About StemCell Technologies – Immunotrin Kft,.

StemCell Technologies primarily develops and manufactures cell separation technologies based on antibody-coated magnetic beads. In addition,
it offers a range of products for immunology researchers, including solutions for the maintenance of stem cell cultures and specialized culture
media based on methylcellulose or collagen. StemCell products enable the selection of almost all types of white blood cells and their various
maturation stages.

Both positive and negative selection technologies are available for isolating human-derived cells, as well as species-specific cells from rodents
(mice, rats) and other organisms.

Negative selection

In negative selection, unwanted cell types are selectively removed. The antibodies in the magnetic bead cocktail bind to all cells in the suspension—except the target cells—allowing their removal.

Negative selection is recommended when:

binding of the antibody to the target cell would lead
to inhibition or activation, potentially affecting the
outcome of the experiment;
no specific or unique antigen is known for the target
cell.
cell type in case of elimination.

Positive selection

In positive selection, the desired cells are isolated by selectively binding antibodies—attached to magnetic beads—to specific antigens expressed on the surface of the target cells.

Positive selection is recommended when:

the presence of cell-bound antibodies does not interfere
with downstream applications;
high cell purity is required and the population of
unwanted cells is relatively homogeneous (e.g., following
pre-purification by density gradient);
the number of antibodies required for removing
unwanted cells via negative selection would be too high or
unavailable.

Immunodensity/ Gradient Centrifugation

The StemCell immunodensity technique combines the advantages of magnetic bead-based cell enrichment and gradient centrifugation. RosetteSep kits, designed for use with human whole blood, cross-link unwanted cell types with red blood cells present in the sample, forming complexes that can be removed by centrifugation.

During centrifugation on a density gradient (e.g., Ficoll), the red blood cell–unwanted cell complexes sediment, leaving only the desired cells in the "buffy coat" layer. If the sample is not whole blood (i.e., red blood cells are absent) or when isolating mouse- derived cells, a SpinSep reagent is used as a red blood cell substitute.

Advantages of the immunodensity-based cell separation technique:

No magnetic beads or columns are required for separation
Minimal manipulation of the sample; target cells remain
intact
High recovery rates can be achieved.

Magnetic separation

The StemCell magnetic bead-based technique uses specific antibodies bound to magnetic nanoparticles to target either desired or unwanted cells. Separation can be performed either without a column (EasySep methods) or using a column (StemSep methods). In EasySep protocols, cells bound to magnetic particles are placed in a test tube, which is inserted into a magnetic holder. The magnetically labeled cells adhere to the wall of the tube, allowing unlabeled cells to be poured off. The EasySep process can be fully automated using the RoboSep instrument, which labels and separates up to four samples simultaneously.

An alternative approach is the StemSep method, in which magnetically labeled cells are applied to a column placed within a magnetic field. Both techniques use magnetic nanoparticles that are compatible with downstream flow cytometry analysis. Magnetic separation does not interfere with subsequent cell labeling for flow cytometry using direct fluorochrome conjugates (e.g., PE, FITC, APC) or indirect methods (e.g., biotin- streptavidin).

Advantages of immunomagnetic separation:

Cell selection can be automated
Both positive and negative selection strategies are
available

Cell separation spectrum of StemCell

The RosetteSep™ cocktail enables fast and efficient isolation of cells from whole blood with high purity. Utilizing StemCell Technologies’ patented TAC (Tetrameric Antibody Complex) technology, RosetteSep transforms standard density gradient centrifugation into a highly specific, antibody-mediated cell enrichment process. To use, the RosetteSep cocktail is added directly to whole blood.

After a brief room temperature incubation, the mixture is layered over a Ficoll solution. During incubation, the antibodies in the cocktail cross-link unwanted cells to red blood cells, forming immunorosettes. The antibody that binds to the target cell type is intentionally excluded from the cocktail, ensuring that desired cells are not incorporated into the rosettes. Upon density gradient centrifugation, the rosetted unwanted cells pellet to the bottom, while the untouched target cells remain at the plasma–Ficoll interface and can be easily collected.

Key advantages:

Fast – incubation time is only 20 minutes
Simple – enrichment is performed directly from whole blood
High recovery – no loss of target cells during Ficoll separation
High purity – antibody specificity ensures precise separation
Safe – labeling occurs within the sample tube; minimal handling required
Truly negative selection – target cells remain unlabeled and ready for immediate use
Cost-effective – no specialized equipment is needed
Versatile – suitable for both enrichment of target cells and depletion of unwanted cells
Flexible – compatible with the isolation of various cell types

EasySep™ is a column-free magnetic cell separation system that enables both positive and negative selection of cells from human and mousesamples.

Negative selection

The prepared cell suspension is first incubated with the EasySep™ antibody cocktail in a standard FACS tube. After 15 minutes of incubation, dextran-coated EasySep magnetic particles are added to the sample. Following an additional 10-minute incubation, the tube is placed in the EasySep magnet. After 5–10 minutes, the supernatant is carefully poured into a new tube. The magnetically unlabeled target cells are collected in this new tube.

Positive selection

The prepared cell suspension is first incubated with the EasySep™ antibody cocktail in a standard FACS tube. After 15 minutes of incubation, dextran-coated EasySep magnetic particles are added to the sample. Following an additional 10-minute incubation, the tube is placed in the EasySep magnet. After 5 minutes, the supernatant is discarded. The remaining cells in the FACS tube represent the positively selected population, labeled with antibodies and magnetic particles.

Economical – no columns or specialized equipment required
Efficient – high cell purity achieved through the use of magnetic nanoparticles
Fast – entire procedure completed in just 45 minutes

Do it yourself cocktails:

Thanks to the flexibility of TAC (Tetrameric Antibody Complex) technology, any cell-surface antibody can be attached to TAC, enabling the specific binding or depletion of virtually any cell type in a sample. Selection kits compatible with PE-, Biotin-, FITC-, or APC-conjugated antibodies allow the isolation of diverse cell types from various species..

Human, rat, or other non-human mammalian cells can be bound to dextran-coated magnetic nanoparticles via TAC complexes. TAC consists of two mouse IgG1 monoclonal antibodies tetramerized by two rat anti-mouse IgG1 monoclonal antibodies. One mouse antibody binds to the target cell’s surface antigen, while the other binds to the dextran-coated magnetic nanoparticle. The resulting cell suspension is then passed through a stainless steel column placed in a magnetic field.

Negative selection

Unwanted cells are magnetically labeled and retained in the column, while the enriched, unlabeled target cells pass through intact and remain suitable for downstream applications.

Positive selection

Target cells are magnetically labeled and retained in the column, while unlabeled cells continue to flow through. The labeled cells are then eluted from the column. The ultra-small magnetic nanoparticles used are fully compatible with flow cytometry (FACS) and do not interfere with subsequent analyses..

SpinSep™ offers a simple method for obtaining high-purity cells without the need for magnets, columns, or specialized equipment. It combines the specificity of monoclonal antibodies with density gradient centrifugation. Designed to enrich mouse cells from various suspensions—including spleen, bone marrow, and cell cultures—SpinSep enables efficient isolation without requiring red blood cells, unlike the RosetteSep™ system.

In the SpinSep procedure, unwanted cells are labeled with a primary antibody cocktail. After incubation, a secondary antibody conjugated to microparticles is added, which binds to the primary antibodies and forms cross-linked aggregates (immunorosettes) with the unwanted cells. These complexes have increased density, allowing them to sediment during centrifugation through a SpinSep gradient. The target cells, which remain untouched, can then be collected from the interface between the buffer and the gradient.

StemCell Technologies offers multiple SpinSep kits tailored for the isolation of specific cell populations from a variety of mouse-derived tissues.

Quick – no special sample preparation required; following cell isolation from animals, the procedure takes approximately 1 hour
Consistent – yields a homogeneous cell suspension due to antibody-mediated specificity
Truly negative selection – target cells remain unlabeled and are ready for immediate downstream use
Economical – no magnets, columns, or specialized equipment required