Scope of immunology
Immunology is a biologic science devoted to studying the development and function of the cellular and humoral components of the immune system by which the body reacts to expel, destroy, or neutralize foreign substances and organisms, including pathogens. It is concerned with the processes by which these components interact as well as the mechanisms that control their function in health and disease.
Immunology consists of three major subdivisions:
- Immunochemistry is dedicated to studying the chemical nature of antigens, antibodies, and their interactions.
- lmmunobiology includes those aspects of immunology related to the biologic functions of the cell and tissue components of the immune system.
- Serology is the study of immune reactions mediated by antibodies or immunoglobulins present in the serum. The most important serologic reactions described are agglutination, precipitation, complement fixation, and cytotoxicity. Serologic reactions have had wide applications in blood grouping, tissue typing, diagnostic microbiology, and medicine.
Immunologic techniques and reactivity have diverse application in biology and medicine.
- Diagnostic microbiology and clinical medicine. Diagnostic microbiology uses a variety of immunologic methods and reactions to study the host's immune responses to microbial pathogens. It is useful it, diagnosing bacterial infections such as typhoid fever and brucellosis, as well as viral, fungal, and spirochete (syphilis) infections. Immune reactions are also used to diagnose a variety of clinical disorders such as plasma cell neoplasms (i.e., multiple myeloma) and immunodeficiencies (congenital or acquired). Furthermore, antibodies are used extensively for measuring hormones and drugs in serum and urine by radioimmunoassay.
- Blood transfusion serology: This specialty represents the study and characterization of red cell antigen‑antibody systems (ABO, Rh) and the application of immunologic methodology for blood typing, performance of compatibility (cross‑matching) tests, and diagnosis of hemolytic disorders (congenital or acquired).
- Tissue typing and histocompatibility testing: Various serologic techniques are used to detect and characterize antigenic determinants coded by histocompatibility s Such testing is important for donor selection, especially in kidney and bone marrow transplantation. Other diagnostic uses involve diseases influenced by genes linked to the major immunogene complex.
- Forensic medicine: Immunologic tools are frequently used in forensic science laboratories to assist in solving cases of doubtful paternity (blood grouping), stain identification (e.g., blood and semen stains), milk and meat testing (e.g., to distinguish horse meat from other meats), arid so on.
- Clinical laboratory immunology: Immune-based therapies are being introduced at an accelerating rate and assessments of complex immune-based therapies are having an increasing impact on the responsibilities of the clinical immunology laboratory. Protein chemistry contributed electrophoresis. Immunologists contributed immunoelectrophoresis and monoclonal antibodies. Immunogeneticists and collaborating engineers brought forth flow cytometry. Many contributed to the huge advances in quantitative immunochemical methodologies. Autoimmune diseases, allergy and asthma, organ and bone marrow transplantation, lymphoid and plasma cell malignancies, and primary and secondary immune deficiencies, have all provided challenges and opportunities to advance clinical laboratory immunology.