This compilation of abbreviations and terms is provided to help interpret the topic material. This is also a valuable resource when investigating the primary literature cited in the FAQ's and Recommended Articles.

Abbreviations/Words

Meaning

Aa

Amino Acid

Ab

Antibody

Adhesion Molecules

Membrane-expressing molecules that mediate two cells to interact, e.g., a stem cell and a cells within a microenvironment such as stroma. An adhesion molecular can also mediate an interaction between thel cell and the extracellular matrix proteins.

Adipose cells

Fat cells in the bone marrow

Ag

Antigen

AGM

Aorta-gonads-mesonephros: Site LHSC in the embryo.

Angiogenesis

The growth and sprouting of additional blood vessels from pre-existing blood vessels

AML

Adult Myeloid Leukemia

Anoikis

Apoptosis, induced by anchorage-dependent cells detaching from ECM

APC

Antigen Presenting Cell

Asymmetric Division

One daughter cell quiescent and the other proliferating and moving away from site of division

Altered Nuclear Transfer (ANT)

The adult cells is engineered to switch off a gene to prevent the developed embryos from implanting. Thus, the method does not allow for cloning of a person. The Cdx2 gene has been targeted to test proof of principle.

Autophagy

Self-eating cells: Delivery of cytoplasmic constituents such as whole organels to the lysosome for degradation. Occurs during starvation, aging and development. It is a recycling process.

BFU-E

Erythrocyte Burst Forming Unit (Early erythroid progenitors)

Bipolar Stem Cell

The cell can form two lineages

Blastocyte (or blastula)

4-5 day embryo formed prior to implantation in the uterus. Is comprised of a hollow mass of only a few undifferentiated stem cells.

Blastomere

Single cells taken from 8-cell embryos

BM

Bone Marrow

Bp

Base pair

BSA

Bovine Serum Albumin

CD

Cluster Designation: Used with a number to indicate a cell surface marker.

CD33

Present on committed progenitors in the myeloid lineages.

CD34

Present on Lymphohematopoietic stem cells and their progenitors. Express at high densities in the most primitive cells and become dim as the cells mature towards differentiation.

CD38

Not detectable on Lymphohematopoietic stem cells but begin to appear as the cells commit towards a lineage.

CD133

Also referred as Prominin. A marker of LHSC and perhaps NSCs

Cell Release

Movement of bone marrow cells out of the sinus into the peripheral circulation.

CFU

Colony Forming Unit

CFU-E

Erythrocyte Colony Forming Unit (Late stage erythrocyte progenitors)

CFU-GM

Granulocyte-Macrophage Colony Forming Unit

CFU-S

Colony Forming Unit- Spleen

Chemoattractant

A factor that attract a cell, e.g., a cytokine or a chemokine

Chemotaxis

Attraction of a cell to an area where there is a gradient increase of a particular factor

CLP

Common Lymphoid Progenitor

CMP

Common Myeloid Progenitor

CNS

Central Nervous System

Cloning

The method of desilencing genes in adult specialized cells by proteins in an egg (oocyte). The technique entails removing the nuclei material from an egg and replacing with the genetic material from the specialized cells.

cRNA

Complementary RNA

CSF

Colony stimulating factors: Generally referred to groups of cytokines and other growth factors that can stimulate Lymphohematopoietic stem cells and bone marrow progenitors. (In general, they are the hematopoietic stimulators)

CXCR, CXC

Chemokine receptor

Cytokines

A family of small labile molecules that seem functionally redundant. They are mostly naturally glycoprotein and are important in regulating the maturation of bone marrow stem cells.

Da

Dalton (kDa: kilodalton)

Differentiation

Downward steps towards the development of mature immune and blood cells

De-differentiation

Backward movement of differentiated cells to immature types.

DC

Dendritic Cells

Definitive LHSC

Pre-definitive LHSC

Functional migrating cells that can home to the bone marrow and repopulate the host.

De-silence or retro-differentiation

The method to re-express all genes in adult specialized cells. This could be in form of cloning or iPS.

DNA

Deoxyribonucleic acid

dsDNA

Double-stranded DNA

Diapedesis

Transendothelial migration

EC

Endothelial Cells

EGC

Embryonic Germ Cells

Endoderm

The extra-embryonic tissue that gives rise to the visceral

and parietal endoderm. It diverges from the inner cell mass to form the outer layer of the embryo.

Ensoulment

When an embryo attain a soul

EPC

Endothelial Progenitor Cells or Adult Angioblasts

Epigenetic

Alterations in gene-expression patterns, without changes in DNA sequence. This could occur by modification of proteins that surround the genomic DNA, e.g.,

Epigenetic Inheritance

Transmission of non-DNA sequence via meiosis or mitosis.

  - Euchromatin

DNA open and available

  - Heterochromatin

DNA not available

Epimorphic Regeneration

Amputation and full regeneration from a stump

Epo

Erythropoietin (a hormone that stimulate erythropoiesis)

Erythropoiesis

Development of red blood cells

ETP

Early T-lineage Progenitor

ELP

Earliest Rag+ lymphocyte progenitor

Extravasation

Movement of a cell in or out of the bone marrow through endothelial barrier. Chemotaxis cannot account for this type of movement.

Extravascular Compartment

Areas in the bone marrow microenvironment that are not blood vessels

ECM

Extracellular matrix: Fibronectin, collagen etc.

Excreted from stromal cells and regulate functions in bone marrow, in particular, LymphoHematopoietic Stem Cells

Embryonic carcinoma

A type of testicular cancer that maintains the potential to give rise to mature tissues.

EPC

Endothelial Progenitor Cell

ES

Embryonic Stem Cell

hESC (NIH definition)

“Cells that are derived from the inner cell mas of blastocyt stage human embryos, are capable of dividing without differentiating for a prolonged period in culture, and are known to develop into cells and tissues of the three germ layers”

Extramedullary

Outside the bone marrow

FACS

Fluorescence-activated cell sorter

Fetal Microchimerism

Following pregnancy, a few fetal cells persist in the mom’s body for long periods of time, even decades.

FITC

Fluorescein isothiocyanate (Use to tag other proteins (e.g., antibodies) for immunofluorescence)

FL

Fetal Liver

FCS

Fetal Calf Sera

FSC

Forward Scatter

G-CSF

Granulocyte colony stimulating factor: Used to mobilize bone marrow in the periphery and to differentiate granulocyte precursor to neutrophils.

GM-CSF

A cytokine: Granulocyte-Macrophage colony stimulating factor: Growth factors for Lymphohematopoietic stem cells.

GMP

Granulocyte/macrophage progenitor

Genomic Imprinting

The expression of a gene depending on which parental allele is expressed.

Haploinsufficiency

Expression of  one allele is repressed. This could be caused by knockdown or mutation of one allele. This leads to reduced level of a particular protein or levels.

Harvesting

Collecting bone marrow cells for transplantation

Hematopoiesis

Formation of 8 distinct lineages from a Lymphohematopoietic Stem Cell (LHSC)

Heterokaryon

The fusion of two cells resulting in two nuclei.

Hemato-lymphoid system

Reference to the hematopoietic system to include both the lymphoid and myeloid compartments

Hgb

Hemoglobin

HLA-DR

Hluman Histocompatibility Leukocyte Antigen-DR (analogous to MHC-Class II)

HME

Hematopoietic/Bone Marrow Microenvironment

Homing

A cell when transplanted, goes to a particular site through specific, e.g., if a Lymphohematopoietic stem cells given intravenously goes directly to the bone marrow and forms its niche in the area of stromal cells.

Homokines

Dual role of a factor as a hormone and as a cytokine

HUVEC

Human Umbilical Vein Endothelial Cells

IPs

Induced pluripotency, the method by which genes are expressed in adult cells to generate ESC-like cells

IFN

Interferon

iPS

Inducible Pluripotent Stem Cells: A method to insert genes to desilence adult stem cells to functional ESCs

Interleukins

A growing family of cytokines. To date there are 22 members in the family.

Intramedullary

Inside the bone marrow

Intravascular Compartment

Blood vessels within the bone marrow microenvironment

IVF

In vitro fertilization

LHSC (sometimes referred as HSC)

LymphoHematopoietic Stem Cell

Lin (-)

When several antibodies are used to deplete committed progenitors. The remaining cells are lineage negative (Lin -).

Lymphohematopoietic (LHSC): General

Bone Marrow System that generates immune and blood cells.

LHSC (human)

In general: CD34+/Lin -

LHSC (mouse)

Sca1+/s-kit+/Lin-

LN

Lymph node

Loss of Heterozygosity (LOH)

The allele is duplicated into the homozygous causing overexpression of the gene.

LTC-IC

Long term culture initiating cells assay (To study primitive bone marrow progenitors)

LT-HSC

Long-term hematopoietic stem cell

Lymphopoiesis

Development of lymphoid cells: T-cell, B-cells, NK cells and Dendritic cells, DC (only if NK and DC cells are formed from the lymphoid lineages)

Mature

Usually referred to the differentiated cells of hematopoietic lineages.

M-CSF

Monocyte-Colony Stimulating Factor

Megakaryocyte

Cells of myeloid lineage that differentiate into platelets

MEP

Megakaryocyte/erythrocyte progenitor

Mesengenic Process

The genesis of mesordermal tissues, such as bone, cartilage, muscle, marrow stroma, tendon, fat, dermis and connective tissues. This process occurs in adults as well as in embryos.

Mesoderm

The middle germ layer of the developing embryo that occupies an intermediate position between the ectoderm and the endoderm, and forms the skeleton, muscles and connective tissue.

MHC-Class I

Major Histocompatibility Complex, Class I: Expressed on all cells.

MHC-Class II

Major Histocompatibility Complex, Class II: Expressed on bone marrow Lymphohematopoietic stem cells, antigen presenting cells, mesenchymal stem cells, activated T-cells

Microenvironment

The structures, cells, factors (e.g., ECM), nerve fibers etc that comprise the bone marrow/hematopoietic system.

Migration

Cells that move from one site to the other, in the absence of a known chemoattractant.

MK

Megakaryocyte

MLR

Mixed Lymphocyte Reaction

MΦ

Macrophage

MNC

Mononuclear Cells

Mobilization

Injecting a chemoattractant to move stem cells from the bone marrow into the periphery.

Monopotent

A bone marrow progenitor that has matured but is committed towards one lineage.

Morula

Spheroidal mass of cells from early cleavage divisions of the zygote.

MPP

Multipotent Progenitor

mRNA

Messenger RNA

MSC

Mesenchymal Stem Cell

Multipotent

A multipotent cell can self-renew but can only form cells of one germ layer, e.g. hematopoietic stem cells.

Mulitpotent is also used to determine a committed cell, which is close in maturation to a pluripotent cell (e.g., hematopoietic stem cell), but can form less lineages. Thus, a multipotent cell has less potential to survive for a long period as compared to a pluripotent stem cell. These types of cells are considered as `cell in transition’.

Myelopoiesis

Lineages distinct from the lymphoid lineages.

Niche

Stabilization of a cell in a particular microenvironment and area of the bone marrow.

NK

Natural Killer cells

NSC

Neural Stem Cell

Nuclear Transfer

The removal of nucleus from a donor cell and transfer to an egg in which its nuclear DNA has been removed. The resulting embryos will match the donor and not the host. 

Oct4

Octamer Binding Factor: Important in ES and prevents differentiation.

Ontogeny

Development of Lymphohematopoietic System

Parous

Has given birth at least once

Parthenogenesis

Embryonic development from oocyte in the absence of spermatozoon. Lack potential for full-term delivery; Suggested for therapies.

PBMC

Peripheral Blood Mononuclear Cells

Pericyte

This is an old terminology. Currently, these cells might be the recently defined mesenchymal stem cells.

Polycomb

Protein family linked to maintaining stable and heritable

repression of several genes.

Pluripotency

A self-renewing cell that has the capability to commit toward different cell lineages of at least two of the three germ layers: endoderm, ectoderm and mesoderm.

E.g., ESCs, which can form all cell lineages of the body, including germ cells are pluripotent cells.

PMN

Polymorphonuclear Cells (e.g., neutrophils)

Precursor

The stage of lineage just before the differentiated cell.

Preimplantation genetic diagnosis (PGD)

The method is used in in vitro fertilization. A blastomere is removed at the 8-cell stage for genetic testing before implantation.

PGD/HLA testing

Done with the intent of knowing the type of CB for use in a diseased sibling, refer as PGD/HLA testing type 1.

PGD/HLA testing type 2

Primitive LHSC

Cells cannot home to the bone marrow and repopulate a host. Needs to undergo maturation on stromal cells and cytokines.

Reticular Cell

Non-descript cells in the bone marrow that have not been characterized. Sometimes fibroblasts and mesenchymal stem cells are referred as reticular cells.

RNA

Ribonucleic Acid

Sca-1

Stem Cell Antigen-1

SCID

Severe Combined Immundeficiency

SSEA

Stage-specific embryonic antigen

SH-2, -3, -4

Markers developed by Osiris Biotechnology to detect mesenchymal stem cells.

SH-2 has the specificity as for CD105 (endoglin) and SH-4 for stro-1

Sinus

Marrow sinus: Area of the blood vessels where the arterial and venous blood mix. Mature hematopoietic cells and other bone marrow cells exist through the sinus into the peripheral circulation.

Spln

Spleen

SRC

SCID repopulating cells

SSC

Side Scatter

Stochastic

Random

Stroma

The supporting layer of hematopoiesis in bone marrow

ST-HSC

Short-term hematopoietic stem cell

Syncytium

The formation of multinucleated giant cells. These could be naturally occurring fusion, eg., during development to form bone, muscle and placenta.

Synkaryon

After cell-cell fusion, the emergence of a single nucleated cell. A heterokaryon is formed as an intermediate step. The heterokaryon will have both nucleus. A classical example is the formation of hybridoma.

TBI

Total Body Irradiation

TdT

Terminal deoxynucleotidyltransferase

TERT

Telomerase reverse transcriptase (hTERT = human…)

Teratoma

Tumors containing cells from the three primary germ layers; A benign tumor; Can develop into teratocarcinoma

TF

Transcription Factor

Tg

Transgenic

TGF-

Transforming Growth Factor

Therapeutic Cloning

The method is similar to cloning of a mammal, except that the newly formed ESCs are used to generate specialized cells for transplantation in a diseased model. The advantage is the formation of autologous cells, which will eliminate rejection.

TNF-

Tumor Necrosis Factor-

Totipotent

Unlimited potential to differentiate into cells of the three germ layers, germ cells and extra-embryonic cells such as plancent. Thus, in this definition, only blastomeres are totipotent cells since ESC, in vitro cannot produce these cells.

TPO

Thrombopoietin

Trabeculae

Soft bones in the marrow compartment

Transdifferentiation 1

A stem cell of one germ layer forming cells of another germ layer, e.g., a mesodermal stem cells forming specialized ectodermal cells.

Transdifferentiation is also used in reference of cells of one lineage forming cells of another lineage, e.g., lymphoid cells forming myeloid type cells.

Transdifferentiation 2

Stem cells in one organ forming differentiated cells of another organ, e.g., bone marrow stem cells forming hepatocytes.

Traffic

Trafficking or circulation of cells refer to the movement of cells out of the bone marrow and through the periphery. The cells might return to the bone marrow.

Translocation

Breaking part of a chromosome to another chromosome, e;g., bcr-abl oncogene formed by translocation, t(9:22) as seen in chronic myeloid leukemia (CML).

Trophoectoderm

The outer layer of the blastocyst.

UCB

Umbilical Cord Blood

Vasculogenesis

Formation of primitive vascular networks from endothelial progenitors.

Veto Cells

Cells that induce apoptosis in effector cells such as CD8+ T-cells, through the recognition of the disparate MHC antigens.

Mesenchymal stem cells have been reported to exert veto functions. As third party stem cells, they can suppress allogeneic responses between T-cells from different donors.

vWF

von Willebrand Factor (a marker of endothelial cells)

YS

Yolk Sac

Zygote

Diploid cell of fusion between male and female gametes at fertilization.