S
Sedimentation

The gradual settling down of cells by gravity.

SEM

Standard error of the mean

Sepsis

Severe toxic febrile state resulting from infection with pyogenic microorganisms with or without associated septicemia.

Septicemia

Clinical syndrome characterized by significant invasion of microorganisms from a focus of infection in tissues of the bloodstream.  Microorganisms may multiply in the blood.  Infection of bacterial origin carried through the bloodstream is sometimes referred to as bacteremia.

Shipping

The physical act of transferring a cellular therapy product within or between facilities.  During shipping the product leaves the control of trained personnel at the transporting or receiving facility.

SOP

Standard Operating Procedure

Specificity

The ability to measure (or remove) accurately and specifically the analyte of interest in the presence of other products that may be expected to be present in the sample or product.

Spores

Inactive but viable state of microorganisms in the environment.  Certain bacteria and fungi sustain themselves in this form until the environment is favorable for vegetative growth.  The spore stage is highly resistant to heat, toxic chemicals and other methods of destruction.

Standard Operating Procedures (SOP) Manual

The compilation of written detailed instructions required to perform procedures.

Standards

The current North American edition of Standards for Hematopoietic Progenitor Cell Collection, Processing & Transplantation published by FACT.

Stem cell

The cell attributed to producing all necessary components in a given tissue.

Sterile

Free of microorganisms, including all spores.

Sterile Field

Area that has been prepared and maintained for sterile application with introduction of only other sterile equipment, supplies or reagents.

Sterile Technique

Methods by which contamination with microorganisms is prevented to maintain sterility throughout laboratory procedures.

Sterilization

Process by which all pathogenic and/or nonpathogenic microorganisms, including spores are killed.  This term refers only to a process capable of destroying all forms of microbial life including spores.

STS

Serologic Test for Syphilis

Supernatant

Fluid component in culture system; liquid portion of cells in suspension.

Surgically Clean

Mechanically cleansed but not sterile.  Items are rendered surgically clean by the use of chemical, physical or mechanical means that markedly reduce the number of microorganisms on them.

Syngeneic

Hematopoietic progenitor cells obtained from a genetically identical donor (e.g. identical twin).

T
T cells or T lymphocytes

One of the two major classes of lymphocytes.  The T cell antigen receptor is present on the cell-surface and is composed of two chains.  A given T cell may possess an alpha and a beta chain or a delta and a gamma chain.  T cells are of two major subtypes, CD4+ with helper activity and CD8+ with cytotoxic effector activity.  T lymphocytes are thought to be the prime mediators of GVHD when contained in the donor inoculum and residual host derived T cells can mediate graft rejection.  The most common form of cell purging performed in the CPL lab is the removal of T lymphocytes from the donor graft prior to transplantation.