Immunity-Antibodies And Antigen Essay, Research Paper
There are two different responses produced by the immune response in mammals. There is the “Cell mediated” response, and there is the “antibody response”. First we shall deal with the Cell mediated response. This response is based upon the help of T-Cells. There are various types of T-cells which all have different jobs in the system. The cell mediated response is mainly utilised in defence against intracellular pathogens, such as viri and funghi(and some bacteria). The T-cell precursors are produced in the bone marrow. They move along to the Thymus and become developed T-Cells. T-Cells have a life span of about 5-10 years. T-Cells provide cell mediated immunity. The cell mediated immune system has delayed hypersensitivity, meaning that it takes time for it to get a job done.
T-cells are split into two groupes, phagocytes and lymphocytes. Immuno surveilance is also taken care of by these. Such as if “bad cells”, such as cancerous cells, are discovered in the body they will be terminated.
Then there is the “Antibody response”. This mainly takes care of unwanted bacteria in the body(antibacterial cell response, also known as humoral response). The B-Cell precursor are made in the bone marrow, from stem cells, just like the T-Cells. They move along to Bursa(e.g gut tissue in mammals, e.g. peyers parch). They become developed B-Cells, then turn into plasma cells—–>antibody production. This system works by recognition of own and foreign antigen on cells.
There exists 4 different types of blood groups. There is A,B,AB and O. There are 3 genes involved, O,A and B antigen. Group O has no antigen in red blood cells, A has A antigen, B has B antigen and AB has both A and B antigen. The different antigens can not be mixed. If they are we are confronted with a Graft vs Host reaction. An immune response occurs and the graft will be distroyed if possible, under any circumstances a reaction occurs which can be fatal if a lot of blood of the wrong kind is, e.g., transfused(the blood precipitates). This is a humoral response.The antigen of the graft will be recognised and rejected by the bodys immune system. The ABO markers can be found on most body cells, e.g. in saliva, gastric juice etc.
Tissue in the body also has antigen on it. Therefore when foreign tissue enters a body it will trigger a cell mediated response in order to terminate the foreign tissue. When an organ is to be transplanted into a new body it will have antigen on tissue whoch is different from the one presently in the body, that is unless the organ is being donated from an identical twin. The organ, if possible, will be transplanted from the closest relative(identical twin if possible, if not, then a brother or sister) this is so that the antigen on the organ will be as similar to one of recipent so that the organ will be accepted, and not rejected by the persons body. Often it is not possible to get the necessary organ from a close relative, and an organ is transplanted from a stranger which has no relation to the recipents famile. The antigen on the organ will be different from that of the recipent. Therefore the recipent is treated with immuno-supressing drugs. Patients which have recently had organ transplants are treated with high doses of steroids, such as cyclo sporin. They use these drugs to weaken the immune system so that the organ that has been transplanted is less likely to be rejected by the body of the recipent. One can also gamma eradiate tissue so that the antigen on tissue is destroyed before utilising it, but this can not be done with organs seing as they need to be “live”.