Cyanine5.5 and CD147-PE were lower in fixation and permeabilization group than non-fixation and permeabilization group,MFI of F4/80-FITC,MHC Class Ⅱ(I-A/I-E)-APC-R700,Ly-6c-APC-Cy7,CD206-BV421,CD45-BV510,CD11b-BV605,CD11c-BV650 and CD86-BV786 were higher than non-fixation and permeabilization group.Proportions of each immune cell in fixation and permeabilization group and non-fixation and permeabilization group were highly similar.In mouse spleen samples,MFI of antibodies in fixation and permeabilization group were higher than those in non-fixation and permeabilization group,with exception of CD147-PE,which had a lower MFI than non-fixation and permeabilization group;proportions of dendritic cells and Mon/Ly-6clow cells were lower than non-fixation and permeabilization group,whereas proportions of rest myeloid subpopula-tions were higher than non-fixation and permeabilization group.Conclusion:Fixation and permeabilization in peripheral blood cells can improve antibody MFI,but it has little effect on proportion of positive cells.Fixation and permeabilization can enhance antibody MFI in splenocytes,while effect on proportion of each positive cell is more significant.It is advised that when designing staining strate-gies,researchers attempt to choose alternative cell surface antigens for assay or optimize protocols through required pre-experiments in order to acquire stable and dependable results.

AIM:Flow cytometry was used to evaluate the effects of short-term storage conditions(fresh,frozen at-80℃for 7 d,and stored at 4℃for 7 d)on the median fluorescence intensity(MFI)of antibodies and the percentage of immune cell subsets in mouse peripheral blood mononuclear cells(PBMCs)and splenocytes.METHODS:The PBMC and splenocyte suspensions from six male Kunming mice were collected and analyzed under three different processing con-ditions to compare differences in the antibody MFI and percentages of monocyte subsets(Ly-6clow/Ly-6cmedium/Ly-6chigh),macrophages(M1/M2),and dendritic cells.RESULTS:Both tissue and antibody specificity were demonstrated by changes in the antibody MFI values.Following storage at-80℃,the MFIs of certain antibodies(such as CD45 and F4/80 in PBMCs,and CD115,Ly-6c,F4/80,CD80 and MHC-II in the spleen)were similar to those of the fresh groups,where-as after storage at 4℃,the MFIs of other antibodies(such as 7-AAD,CD115,Ly-6c and MHC-II in PBMCs,and CD11b,CD206 and CD11c in the spleen)were closer to those of the fresh groups.The MFI of most of the examined anti-bodies varied significantly following storage.Both storage conditions significantly reduced the viability of PBMCs and sple-nocytes.In PBMCs stored at 4℃,the percentages of total monocytes,Ly-6cmedium/Ly-6chigh monocytes,total macrophages,and dendritic cells were similar to those in the fresh group.Compared with the fresh group,both storage groups presented significantly lower percentages of M1 macrophages and dendritic cells(P<0.05).There were no statistically significant differences in the percentages of total monocytes,Ly-6cmedium monocytes,Ly-6chigh monocytes,total macrophages,M1 and M2 macrophages,or dendritic cells in the spleen among the three groups(P>0.05).The percentage of Ly-6clow monocytes did not differ substantially(P>0.05)between the fresh and-80℃frozen groups but was significantly lower in the 4℃storage group than in the fresh group(P<0.05).CONCLUSION:The storage conditions of the samples had a substantial effect on the flow cytometry results(antibody MFI and cell subset percentages)of the PBMCs and splenic cells,with tissue specificity.If the percentage of immune cell subgroups(particularly monocytes/macrophages/dendritic cells)in PBMCs is highly important,storage at 4℃for 7 d is preferable.If the MFI values of specific antibodies(such as CD45 and F4/80)are important,freezing at-80℃may be more appropriate.If the MFI values of most antibodies or the percentages of criti-cal subgroups(such as total monocytes/Ly-6chigh/total macrophages/dendritic cells)in splenic cells need to be close to those of fresh samples,4 ℃ storage for 7 d is more effective.Freezing at-80℃is preferable if the MFI values of particular anti-bodies(such as CD115 and Ly-6c)need to be determined.

AIM:Flow cytometry was used to evaluate the effects of short-term storage conditions(fresh,frozen at-80℃for 7 d,and stored at 4℃for 7 d)on the median fluorescence intensity(MFI)of antibodies and the percentage of immune cell subsets in mouse peripheral blood mononuclear cells(PBMCs)and splenocytes.METHODS:The PBMC and splenocyte suspensions from six male Kunming mice were collected and analyzed under three different processing con-ditions to compare differences in the antibody MFI and percentages of monocyte subsets(Ly-6clow/Ly-6cmedium/Ly-6chigh),macrophages(M1/M2),and dendritic cells.RESULTS:Both tissue and antibody specificity were demonstrated by changes in the antibody MFI values.Following storage at-80℃,the MFIs of certain antibodies(such as CD45 and F4/80 in PBMCs,and CD115,Ly-6c,F4/80,CD80 and MHC-II in the spleen)were similar to those of the fresh groups,where-as after storage at 4℃,the MFIs of other antibodies(such as 7-AAD,CD115,Ly-6c and MHC-II in PBMCs,and CD11b,CD206 and CD11c in the spleen)were closer to those of the fresh groups.The MFI of most of the examined anti-bodies varied significantly following storage.Both storage conditions significantly reduced the viability of PBMCs and sple-nocytes.In PBMCs stored at 4℃,the percentages of total monocytes,Ly-6cmedium/Ly-6chigh monocytes,total macrophages,and dendritic cells were similar to those in the fresh group.Compared with the fresh group,both storage groups presented significantly lower percentages of M1 macrophages and dendritic cells(P<0.05).There were no statistically significant differences in the percentages of total monocytes,Ly-6cmedium monocytes,Ly-6chigh monocytes,total macrophages,M1 and M2 macrophages,or dendritic cells in the spleen among the three groups(P>0.05).The percentage of Ly-6clow monocytes did not differ substantially(P>0.05)between the fresh and-80℃frozen groups but was significantly lower in the 4℃storage group than in the fresh group(P<0.05).CONCLUSION:The storage conditions of the samples had a substantial effect on the flow cytometry results(antibody MFI and cell subset percentages)of the PBMCs and splenic cells,with tissue specificity.If the percentage of immune cell subgroups(particularly monocytes/macrophages/dendritic cells)in PBMCs is highly important,storage at 4℃for 7 d is preferable.If the MFI values of specific antibodies(such as CD45 and F4/80)are important,freezing at-80℃may be more appropriate.If the MFI values of most antibodies or the percentages of criti-cal subgroups(such as total monocytes/Ly-6chigh/total macrophages/dendritic cells)in splenic cells need to be close to those of fresh samples,4 ℃ storage for 7 d is more effective.Freezing at-80℃is preferable if the MFI values of particular anti-bodies(such as CD115 and Ly-6c)need to be determined.

Objective:Conventional myeloid cell staining methodologies were employed to stain splenocytes and peripheral blood cells by fixation and permeabilization and non-fixation and permeabilization methods,respectively,and effects of staining were compared following flow cytometry detection.Methods:Peripheral blood and spleen of three 8-week-old C57 male mice were divided into fixation and permeabilization group and non-fixation and permeabilization group for staining,and flow cytometry was used to detect mean fluorescence intensity(MFI)of each fluorescent antibody and proportion of positive cells.Results:In mouse peripheral blood samples,MFI of 7-AAD-PerCP-Cyanine5.5 and CD147-PE were lower in fixation and permeabilization group than non-fixation and permeabilization group,MFI of F4/80-FITC,MHC Class Ⅱ(I-A/I-E)-APC-R700,Ly-6c-APC-Cy7,CD206-BV421,CD45-BV510,CD11b-BV605,CD11c-BV650 and CD86-BV786 were higher than non-fixation and permeabilization group.Proportions of each immune cell in fixation and permeabilization group and non-fixation and permeabilization group were highly similar.In mouse spleen samples,MFI of antibodies in fixation and permeabilization group were higher than those in non-fixation and permeabilization group,with exception of CD147-PE,which had a lower MFI than non-fixation and permeabilization group;proportions of dendritic cells and Mon/Ly-6clow cells were lower than non-fixation and permeabilization group,whereas proportions of rest myeloid subpopula-tions were higher than non-fixation and permeabilization group.Conclusion:Fixation and permeabilization in peripheral blood cells can improve antibody MFI,but it has little effect on proportion of positive cells.Fixation and permeabilization can enhance antibody MFI in splenocytes,while effect on proportion of each positive cell is more significant.It is advised that when designing staining strate-gies,researchers attempt to choose alternative cell surface antigens for assay or optimize protocols through required pre-experiments in order to acquire stable and dependable results.