Glossary ADCC (antibody-dependent cellular cytotoxicity)
An immune reaction in which cells of the immune system actively kill diseased cells that have previously been labeled as "sick" by specific antibodies.

Affinity
The strength of binding of an antibody to its target molecule.

Affinity maturation
In vivo: a process by which specialised immune cells with the highest affinity for a disease-related target are selected for survival and proliferation in the course of an immune reaction.
In vitro: a biotechnological process to engineer antibodies towards higher affinities than that of the original antibody molecule.

Antibody
A defined class of proteins generated by the immune system to neutralise and attack foreign material such as bacteria or viruses as well as own diseased cells.

CDC (complement-dependent cytotoxicity)
A mechanism by which antibodies with a Fc region, together with other factors in the blood called complement, bind to the surface of diseased cells such as cancer cells and punches holes into their membranes leading to cell death.

CDR (complementarity-determining region)
Defined, small region of antibodies that is responsible for the tight binding of antibodies to target molecules.

Fab (fragment, antigen binding)
An antibody fragment with a molecular weight of about 50 kDa retaining the binding activity of a full length antibody. This fragment is composed of one complete light chain (VL-CL) combined with the variable domain and the first constant region of one heavy chain (VH-CH1).

Fc part (fragment, constant)
The constant region of full length antibodies that is not involved in binding of the target molecule, but mediates other effector functions of antibodies such as ADCC and CDC.

Framework
The stable, rather invariant scaffold of the variable domain of an antibody. It is indispensable for the antigen-specific binding since it provides the support for the CDRs.

Glycosylation
The process of adding sugar units to a molecule.

Immunogenicity
The immunogenicity of a drug describes whether the drug is recognised by the immune system as foreign, and how strong a rejection reaction of the body against this drug is or will be. Drugs with high immunogenicity are usually excluded from further clinical development because of unwanted side-effects and/or rapid elimination from the body`s circulation.

In-vitro
"In-vitro" originally means "in a glass". Before applying drug substances to humans, they need to be carefully characterised in the laboratory, i.e., outside living organisms.

In-vivo
In contrast to “in-vitro” the application to and characterisation of substances in living organisms is termed “in-vivo” (“in the living”).

KD (dissociation constant)
The measure of the binding strength of an antibody to a target molecule. A typical KD for a strong binding event is 10-9 moles/liters. The smaller the value, the stronger the binding.

kDa (kilodalton)
A unit describing the molecular weight of chemical/biological compounds. One kilodalton corresponds to a thousand grams per mol of the compound.

Monovalent binding
The binding of an antibody to a target molecule via a single contact region.

PENTRA® antibody fragment
Antibody fragment generated by using Delenex proprietary set of human antibody frameworks.

scFv (single-chain fragment, variable)
A small antibody fragment (about 25 kDa) which retains the binding activity of a full length antibody. A scFv is a fusion protein consisting of the variable regions of the heavy and the light chain of an antibody (Fv fragment) both linked by a flexible polypeptide chain.

Target molecule
A molecule of the human body or of bacteria and virus that plays a crucial role in a disease and that is recognised by an antibody or other drugs. Recognition of the target molecule by a drug triggers events in the human body that eventually modify, relieve or cure diseases.