Sample Management Services and Precautionary Practices required to maintain functional and identity integrity of the specimens associated with each of these services:
Blood (Body fluid) Sample Processing to Isolate Lymphocytes (Cells)
Three options offered for Lymphocyte isolation from whole blood: Differential centrifugation are thru:
b) Lymphocyte Separation Medium (LSM) or
c) in Leuko-prep tubes.
The RBCs pellet down while lymphocytes are suspended as "Buffy Coat" between the LSM and plasma or between the gel of the Leuko-prep tube and the plasma. Plasma can be removed from the top and saved for testing. The buffy coat consisting of Peripheral blood mononuclear cells (PBMCs) can then be removed by gentle suction with a pipette. Cells are then washed and used for further processing, analysis or for cryo-preservation.
Techniques for removal of macrophages and monocytes from PBMCs also involves plating of cells in tissue culture flasks coated with human AB serum overnight. The monocytes attach to the surface and other lymphocytes are removed by pipetting out the rest of the cell suspension.
Enriched B cell or T-cell populations are obtained by negative selection with antibody coated magnetic bead system. Fractionated cell populations are used for cellular analyses or a variety of cell culture experiments including those requiring infections of different human virus types.
These tasks are usually initiated by the client at the time of receipt of samples or shipping out or testing an aliquot of serum sample, other body fluid, culture supernatants with growth factors, toxins, antibodies, vaccines or solutions with biological polymers or agents.
We make sure that
1. The vials to be used for aliquoting are:
• can withstand low temperatures of up to minus100°C for a minimum of 10 years and
• Are impermeable to LN2 for samples to be stored in liquid phase of LN2.
2. Caps for these tubes are provided with a rubber leak proof seal ring.
3. Use digital print-labeling device that can be linked to a desktop computer and can generate regular print labels, bar-coded labels or a combination of both.
4. Labels that are cold resistant and capable of sticking to frozen vials
The print portion of the sample labels is secured with a transparent tape part which renders labels impervious to water and stable
in -70oC storage as well as in liquid phase nitrogen storage.
For long term storage in liquid nitrogen, peripheral blood mononuclear cells (PBMCs) and cell culture cells are cryopreserved in cryopreservation medium. Cryopreservation and thawing SOPs have been developed to yield 95% cell viability on revival of such cells. SOP have also been developed and used for cryopreservation of biological fluids (serum, plasma, other body fluids) and cell culture supernatants