Immunology is a branch of biological research strongly oriented toward medical applications. Its subject is the immune system, most particularly that of mammals and humans. Findings and products of immunological research help in infection biology, oncology, allergology, and transplant medicine.
What is immunology?
Immunology is a branch of biological research that is strongly focused on medical applications. Its subject matter is the immune system, most particularly that of mammals and humans. Immunologists study the immune system. The immune system of humans and mammals gives an innate immune response and an adaptive immune response that specifically responds to pathogens and stimuli perceived as foreign. Immunochemistry, immunogenetics, psychoneuroimmunology, immunopathology, and clinical pathology are important subfields of immunology. Immunochemistry has helped to better understand the structure of antigens and antibodies and 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 study disorders of the immune system in sick patients. The spectrum of immunopathologies is wide and ranges from allergies, formation of tumors, rare autoimmune diseases to AIDS. Psychoneuroimmunology is a new field of research that assumes a major influence of the psyche on the immune response.
Treatments and therapies
AIDS, a serious disease of the immune system, occurs because the disease-causing HI viruses attack the T helper cells of the immune system. The job of T-helper cells is to coordinate the immune response and antibody production. The attacked T-helper cells are then absent for the immune response. Instead, they produce new HI viruses themselves. Although the still healthy T-helper cells produce antibodies and memory cells against HIV, they do not prevent the outbreak 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 eventual failure of the immune system. For treatment, patients take many different antiviral drugs. These drugs interfere with different biochemical reactions of the virus replication. The large number of drugs is necessary to prevent the HI viruses from developing resistance. New antiviral drugs are constantly being developed to provide patients with ever better protection against the rapidly mutating HI viruses. In transplantation medicine, the problem is not the sick but the healthy immune system. After an organ or tissue transplant, the patient’s immune system can easily react to rejection. That is why physicians use immunosuppressants to weaken the immune system. Some autoimmune diseases and particularly severe asthma can also be treated with immunosuppressive therapy. However, the health disadvantages are very high: patients carry an increased risk of infection for all kinds of diseases. Malignant tumor cells multiply and spread more easily in the organism, sometimes leading to cancer. Interestingly, these are precisely the side effects of AIDS. For cancer there are also treatment methods coming from immunology. If cancer develops with the weakening of the immune system, the strengthening of 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 are part of immunological research. The annual influenza vaccinations, which are especially recommended for the elderly and people with weakened immune systems, usually contain split vaccines, inactivated parts of the influenza virus envelopes that challenge an immune response without infecting the patient. Just as with the much more dangerous HIV viruses, influenza viruses have a high mutation rate, also known as antigenic drift. That is why affected at-risk groups renew their influenza vaccination annually.
Diagnosis and examination methods
Because the immune system responds to antigen irritation by producing antibodies, detection of specific antibodies that indicate infection by particular pathogens is a common procedure in medical diagnosis. With immunoassays, laboratories routinely detect the presence of antibodies to HIV, hepatitis C, all other types of hepatitis, and cytomegalovirus. Inexpensive screening tests quickly produce a result, but with a not-so-small probability of being falsely positive. If a positive test result is obtained, the doctor will ask for a more elaborate, time-consuming and expensive detection test to remove any doubts about the diagnosis. The pregnancy test strip is also an immunoassay. There are also sports medicine 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 set-up is set up in which the centrifuged blood serum to be tested is brought together with HIV antigens and artificially prepared, biochemically luminescent HIV antibodies. If antibodies are now present in the blood serum, the luminescent signal in the assay diminishes because the artificially prepared antibodies are displaced from their positions on the antigens. Thus, a positive result is obtained. The pregnancy test with strips is a lateral flow test. The basic mechanism here is also a characteristic color change due to antigen-antibody binding: Human chorionic gonadotropin (hCG for short), a peptide hormone, is produced 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 antibodies in the control zone if the result is positive. Medical diagnostics is benefiting greatly from the great surge of development in biotechnology; new devices and methods are appearing in rapid succession. Physicians who are up-to-date in this field read widely and go to international symposia.
