5: Cell Recognition and The Immune System Flashcards
Pathogen
Any microorganism that causes disease
Immunity
The means by which the body protects itself from infection
Phagocyte
White blood cells that engulf microorganisms
Phagosome
The vessel that forms when the phagocyte engulfs a pathogen.
Lysozymes
Hydrolytic enzymes that destroy ingested bacteria by hydrolysis of their cell wall.
Antigen
Any part of an organism that is recognised as foreign and stimulates an immune response
B-lymphocytes
White blood cells that are associated with humoral immunity
T-lymphocytes
White blood cells that are associated with cell-mediated immunity
Antigen-presenting cells
Cells that display foreign antigens in their surface
Cell-mediated immunity
When T-lymphocytes respond to antigens that are presented on a body cell
Cytotoxic T-cells
They kill abnormal cells and body cells that are infected by pathogens, by producing perforin that produces holes in the cell-surface membrane
Humoral Immunity
Immunity that involves antibodies
Clonal selection
When T-helper cells stimulate B cells to divide by mitosis to form clone identical B cells
Plasma cells
Cells that secrete specific antibodies that lead to the destruction of specific pathogen
Memory cells
Cloned B cells that circulate within the blood, ready for any future infection from the same pathogen
Antibodies
Proteins with specific binding sites synthesised by B cells
Antigen-antibody complex
This forms because each antibody has a specific binding site that fits precisely onto the specific antigen
Variable region
The binding site of an antibody which is different for different antibodies
Constant region
The part of the antibody that is not variable
Monoclonal antibodies
A single type of antibody which is isolated and cloned outside of the body
Antibiotic
A substance produced by living organisms that can destroy or inhibit the growth of bacteria
Antibiotic resistance
The development in microorganism of mechanisms that prevent antibiotics from killing them
Herd immunity
When a sufficiently large proportion of the population has been vaccinated to make it difficult for the pathogen to spread within the population
Antigenic variability
When a pathogen mutates frequently, so that vaccines suddenly become ineffective
Vaccination
The introduction of a vaccine containing appropriate disease antigens into the body
Retroviruses
The group of viruses that HIV belongs to
ELIZA test (Enzyme Linked ImmunoSorbant Assay)
A test used to detect HIV and other diseases, allergens and drugs
