Antibodies are the warriors inside our body. They are part of our immune system, recognising and fighting against bad foreign invaders, called antigens. Antibodies can bind to a broad range of antigens, and are produced by cells of the immune system, known as B-cells. To learn more about antibodies and antigens, watch this video. Antibodies can be used for medical and diagnostic applications, in the form of monoclonal antibodies. So, what are monoclonal antibodies? The word monoclonal means a single clone. Monoclonal antibodies are identical antibodies produced in laboratories from a single clone of immune cells. The cloned immune cells are genetically completely identical. And so the antibodies they produce are also identical to one another. Which is perfect – to work properly, we need large numbers of identical antibodies. Monoclonal antibodies have a high specificity, which means they can recognize and bind to a single antigen binding site.
This means they are targeted to a specific antigen, and is a key trait that makes them useful in diagnosing and treating diseases. So how are they produced? Well first off we need an immune system. Which is why we use mice. In a laboratory, a mouse is vaccinated with the target antigen. This stimulates the B-cells, found in the spleen, to produce antibodies against the target antigen. The spleen of the mouse is then removed. The B-cells in the spleen are isolated, and fused with a tumour cell. We need to fuse the antibody producing b cells with a tumour cell, because the b-cells don’t have the ability to divide. BUT tumours however do divide easily. This fusion cell is called a Hybridoma cell. The hybridoma cells reproduce rapidly to make cloned cells, which all make the same antibody. These monoclonal antibodies are collected and purified, ready for use. They match up perfectly with the target antigens in the body.
And are made in huge quantities. Monoclonal antibodies are potentially really exciting, and can be used in a number of ways… I bet you didn’t know antibodies were used in pregnancy tests!! Monoclonal antibodies on the pregnancy test stick bind to the HCG hormone found in the urine of pregnant women causing a colour change. Monoclonal antibodies can target the antigens on cancer cells and be used in a number of ways… Firstly, by combining them with an anti-cancer drug which can then accurately locate and target only the cancer cells or avoiding the healthy cells.
Secondly for detection… they can carry special markers which show doctors where the cancerous cells are starting to build up. Thirdly, they can be used to trigger the body’s own immune system to recognise and kill the cancer cells They can also be used to identify other diseases, and locate blood clots. So those are a few uses… but are they all good? We’ve seen the positives, so what are some criticisms? They are expensive and time consuming to produce… they have more side effects than expected; and they are too specific meaning that whilst yes they can diagnose and attack diseases, they only can attack one type each time. A more diverse and adaptable solution would be better. The potential power of monoclonal antibodies is clear. They are not yet as widely used as everyone hoped when they were first developed, but scientists are working hard to make them better and safer for wider use.
Their journey is just beginning!!