Immunity Flashcards
What are the main defence mechanisms of the body?
Skin, an impermeable barrier made of keratin
Cilia and Mucus in lungs
Stomach acid
Wax
What is cell-mediated immunity?
Phagoctyosed, presents antigen on surface
APC
Th with specific receptors bind to unique antigen
Clonal selection
Differentiation into:
Helper cells
Killer cells
Memory cells
What are specific responses?
Cell-mediated and Humoral response
What are non-specific responses?
Phagocytosis
How does the body distinguish between its own cells and foreign material?
Each type of cell has specific molecules on its surface that identify it such as surface chemicals and attachment proteins.
explain the process of phagocytosis:
pathogen releases chemicals
this attracts the phagocyte
the phagocyte binds to the pathogen
the phagocyte engulfs the pathogen
forms a phagosome around the pathogen
lysosomes inside the phagocyte release digestive enzymes into the phagosome
breaking down the pathogen by hydrolysis
What are the 2 different types of lymphocytes?
T and B
T produced in bone marrow and mature in thymus
Can you describe the response of T lymphocytes to a foreign antigen?
Bind to complementary specific antigen activate T-lymph and divide by mitosis (clonal selection)
What is the role of antigen-presenting cells in the cellular response?
Activate specific t helper Cell
What is humoral immunity?
Surface antigens taken up by B cells
APC
Th cells attach to process antigens and activate B cell
Clonal selection
Differentiate into
B plasa
B memory
Can you describe the role of helper T cells (TH cells)? in Humoral immunity
Bind with B cell to aid activation of B cell
How do cytotoxic T cells kill infected cells?
Perforins make holes in plasma membrane, making it freely permeable.
What are plasma cells? What type of immune response do they produce?
Produce Ab that attach to antigens and disable/agglutinate
Primary response.
What are memory cells? What type of immune response do they produce?
Circulate in the blood ready to response to future infection.
Secondary Response.
Can you describe the response of B lymphocytes to a foreign antigen?
Antigen binds to antibodies on B cell, Th cell binds to bonded antigen and activated B cell, clonal selection, mitosis.
What are monoclonal antibodies? How are they produced?
Proteins with specific binding sites produced by B-cells
Complementary to specific antigen
Specific protein binds to one antigen type.
Made from a hybdridoma of B cells and melanoma
Monoclonal antibodies produced are identical and complementary to the same antigen.
What is passive immunity?
Antibodies received from else where eg mother or antiserum
Immediate short term protection
Can you explain the formation of an antigen-antibody complex?
Bind to specific antigen
Clump them together
Too large to enter host cell
Agglutination
How can monoclonal antibodies be used to target specific cell types?
Monoclonal antibodies have a specifically shaped variable region only complementary to a specific antigen.
What are the differences between active and passive immunity?
Active: long term slow memory cells
Passive: short term quick and no memory cells
Can you describe the ethical issues associated with the use of monoclonal antibodies?
Animal cruelty involves genetic engineering of mice to produce human antibodies.
Testing antibodies on humans, unexpected side effects.
How can monoclonal antibodies be used in medical diagnosis?
Showing presence of a particular antigen eg covid test.
Sample and mobile antibodies form complex
Bind to immobilised antibodies with fluorescent marker
Excess antibodies from sample start bind to immobilised control Ab with marker.
What is active immunity?
Provided by B-memory after primary response.
What is a vaccination?
A weak or attenuated form of a pathogen to elicit a controlled immune response.
