Antibodies And B Cells Similarities

Lymphocytes are found in the blood stream and at sites of infections but are found in two different forms that have many similarities and differences. They are both a type of white blood cell and are formed from stem cells (Toole and Toole 2008) but then mature into different cells known as T lymphocytes (T cells) and B lymphocytes (B cells). T cells mature in the thymus with cell surface molecules TCR and CD3 and release lymphokines, whereas, B cells mature in the bone marrow with cell surface molecules of antibodies and BCR. This is one way of distinguishing between the two types of cell (Eales, 1999). Even though they both specifically recognise foreign molecules such as microorganisms and destroy them, also known as a specific immune response, …show more content…
Antibodies are Y-shaped protein molecules, also known as immunoglobulin, which are produced by B lymphocytes. They’re specifically made to identify and neutralize foreign molecules such as bacteria, fungi and parasites. Antibodies are passed from the mother to the foetus during pregnancy, this is known as passive immunity, but then further develop when the infant is born. It is most common that antibodies are created in response to a certain antigen, however, the immune system does produce natural antibodies that aren’t in response to immunisation or vaccination but to carbohydrates on the surface of bacteria which is the beginning of an immune response. Antibodies respond to a pathogen in three main ways. Firstly, they may bind directly to the pathogen which prevents the pathogens from entering or causing damage to other cells. Antibodies can also stimulate other cells in the immune system to destroy the pathogen. Opsonisation can also be used to mark the pathogens. Phagocytes and the pathogens both have a negative charge so naturally repel one another. The antibody binds to the pathogen and neutralises the charge on the pathogen so that the phagocyte won’t be repelled and therefore it is easier for the phagocyte to engulf the pathogen to then neutralise it with enzymes (Holdener et al, 1999). The antigens on the surface of the pathogen are taken up by B cells which then present the antigens on their cell surface. T helper cells attach to the antigen and activate other B cells to divide also by mitosis, the same as the T cells, however, B cells divide into different types of cells. Eales (1999) suggested that during mitosis of B cells, the sequence of amino acids in the daughter cells may not be exactly the same as the parent cell, but this does not alter which antigen the antibody recognises. The overall affinity of the antibodies generally increases over time as the B cell numbers increase