Immunologists are researching the immune system. The immune system of humans and mammals gives a innate immune response and an adaptive immune response that reacts specifically to pathogens and as externally perceived stimuli. Immunochemistry, immunogenetics, psychoneuroimmunology, immunopathology and clinical pathology are important areas of immunology.
Immunochemistry has helped to better understand the structure of antigens and antibodies as well as the biochemical aspects of immune responses. The detection of antibodies is important in the diagnosis of infections. Antibodies are also used as markers in immunohistochemistry. Immunogenetics deals with the genetics of genetic autoimmune diseases such as type I diabetes, rheumatoid arthritis, Crohn's disease or multiple sclerosis. Immunopathology and clinical immunology investigate disorders of the immune system in sick patients.
The spectrum of immunopathologies is wide and ranges from allergies, tumors, rare autoimmune diseases to AIDS. Psychoneuroimmunology is a new field of research that assumes a great influence of the psyche on the immune defense.
AIDS, a serious disease of the immune system, arises because the disease-causing HI viruses attack the T helper cells of the immune system. The role of T helper cells is to coordinate immune response and antibody production. The affected T helper cells are then missing for the immune response.
Instead, they produce new HI viruses themselves. Although the healthy T helper cells produce antibodies and memory cells against HIV, they do not prevent the onset of AIDS. The HI viruses in the body mutate very quickly and are no longer recognized by the antibodies. The result is a weakening and ultimately the failure of the immune system. Patients take many different antiviral drugs for treatment. These drugs intervene in different biochemical reactions of virus replication. The variety of remedies is necessary to avoid a resistance development of HI viruses.
New antiviral drugs are constantly being developed that protect patients from the rapidly mutating HI viruses. In transplantation medicine, the problem is not the sick but the healthy immune system. Following organ or tissue transplantation, the patient's rejection reactions are likely to occur. Therefore, medics use immunosuppressants to weaken the immune system. Also, some autoimmune diseases and particularly severe asthma can be treated with an immunosuppressive therapy. However, the health disadvantages are very high: the patients carry an increased risk of infection for all sorts of diseases.
Malignant tumor cells multiply and spread more easily in the organism and sometimes lead to cancer. Interestingly enough, these are also the side effects of AIDS. For cancer there are also coming from immunology treatment methods. When the weakening of the immune system causes cancer, strengthening the immune system helps to cure cancer. Cancer immunotherapy refers to the treatment of cancer with active immunization by cancer vaccines and passive immunization by vaccinating antibodies. Vaccinations belong to immunological research.
The annual flu shots, especially recommended for the elderly and immunocompromised people, usually contain split vaccines, which are inactivated parts of influenza virus envelopes that challenge an immune response without infecting the patient. As with the much more dangerous HI viruses, influenza viruses have a high mutation rate, also known as antigenic drift. Therefore, affected risk groups renew the flu vaccine annually.
Since the immune system responds to antigenic challenge with the formation of antibodies, the detection of specific antibodies indicative of infection by certain pathogens is a common method of medical diagnosis. With immunoassays, laboratories routinely detect the presence of antibodies to HIV, hepatitis C, all other types of hepatitis and cytomegalovirus.
Low-cost addiction tests quickly lead to a result that is falsely positive with a not very small probability. If a positive test result is obtained, the physician will ask for a more elaborate, time-consuming and expensive diagnostic test to clear up the diagnosis.
The pregnancy test strip is also an immunoassay. There are also sports medical immunoassays for the detection of doping substances or other drugs. The HIV test is an ELISA immunoassay (enzyme-linked immunosorbent assay). For this purpose, a test arrangement is set up in which the centrifuged blood serum to be tested is brought together with HIV antigens and artificially prepared, biochemically bright HIV antibodies. Now, if antibodies are present in the blood serum, the flare signal in the assay decreases, because the artificially prepared antibodies are displaced from their positions on the antigens. So it comes to a positive finding.
The strip pregnancy test is a lateral flow test. The basic mechanism here is also a characteristic color change by an antigen-antibody binding: The human chorionic gonadotropin (short: hCG), a peptide hormone, arises in the placenta and indicates pregnancy. On the test strip, hCG binds to labeled hcG antibodies. This complex migrates on the test strip and eventually stains anti-Fc antibody in the control zone if the result is positive.
Medical diagnostics profited greatly from the great development spurt in biotechnology; new devices and methods appear in quick succession. Doctors who are up to date in this area read a lot and go to international symposia.