Essential Microbiology & Immunology Terms
Sterilization:
Destroying all microorganisms existing in any substrate.
Chemotherapeutic Agents:
Antimicrobial agents used effectively to combat infectious microbes.
Pasteurization:
Used to eliminate most microorganisms from foods.
Disinfectants:
Kill microorganisms that cause disease but do not necessarily destroy all forms (like spores).
Antiseptics:
Substances used to kill or inhibit the growth of microbes present on skin or wounds.
Selective Toxicity:
Ability to kill or inhibit disease-causing microbes without damaging host tissues.
Antibiotics:
Chemical substances produced by the metabolism of some bacteria, filamentous fungi, and actinomycetes.
Sulfonamides:
A group of substances that interfere with certain metabolic reactions in pathogenic microbes, inhibiting their growth.
Vaccination:
Involves injecting dead or weakened microbes (or parts of them) of a disease one wants to prevent. These microbes activate the immune system (SI), leading to the formation of specific antibodies and generating active immunity.
Serotherapy:
Treating patients suffering from an infectious disease with antibodies specific to the antigens of the microorganisms causing the disease.
Primary Immune Response:
Occurs upon the first contact with a specific antigen.
Secondary Immune Response:
Occurs when the immune system detects the same antigen a second time. This response is faster and stronger than the primary response, with less delay between antigen entry and antibody appearance. Antibodies produced are mainly of the IgG type.
Antigen-Antibody Reaction:
When antibodies recognize antigens, they bind via various forces (e.g., van der Waals forces, hydrophobic, ionic). This can lead to reactions like precipitation or agglutination.
Primary Barrier:
Includes the thickness of the skin, the process of keratinization and shedding of external cellular layers, secretions from sebaceous glands and sweat, and the skin’s bacterial flora.
Phagocytic Defense:
Involves phagocytic leukocytes in the blood, such as neutrophils and monocytes.
T Lymphocytes:
Originate in the thymus. They are involved in cellular immunity and do not produce antibodies. They are relatively resistant to inactivation by X-rays.
B Lymphocytes:
Originate in bone marrow (in mammals; Bursa of Fabricius in birds). They produce antibodies and are involved in humoral immunity.
Cytotoxic T Lymphocytes:
Destroy cells infected by viruses or intracellular bacterial pathogens by releasing cytotoxins like perforin, which creates pores in the infected cell’s plasma membrane, leading to cell destruction.
Helper T Lymphocytes:
Responsible for activating B lymphocytes and initiating the proliferation of cytotoxic T lymphocytes through the secretion of interleukins.
NK Cells (Natural Killer Cells):
Found in the blood of vertebrates. They destroy some types of cancer cells and virus-infected cells. Their action is similar to cytotoxic T cells but is not antigen-specific.
Antibodies:
Protein molecules produced by B lymphocytes that bind to specific antigens.
Complement System:
A system of plasma proteins that supports and augments mechanisms of the immune response.
Interferons:
Small plasma proteins produced by T lymphocytes and NK cells. They primarily interfere with virus replication within cells.