An antigen is a molecule recognized by the immune system. At the molecular level, an antigen is characterized by its ability to be "bound" at the antigen-binding site of an antibody. Immunogenicity is the ability to induce a humoral and/or cell-mediated immune response. Antigenicity is the ability to combine specifically with the final products of the immune response(i.e. secreted antibodies and/or surface receptors on T-cells). Although all molecules that have the property of immunogenicity also have the property of antigenicity, the reverse is not true. Antigens are usually proteins that are too large to bind as a whole to any receptor, only specific segments that form the antigen bind with a specific receptor. Such segments are called epitopes.A linear or a sequential epitope is an epitope that is recognized by antibodies by its linear sequence of amino acids, or primary structure. In contrast, more antibodies recognize a conformational epitope that has a specific three-dimensional shape and its protein structure. Design and select a suitable antigen is a key to produce antibodies for various applications.

ChinaPeptides has the antigen technology and advanced equipment, can provide customers with: (1) Protein expression and purification in prokaryotic system; (2) Peptide synthesis and conjugation.

• The original nucleoprotein express
• Yeast protein expression
• Mammalian cell protein expression
• Insect cell protein expression
• Protein purification services
• Protein markers service