Glossary

Find definitions and explanations of technical terms used
throughout this website

Adoptive immunotherapy

Adoptive immunotherapy is based on infusing a patient with extra functioning immune cells grown from his/her own body (autologous cell therapy) or taken from a donor (allogeneic cell therapy). In the fight against cancer, allogeneic cell therapy offers something the conventional autologous approach cannot: the potential to treat large numbers of patients using a standardized, off the shelf therapeutic product.

Allogeneic

Derived from a genetically different donor. Cellectis’ gene-editing technologies allow us to create allogeneic CAR T-cells, meaning they are derived from healthy donors rather than the patients themselves.

Autologous

Derived from part of the same individual.

Biotechnology

The OECD defines biotechnology as “the application of science and technology to living organisms, as well as parts, products and models thereof, to alter living or non-living materials for the production of knowledge, goods and services.” Biotechnology, or “biological technology” in full, is a cross between biology – the study of life – and a range of technological breakthroughs from specific disciplines such as microbiology, biochemistry, biophysics, genetics, molecular biology, computer science, and more.

CAR

CARs or Chimeric Antigen Receptors are engineered molecules that, when present at the surface of T-cells, enable them to recognize specific proteins or antigens that are present on the surface of other cells. These receptors are typically used to graft the specificity of an antibody derived from a single cell, or a monoclonal antibody, onto a T-cell and provide it with a specific targeting mechanism to seek, identify, interact with and destroy the tumor cells bearing a selected antigen associated with that tumor also known as the tumor-associated antigen, or TAA.

CTA

In Europe, the Clinical Trial Application (CTA) filing is the regulatory step consisting in submitting the required study documentation package to the health authority to obtain the authorization to perform clinical investigation.

DNA

DNA is a molecule that occurs in every living cell. It contains all the information necessary for an organism to develop and function. It is also the basis of heredity in that it is passed on, either partially or in full, during reproduction. The genetic blueprint carried by DNA constitutes an organism’s genome.

DNA sequencing

Invented in the second half of the 1970s, DNA sequencing involves determining the sequence of the nucleotides in a given DNA fragment. The DNA sequence contains all of the information a living organism needs to survive and reproduce. DNA sequencing can be used in medicine to identify, diagnose and possibly find cures for inherited or acquired genetic diseases. In biology, the study of DNA sequences has become a key tool, for example, in detecting defective genes.

Drug candidate

After identification of a new potential target, a product candidate or drug candidate is developed based on compounds with strong therapeutic potential.

Electroporation

Or electropermeabilization, is a microbiology technique in which an electrical field is applied to cells in order to increase the permeability of the cell membrane, allowing chemicals, drugs, RNA or DNA to be introduced into the cell.

EMA

The European Medicines Agency (EMA) is a European Union agency whose main responsibility is the protection and promotion of public and animal health, through the evaluation and supervision of medicines for human and veterinary use.

Endonuclease

An endonuclease is a type of nuclease. Nucleases cut nucleic acids into shorter fragments. Endonucleases can cut through the center of a polynucleotide chain, as opposed to exonucleases which only cleave nucleotides from the ends of the chain.

Enzyme

Enzymes are proteins that speed up (catalyze) reactions inside organisms while themselves remaining unchanged and without altering the substances taking part in the reaction. Without enzymes, certain basic biological reactions would not happen fast enough. Enzymes enable new substances to be synthesized so that cells can form and grow (anabolism). They also help break substances down to provide the body with energy (catabolism).

FDA

The Food and Drug Administration (FDA) is a federal agency of the United States Department of Health and Human Services, responsible for protecting and promoting public health, including through the regulation and supervision of biopharmaceuticals.

Gene

A gene is a segment of DNA that provides the blueprint for making some part of a living organism. DNA is the basic constituent of chromosomes, by which all creatures pass on their hereditary traits from parent to offspring. The stretch of DNA that makes up a gene is itself composed of nucleotides. There are 4 types of nucleotides, abbreviated as follows: A (for adenine), T (for thymine), G (for guanine), and C (for cytosine).

Genome

A genome is the full genetic make up of an individual or species, encoded in its DNA (except for certain viruses which genome is carried by RNA molecules). The genome provides the layout for how cells should function and how hereditary traits should be passed down from one generation to the next. It contains all the coding sequences of DNA (which are transcribed via messenger RNA and translated into proteins) as well as the non coding sequences (which are not translated).

GMP

Good Manufacturing Practices (GMP) are a set of regulations applicable to the manufacturing of health products, especially medicines intended for human use, such as UCART product candidates for example. A company is required to comply with GMP regulations, in order to be granted from governmental regulatory agencies, its license to manufacture pharmaceutical products.

GvHD

Graft-versus-host disease (GvHD) is a complication which follows an allogeneic tissue transplant, consisting in immune cells in the graft recognizing the recipient as "non-self" and attacking its cells.

Homologous recombination

A genetic recombination event between two identical sequences located on two different DNA molecules or separated from each other on the same molecule.

IND

In the U.S., the Investigational New Drug (IND) filing is the regulatory step consisting in submitting the required study documentation package to the health authority to obtain the authorization to perform clinical investigation.

Knock-in

In molecular biology, a knock-in is the introduction of a gene of interest into a given locus. After homologous recombination, the gene of interest is controlled by the target gene’s promoter and regulatory sequences and is therefore synthesized in lieu of the target gene.

Knock-out

In molecular biology, a knock-out (or KO) is the complete inactivation of a gene. Knock-out is generally used when performing research on mammalian model species, such as mice or rats, or on human cell lines.

Lentivirus

Lentivirus is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in man and other mammalian species. The best known lentivirus is the Human Immunodeficiency Virus HIV, which causes AIDS.

Lymphocyte

Lymphocytes are a type of white blood cell. As part of the immune system, they play a major role in defending the body against infection. They are produced in the bone marrow and circulate through the bloodstream and lymphatic tissues (spleen, lymph nodes).

There are two main types of lymphocyte: B cells and T cells. The difference between them is both molecular (they bear different receptors on the surface of the cell) and functional (B lymphocytes produce antibodies while T lymphocytes kill or organize the fight against abnormal or infected cells.

Lymphodepletion (via chemotherapy)

Lymphodepletion is a medical procedure in which certain immune cells are eliminated, e.g. via chemotherapy, to prevent the body from rejecting a transplant of engineered T cells.

Meganucleases

Meganucleases are "molecular DNA scissors" that can be used to replace, remove or modify sequences in a highly targeted way. These proteins are the perfect tools for genome engineering because they are specific enough to home in on and splice a single site per genome. meganucleases are used to modify all genome types and open up wide avenues for innovation, particularly in the field of human health (for example by removing viral genetic material or "repairing" damaged genes) and in agricultural biotechnology. meganucleases can be found in many organisms, such as archaea (also archaebacteria), bacteria, phages, fungi, yeasts, algae and certain plants.

Nuclease

An enzyme capable of catalyzing nucleic acids—RNA (ribonucleic acid) and DNA (deoxyribonucleic acid)—into nucleotides and various components of these nucleic acids. They cut between two nucleotides in a nucleic acid strand.

Nucleotide

A nucleotide is a basic component of DNA and RNA. It is a molecule composed of a sugar (ribose or deoxyribose), one to three phosphates and a nucleobase, also known as a nitrogenous base. Certain nucleotides combine to form the basis of DNA and RNA, while others are cofactors or coenzymes.For DNA, there are four different nucleotides, each with a different nitrogenous base:

- dAMP, a purine, which nitrogenous base is adenine (A)

- dGMP, a purine, which nitrogenous base is guanine (G)

- TMP, a pyrimidine, which nitrogenous base is thymine (T)

- dCMP, a pyrimidine, which nitrogenous base is cytosine (C).

Product candidate

After identification of a new potential target, a product candidate or drug candidate is developed based on compounds with strong therapeutic potential.

Protein

This is one of the most important types of molecules and is present in all living organisms and viruses. Proteins perform essential cellular functions, such as the formation of cell architecture and the modulation of cell activity. Proteins are macromolecules that are composed of long chains of amino acids (basic building blocks) and come in various forms, such as enzymes, hormones, receptors and neurotransmitters. Proteins are built from the genetic information contained in a gene.

RNA (ribonucleic acid)

RNA is a biological molecule that occurs in virtually all living organisms, including some viruses. Chemically, it is very closely related to DNA. In fact, RNA is synthesized inside cells by copying DNA strands. Living cells use RNA especially as a messenger to convey genetic information so that our genes can make the proteins they need. RNA may also fulfill a number of other functions, taking part in many chemical reactions at the cellular level, for example.

T-cell

A T-cell, or T lymphocyte, is a type of white blood cell that helps trigger immune responses. T-cells find and destroy foreign pathogens such as bacteria and viruses, but they will also attack the body’s own cells if those cells have undergone abnormal (e.g. cancerous) transformations.

TALENĀ®

TALEN® is designed by fusing the DNA-cutting domain of a nuclease to TALE domains, which can be tailored to specifically recognize a unique DNA sequence. These fusion proteins serve as readily targetable “DNA scissors” for gene editing applications that enable us to perform targeted genome modifications such as sequence insertion, deletion, repair and replacement in living cells.

TALEN® is a registered trademark owned by the Cellectis Group.

UCART

UCART (Universal Chimeric Antigene Receptor T-cells) are “off-the-shelf” allogeneic product candidates, whose production can be industrialized and thereby standardized with consistent pharmaceutical release criteria, over time and from batch to batch.