I&I Introduction to Immune Responses Flashcards
What are physical barriers to infection and how do organisms overcome this?
-Skin provides a protective cover
-Organisms can overcome this barrier
-Cuts or damaged skin
-Insect bites
-Animal bites
What are mucus linings and what do they do?
-There are areas of the body that are not covered by skin
-Mucus traps organisms
What does bacteria in genital tract always cause?
-Commensal organisms present in genital tract which always causes competition
What can happen if antibiotics used for treatment kill commensal organism that usuallt reside in genital tract?
-If antibiotics used for treatment result in the death of bacteria that normally resides in genital tract, this can cause less competition and increase likelihood to get infection
What is the innate immune system also known as anad what is it?
-Also known as non-specific immunity and is the first line of defence in the immune response
What is the main cell which makes up innate immune system and what does it include?
-Includes Phagocytes(effector cells):
-neutrophils
-Macrophages
-dendritic cells
What is the origin of phagocytes?
-Origin of phagocytes is generated in the bone marrow
What are other type of cells involved in innate immune system?
-Also include:
-Mast cells
-Eosinophils
-Basophils
-Natural killer cells
What do macrophages start as and where are they activated?
-They start as monocytes then they are activated in the tissue and become macrophages
How do macrophages work?
-Microbe must attach to phagocyte
-Ingestion initiated
-Organism enters the phagocyte in a vacuole
-Destroyed within this vacuole
What do dendritic cells enter?
-They enter skin, mucosa, tissues
How do dendritic cells work?
-How it works
-Capture microbes
-Phagocytosis
-eliminate the microbe
- they also present the microbes as antigens to T cells
What do phagocytes present microbe as and to what?
-Phagocytes present the microbe as antigens to T cells
What protein do phagocytes work with in order to destroy an organism
-Complement and phagocytes work together in destroying an organism
What is complement?
-Complement are a group of proteins that assist with the attachment of micro-organisms and phagocytes
What does complement act as?
-Complement also act as an enzyme cascade system
What does complement enhance?
-Complement enhance phagocytic function
What do phagocytes aslo produce?
-Phagocytes also produce substances that attract other cells to the site
-Chemotactic substances
What permeability does do phagocytes increase?
Phagocytes also increase vascular permeability to allow immune cells to get in
What does inflammation attract and help with?
-Attract cells to site
-Help killing and clearance of organisms
What do interferons intefere with?
-Interferons interfere with viruses infecting other cells
What do natural killer cells play a role of and how so?
-Play a role of surveillance
-Any cell that has changed is a target for killing
What are other examples of innate immune system defences
-Inflammation (CRP, Acute phase proteins APP)
-Interferons
-Natural killer cells
What type of response is the adaptive immune system and what does it include?
-Highly specific immune response
-Includes B and T lymphocytes
How do B lymphocytes recognise an antigen?
-B lymphocytes recognise antigen through immunoglobulin receptors on their surface
How do T lymphocytes recognise an antigen?
-T lymphocytes recognise antigen through T cell receptors
What happens when lymphocytes bind to antigens?
-When their receptor bind to an antigen, they proliferate and form clones
What is the response of memory lymphocytes in response to an antigen and what are 2 characteristics of memory lymphocytes?
Memory lymphocytes will return to patrol
-They are non-dividing and long lived
What do effector cells remove?
-Effector cells
-These remove the virally infected cells lysed by T-lymphocytes
-Bacteria covered by antibodies
What do B cells make?
B cells make antibodies
What are antibodies and which one is made before the other?
-Antibodies are immunoglobulins
-IgM is made first and then IgG
What is a characteristic of B cells and what happens when they’re acativated?
-B cells are very specific and when activated, they cause proliferation of clone and make correct antibodies
What are 2 ways antibodies work?
- Work by neutralsation
- Opsonization
How does neutralisation by antibodies occur?
-E.g. they coat virus with antibody and stop it from entering cells
How does opsonization by antibodies occur?
-Opsonin’s tag foreign pathogens for elimination by phagocytes
What do T helper cells aid with and how is this done?
-T helper cells aid B cells make antibodies once they are activated
-This is by releasing cytokines that promote B cells to produce antibodies
How are T helper cells activated?
-Phagocytes present antigen of the infectious agent to T helper cells in order to activate them
What are T cytotoxic cells?
Cells that kill
How do T-cytotoxic cells work?
-They work by attaching to MHC and virus protein on surface of infected cell
-Viruses produce protein which are attached to a cell protein called major histocompatibility complex(MHC) and appears on the cell surface
