Antigen Testing
Adjuvant Testing
Services Offered
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Antigen Discovery:
Identification of new antigens capable of providing, after immunization, protection against infectious diseases.
An antigen is a substance or molecule that, when introduced into the body, triggers the production of an antibody by the immune system, which will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader.
We are working to discover these new substances. To do so, we employ proteomics and phage display (i.e. we examine a large number of protein antigens by high-throughput screening, such as systems employing mass spectroscopy or lambda phage libraries). In phage display libraries there are billions of phages, with each of them bearing a protein fragment on its surface.
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Antigen Testing:
A novelly discovered antigen must be tested for its ability to induce protection, after vaccination, against infectious diseases. The process of testing is often done in the laboratory (in vitro) using as a sample the serum obtained from an individual immunized with the antigen under study. We examine the serum for the presence of antibodies directed against that antigen. It is important evaluate the quality and not only the quantity of the antibodies induced.
Evaluating the quality of the induced antibodies is the most difficult task. It often involves assessing the portion of the antigen against which the antibody is directed. We can do this easily and rapidly with sera from vaccinated human individuals or animals by using phage displayed libraries. In these library each phage encodes for a small fragment of the antigen. Another way of assessing the quality of the antibodies induced is observing their function.
Fortunately for many diseases we know that a certain antibody function (e.g. ability to kill a microorganisms) correlates with the ability of the antigen to protect the vaccinated individual. When such “protection correlate” is not available we must use a number of alternative means, including in vivo testing. We have a great number of models that enable us to rapidly determine the ability of an antigen to induce protective responses.
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Adjuvant Discovery:
A vaccine is composed not only of a protective antigen, but also of a suitable adjuvant. An adjuvant (from the latin adiuvare or help) is a substance that dramatically increases the amount of antibodies produced after inoculation of the antigen.
Good adjuvants also improve the quality of induced antibodies. Therefore a good adjuvant is as important as a good antigen. The adjuvants acts by stimulating the innate immune system. Charybdis specializes in the study of innate immunity and in identifying the mechanisms of action of adjuvants. Identification of new adjuvant capable of stimulate the immune response using rationale (as opposed to empiric) approaches is a relatively new activity.
In addition to stimulating the innate immune system, adjuvants often act as a depot for the antigen, thereby presenting the antigen over a long period of time and maximizing the immune response before the body clears the antigen. We are working to discover these new substances and to understand their mechanism of action.
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Adjuvant Testing:
it is important to test novel adjuvants for their ability to stimulate the immune response against the antigenic component of vaccines. We test adjuvants for their ability not only to increase the quantity of antibodies induced but also to improve their quality and to increase their diversity.
Moreover we have a number of tools to identify the exact molecules and signal transduction pathways of the immune system that are being activated by a given adjuvant.