Detecting Iodine-Labeled Cells

Cell Staining

When labeled antibodies are used to detect antigens in cells or tissues, several characteristics of an antigen can be readily determined. Most importantly, cell staining will show both the presence and subcellular localization of an antigen. Double-labeling techniques permit the simultaneous detection of two antigens, allowing comparisons of the relative distribution of different antigens. Many cell-staining methods can also be used in conjunction with conventional histological stains and autoradiographic methods to compare the localization of the antigen with other markers. Cell staining can also be used in pathology studies for determining such variables as the type of infectious organism, the progenitor of a neoplastic cell, or the presence of an inflammatory response. With certain modifications, the procedure can be used to purify cells on the basis of the antigenic composition of their cell surface. Cell staining is a versatile technique and, if the antigen is highly localized, can detect as few as a thousand antigen molecules in a cell or tissue. In some circumstances, cell staining may also be used to determine the approximate concentration of an antigen. Improvements in antibody labeling methods, microscopes, cameras, and image analyzers are rapidly extending the sensitivity of cell-staining procedures and are making these techniques more quantitative. Even without these improvements, cell staining can yield important qualitative and semiquantitative data. This introduction describes protocols for cell staining techniques and includes a discussion of major constraints, antibody selection, and troubleshooting.

Fixing and Binding Antibodies to Suspension Cells in Preparation for Staining

Staining of suspension cells after fixation, described here, is normally used only to detect cell-surface antigens. Once cells are fixed and permeabilized, the antibodies are added. The antibodies can be labeled directly or they can be detected by using a labeled secondary reagent that will bind specifically to the primary antibody. Detection reagents for cell staining can be labeled with fluorochromes, enzymes, gold, or iodine. Because the cells are in suspension, the washing steps are tedious, and care should be taken not to centrifuge for long durations or at high speeds.

In vitro facilitating role of polygonatum sibiricum polysaccharide in osteogenic differentiation of bone marrow mesenchymal stem cells from patients with multiple myeloma

BACKGROUND

Bone marrow mesenchymal stem cells (BMMSCs) were proved to play a vital role in multiple myeloma (MM). Polygonatum sibiricum polysaccharide (PSP) was found to have anti-tumor pharmacological effects, yet its interaction with BMMSCs remained poorly understood. Therefore, we explore the effect of PSP on osteogenic differentiation of BMMSCs.

METHODS

BMMSCs were isolated by density gradient centrifugation. CD90 and CD34 were detected by flow cytometry (FCM). Osteogenic marks were detected by quantitative real-time PCR (qRT-PCR) and Western blotting (WB). The vitality of cells treated with different concentrations of PSP was observed by Cell Counting Kit-8 (CCK-8). ALP staining kit was used to detect the activity of alkaline phosphatase (ALP). Alizarin red staining detected the formation of mineralized nodules. Osteoblast-associated genes were evaluated by qRT-PCR and WB. The phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) signaling pathways were tested by WB.

RESULTS

The BMMSCs showed good growth under an inverted microscope. FCM showed that CD34 and CD45 was low-expressed, whereas CD44, CD90 and CD105 was highly expressed. Compared with the Control group, the expressions of Runx2 and ALP in cells were significantly increased. CCK-8 showed that different concentrations of PSP had no significant effect on the viability of BMMSCs. BMMSCs treated with 25 mg/l PSP were stained the most deeply by ALP. Mineralized nodules in PSP groups dramatically increased, and hit a peak under the action of 25 mg/l PSP. PSP up-regulated p-PI3K, p-AKT, and p-mTOR, but had no significant effect on PI3K, AKT, and mTOR.

CONCLUSION

PSP induced osteogenic differentiation of BMMSCs from MM patients.

Binding Antibodies to Attached Cells or Tissues in Preparation for Staining

Cells for staining are usually prepared from one of three sources: adherent cells, suspension cells, or whole tissues. Antibodies generally are applied directly to the area of the cells or tissues that is being studied. The antibodies can be labeled directly or they can be detected by using a labeled secondary reagent that will bind specifically to the primary antibody. Detection reagents for cell staining can be labeled with fluorochromes, enzymes, gold, or iodine.