Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Antigens are foreign substances that stimulate an immune response. They are often proteins or very large polysaccharides found on the surface of pathogens, such as the glycoproteins that determine the blood groups.
The immune response involves a process of challenge and response. Antigens are ingested by macrophages and presented to helper cells ( cells).
Activated cells bind to specific lymphocytes that have the corresponding surface antibody. This interaction, mediated by cytokines, triggers clonal selection.
Clonal expansion occurs when the activated cell undergoes mitosis to produce a large population of plasma cells and memory cells.
Plasma cells are specialized for the synthesis and secretion of antibodies (). These molecules are -shaped and consist of two heavy and two light polypeptide chains.
Memory cells provide long-term immunity. If the same pathogen enters the body again, memory cells rapidly divide into plasma cells, producing a faster and greater quantity of antibodies ( ).
Vaccination involves introducing a weakened or killed form of a pathogen (or its antigens) to stimulate the production of memory cells without causing the disease.
Monoclonal antibodies are highly specific, purified antibodies produced by a cell (a fusion of a lymphocyte and a myeloma/cancer cell).
Allergies result from an overactive immune response where antibodies bind to mast cells, causing the release of when an allergen is encountered.
Zoonosis is the transmission of pathogens from animals to humans, such as the virus or .
📐Formulae
💡Examples
Problem 1:
Calculate the probability of a transfusion reaction if an individual with blood type receives a transfusion of blood type .
Solution:
(Agglutination will occur).
Explanation:
Individuals with blood type have both anti- and anti- antibodies in their plasma. Since type blood cells express both and antigens, the recipient's antibodies will attack the donor cells, leading to agglutination and potential .
Problem 2:
Explain the role of monoclonal antibodies in a pregnancy test strip.
Solution:
The test uses antibodies specific to the hormone (human chorionic gonadotropin).
Explanation:
The strip contains mobile monoclonal antibodies conjugated to a dye (-linked). If is present in the urine, it binds to these antibodies. As the liquid moves up the strip, the -antibody complex binds to fixed antibodies in the 'test' zone, concentrating the dye and producing a visible line.