Anti-peptide antibodies as a diagnostic tools

Scientific Director: M.-Pilar Marco
Scientific Coordinator: Nuria Pascual

Industrial gap/problem covered

Development of anti-protein antibodies is often very expensive, and in some cases the protein is not available as an antigen. In these cases it is better to identify peptide fragments (usually 10 to 20aa long) from target proteins to use as haptens and thus generate anti-peptide antibodies. In other cases, this strategy is used because peptide antibodies minimize potential cross-reactivity between structurally homologous proteins.

Description

A successful anti-peptide antibody depends on several factors such as peptide sequence selection, peptide synthesis, peptide-carrier protein conjugation and the design of the antibody development protocol.

Peptide sequence selection is likely the most difficult and critical step in the development of anti-peptide antibodies.The real challenge in producing useful anti-peptide antibodies is to choose peptides that are not only antigenic but which also generate an antibody that bind to the native protein. In the design and selection of peptides there are many factors that have to be taken into account.

These peptides have to be antigenic and the peptide sequence should correspond to a region of the protein that is exposed and accessible when the protein is folded into its native conformation.In our peptide selection process each peptide antigen considered is measured against several databases to confirm the epitope specificity, ultimately finding the best candidate peptides with the antigenicity and solubility suitable for antibody production.

Examples of projects founded in competitive calls are:

• NanoCardioCoco (IPT-2011-1337-010000): The objective of this project is to develop two biosensors: one applied to pneumococcus disease and the other to cardiovascular diseases.
• InmunoQS (SAF2015-67476-R): The goal of the ImmunoQS project is to advance the knowledge of the mechanisms involved in the pathogenesis caused by two important microorganisms (Pseudomonas aeruginosa and Staphylococcus aureus) with aim to develop and accelerate an early diagnosis of infectious diseases caused by these pathogens, through immunochemical studies of their Quorum Sensing (QS) systems as therapeutic and biomarker targets.
• CIBER BBN intramural projects: QS-Profile (Immunochemical Diagnostic Strategies based on the Quorum Sensing System), CARDIOGRAFET (Disposable sensing platform based on graphene-SGFET to monitor biomarkers for cardiac diseases), COLOCOMB (Combinatory and targeted nanomedicines for the treatment of advanced colorectal cancer), Magneto-NH (Multiplexed determination of pathogenic bacteria in sepsis by novelImmunoassay), NATRIP (Disposable microsensor for direct detection of B-type Natriuretic Peptides by surface conductivity measurements) and OligoCODEs (A universal diagnostic platform based on oligonucleotide codified nanoparticles and DNA micrarray sensor devices)

An example of our anti-peptides strategy is explained in this  publication: Pastells, C.; Acosta, G.; Pascual, N.; Albericio, F.; Royo, M.; Marco, M. P., An immunochemical strategy based on peptidoglycan synthetic peptide epitopes to diagnose Staphylococcus aureus infections. AnalyticaChimicaActa 2015, 889, 203-211.

Services involved:

Projects are carried out by  U2 (CAbS) and U3 (Peptide Synthesis) Units. These two platforms are currently collaborating on projects of this type. Sequences to be immunized are designed and discussed together. After that, unit U3 performs the synthesis and purification of the selected peptides. Later the rest of the project is developed by unit U2.

• Design and Selection of Peptides for raising antipeptideantibodies (U2 U3)
• Peptide synthesis (U3)
• Peptideconjugation (U2)
• Antibody design protocol and development (monoclonal or polyclonal antibodies) (U2)

• U2
• U3

CAbS is managed by the scientific team of the Nb4D group (Nb4D) with high expertise in hapten synthesis, conjugation and antibody production.We have an extensive track record of successful projects in developing polyclonal and monoclonal antibodies against small molecules and peptidesfor the development of diagnostic tools. These include, for example, the evaluation of carcinogenic processes, cardiovascular diseases, and infectious diseases.

Peptide synthesis platform is managed by the UQC-PCB group with strong experience on peptide synthesis. We have high experience on regular (10 to 20 aa), cyclic and modified post-translational (phosphorylated, acetylated, methylated, derivatized with fatty acids, sugars among others) peptides developed as antigenic peptides for antibody production. Together with CAbS we have developed anti-peptides antibodies as diagnostic tools or to be used in a screening process for cardiovascular, neurological and infectious diseases.