Immune response Flashcards
(51 cards)
What makes the specific response possible?
The presence of what?
Antigens on the surface of the pathogen
What are antigens?
Made of proteins or glycoproteins
Found on the surface of cells to identify themselves as self or non self
Name 4 processes involved in the non-specific response
Phagocytosis
Lysosyme action
Interferons
Inflammation
Inflammation can be characterized by?
Swelling
Painful to touch
Localised increase in temperature
Redness
What cells produce histamine?
Mast cells
What do mast cells produce?
Histamine
What is the main function of histamine?
It is a cell signaling molecule, therefore performs cell signaling
What does histamine stimulate?
Vasodilation to increase blood flow through capillaries
Increases permeability of capillary walls causing fluids to enter the tissue (causing swelling)
Phagocytes leave the blood and enter the tissue to engulf foreign particles
Cytokines are released, another cell signaling molecule, triggering an immune response in the infected area
What are interferons?
They are anti-viral proteins produced by infected cells
What do interferons do?
Inhibit the production of viral proteins
Activate WBCs involved in the specific response to destroy infected cells
Describe the phagocytes’ mode of action
Chemicals from pathogens and from cells under attack (histamine) attract the phagocyte to the site of the pathogen
The phagocyte recognizes the non-self antigens on the pathogen
Phagocytosis occurs
Digestive enzymes are released onto the pathogen once lysosomes fuse with the phagocytic vacuole (endocytosis)
Post digestion the phagocyte presents the antigens of the pathogen on its surface and turns into an Antigen Presenting Cell (APC)
This presentation triggers the specific immune response
Which cells produce antibodies?
Plasma cells
What do plasma cells produce?
Antibodies
What do plasma cells produce?
Antibodies
Describe the structure of immunoglobins
Y-shaped molecule consisting of 2 heavy and 2 light polypeptide chains connected by a disulfide bond
Each polypeptide chain has a constant region and a variable region
AA sequence in variable region differs from antibody to antibody
Antigen binding site exists at the end of the variable region
AA sequence in this site is varying greatly hence giving antibodies their specificity
What is an epitope of an antigen?
Region of the antigen that binds to the antibody
What are the ways in which antibodies can function?
Inhibition – They bind to the receptors on body cells to prevent pathogens from entering them by binding to them
Agglutination – Cause the pathogens to clump together, this reduces the chances of the pathogen spreading and makes it easier for the phagocytes to destroy them
Neutralization – They can act as anti-toxins and destroy the pathogens
Name 2 types of lymphocytes involved in the specific response
T cell – killer, memory, helper
B cell – memory, effector
Where are T cells made?
In the bone marrow. They finish maturing in the thymus
Describe T cells
They have specific receptors on their cell surface membrane known as T cell receptors which are specific to antigens and can bind with them
How to T cells operate post activation?
Activation of T cells occur once their receptors bind to specific antigens. These antigens may come from APCS (macrophages), infected cells or the pathogen itself
The T cells then rapidly multiply to form clones of itself by mitosis
What are the 3 types of T cells?
Helper
Memory
Killer
Give the functions of T helper cells
Release of cell signaling chemicals that stimulate B cells and active T killer cells
Opsonisation – Release of opsonins which label pathogens so that they can be subjected to phagocytosis
What is the function of T killer cells?
Bind to and destroy infected cells
How do T killer cells operate?
By creating holes in the surface of the cell causing it to lyse
