5.5 antibodies

• antibodies are proteins with specific binding sites synthesised by B cells
• each antibody has two identical binding sites
• antibodies are made up of four polypeptide chains
• each antibody has a specific binding site that fits onto a specific antigen which forms an antigen-antibody complex
• the binding site is different on different antibodies so its known as the variable region
• the constant region binds to receptors on cells such as B cells
• monoclonal antibodies can be used to target specific substances and specific cells