Immunology Flashcards
What is phagocytosis?
The process by which phagocytes engulf and digest foreign particles or disease-causing organisms.
name 2 types of phagocytic white blood cells
neutrophils
macrophages/monocytes
what role do phagocytes play as antigen-presenting cells?
They break up foreign particles into components, display these on their membrane, and activate T helper cells.
which cells produce histamine and what is its function?
Basophils and mast cells produce histamine, which increases capillary permeability to facilitate immune responses.
what are the 3 ways mast cells can be activated?
Direct injury
binding to IgE antibodies
activated complement proteins.
where do B lymphocytes mature?
B lymphocytes mature in the bone marrow and produce antibodies in response to antigens.
how do T lymphocytes differ from B lymphocytes in antigen recognition?
T cells recognize antigens bound to MHC proteins, while B cells directly bind to antigens.
describe the role of T helper cells
They activate other immune cells such as macrophages, B cells, and cytotoxic T cells to respond to antigens.
what is the function of T cytotoxic cells?
To eliminate virus-infected cells, tumor cells, and foreign grafts.
what is the difference between humoral and cell mediated immunity?
Humoral immunity involves B cells and antibodies against extracellular pathogens, while cell-mediated immunity involves T cells and targets intracellular pathogens.
what are antibodies and what is their structure?
Antibodies are Y-shaped glycoproteins made of four polypeptide chains (two heavy and two light), held together by disulfide and non-covalent bonds.
list the 5 types of antibodies
IgM
IgE
IgG
IgA
IgD
what is the main role of IgG antibodies?
They detoxify harmful substances and are transferred across the placenta to protect the fetus.
how are monoclonal antibodies produced?
Through the hybridoma method, combining specific B cells with myeloma cells to produce identical antibodies.
what are monoclonal antibodies used for in pregnancy testing kits?
They detect the hormone HCG, produced by the early embryo.
what is chemotaxis in the context of phagocytosis?
The movement of phagocytes towards the site of infection in response to chemical signals from pathogens.
what are the 4 main steps in phagocytosis?
Activation and chemotaxis, recognition of microbes, ingestion, and destruction of the pathogen.
what function do pseudopods serve during phagocytosis?
They are extensions of the phagocyte’s cytoplasm that surround and engulf foreign particles, forming a vacuole.
what is the role of the complement proteins in phagocytosis?
They help attract microorganisms to the phagocyte’s membrane to facilitate engulfment.
how do mast cells contribute to allergic reactions?
They release histamine and other chemicals, causing blood vessel expansion, itching, and mucus buildup.
what are memory B cells and why are they important?
Memory B cells are long-lived cells that remain in the bloodstream, enabling a rapid immune response if the same antigen is encountered again.
what distinguishes T memory cells from other T lymphocytes?
T memory cells have a longer lifespan and can rapidly respond to previously encountered antigens.
What is the Major Histocompatibility Complex (MHC), and why is it significant?
MHC is a set of proteins on cell membranes that present antigens to T cells, crucial for immune recognition.
How does IgA contribute to he body’s defense?
It is found in mucosal areas, such as saliva and breast milk, providing the first line of defense against pathogens.
what is the primary role of IgE antibodies?
They are involved in allergic responses and protect against parasitic infections.
Explain the difference between IgM and IgD antibodies
IgM is the first antibody produced during an immune response and is involved in agglutination, while IgD is involved in the activation of B cells.
what triggers the production of antibodies by B lymphocytes?
The binding of a specific antigen to the membrane-bound immunoglobulin (B cell receptor) on the B lymphocyte.
what hapens during the differentiation of B cells into plasma cells?
The B cells lose their surface antibody and begin producing large amounts of specific antibodies to fight infections.
what is the role of cytokines in cell-mediated immunity?
They are signaling molecules that help regulate immune responses by activating T cells, macrophages, and other immune cells.
why is humoral immunity considered faster than cell mediated immunity?
Humoral immunity involves the rapid production of antibodies against extracellular pathogens, while cell-mediated immunity targets intracellular pathogens, requiring more complex cellular interactions
what are the roles of neutrophils in the immune response?
Neutrophils are a type of phagocyte that make up about 60% of white blood cells.
They are one of the first responders to infection and help by engulfing and destroying pathogens.
how do macrophages differ from neutrophils in their immune function?
While both are phagocytes, macrophages are larger, live longer, and are present in higher numbers in tissues like the liver. They also act as antigen-presenting cells, playing a crucial role in activating adaptive immunity.
what is agglutination and how do antibodies contribute to this process?
Agglutination is the clumping together of pathogens. Antibodies, especially IgM, bind to antigens on the surface of pathogens, making them easier targets for phagocytes.
why are monoclonal antibodies highly specific to their target antigens?
They are produced by identical immune cells cloned from a single parent cell, ensuring that all the antibodies recognize the same specific antigen.
what is the significance of CD4 and CD8 proteins in T cells?
CD4 proteins are found on T helper cells and help recognize antigens presented by MHC class II molecules. CD8 proteins are on T cytotoxic cells and recognize antigens presented by MHC class I molecules.
how does the complement system enhance the immune response?
The complement system consists of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens, promote inflammation, and attack the pathogen’s cell membrane.
explain the concept of clonal selection in adaptive immunity
When a B or T cell encounters its specific antigen, it is activated to proliferate and form a clone of cells specific to that antigen. This process is essential for the adaptive immune response.
what roles do memory cells play in vaccination?
Vaccination induces the formation of memory cells that remain in the body and provide long-term protection by mounting a rapid response if the pathogen is encountered again.
how do plasma cells differ from memory B cells?
Plasma cells are differentiated B cells that produce and secrete large quantities of antibodies during an active infection, while memory B cells remain in the bloodstream to provide immunity for future exposures.
describe how allergic reactions are triggered in the immune system
Allergic reactions occur when mast cells, activated by IgE antibodies bound to allergens, release histamine and other mediators that cause symptoms such as swelling, itching, and mucus production.
what is the role of antigen presenting cells in the immune system?
APCs, such as macrophages, dendritic cells, and B cells, process and display antigens on their surface to activate T cells, linking the innate and adaptive immune responses.
how does humoral immunity protect against extracellular pathogens?
Humoral immunity involves the production of antibodies that circulate in the blood and lymph, neutralizing pathogens and marking them for destruction by other immune cells.
what are the potential herapeutic uses of monoclonal antibodies?
Monoclonal antibodies can be used in cancer treatment, autoimmune disease management, and infectious disease therapy by specifically targeting diseased cells or harmful pathogens.
why is the variable region of an antibody important?
The variable region allows antibodies to bind specifically to different antigens, providing the immune system with the ability to recognize a vast array of pathogens.
what are cytokines and what role do they play in immunity?
Cytokines are signaling proteins released by immune cells that facilitate communication and coordination during immune responses, such as inflammation and activation of lymphocytes.
what is the role of the thymus in the immune system?
The thymus is where T lymphocytes mature and differentiate, which is crucial for developing a functional adaptive immune response.
how do antibodies neutralize toxins?
Antibodies can bind to toxins produced by pathogens, preventing them from interacting with host cells and neutralizing their harmful effects.
what distinguishes natural immunity from artificial immunity?
Natural immunity is acquired through natural exposure to pathogens, while artificial immunity is obtained through medical interventions, such as vaccines or antibody injections.
