Microbio Immunology Flashcards
What 4 things must a pathogen to in order to cause disease?
- gain access to the body
- attach to and/or enter cells of its host
- reproduce and avoid host’s immune system
- induce harmful changes in the host
immunity definition
the ability of the body to ward off disease through defense mechanisms.
ability to protect and prevent against microbes and their products, environmental agents (allergens and toxins) and malignant tumor formation
susceptibility definition
body’s vulnerability to diseases
Why understand immunology?
to diagnostic, treat, manage and prevent diseases
to research to optimize immune responses
what is the immune system?
a network of cells, tissues, and organs that work together to protect the body from infection and other harmful substances
What are the three type of responses?
innate immune response
adaptive immune response
immune memory
Innate immune response
Defense mechanisms, present at birth
always present and available
occurs immediately, cells are always circulating
non-specific
Adaptive immune response
specific response to specific pathogens once they have breached innate immunity
Immune memory
follows adaptive response
highly specific to the original pathogen
retained for later use
Innate response vs adaptive response
Innate= prevent entry and invasion adaptive= remember the previous assault and protect when encountered again
how does the immune system prevent diseases?
prevent entry of pathogens
neutralize and remove pathogens after they have entered the body
destroy body’s cells that have changed due to an illness
What are the cellular components of the immune system? (3 cells)
bone marrow
myeloid cells
lymphoid cells
bone marrow
contains stem cells, precursors for all immune cells
what are the 6 myeloid cells?
eosinophils, basophils, mast cells, monocytes, dendritic cells, macrophages
what are the three lymphoid cells?
B cells, T cells, natural killer cells
What is the organ of the immune system?
thymus gland
What is the lymphatic system?
network of vessels and tissues composed of lymph (extracellular fluid) and lymphoid organs (lymph nodes)
primary lymphoid organs (2)
thymus
bone marrow
secondary lymphoid organs (3)
lymph node
spleen
mucosa associated lymphoid tissue
Immune response- first line of defense
innate and nonspecific
physical barriers, chemical barriers
skin and mucous membranes
normal microbiota
Immune response- second line of defense
innate and nonspecific phagocytes inflammation fever antimicrobial substances
what cells are phagocytes? (4)
neutrophils
eosinophils
monocytes/macrophages
What is a main characteristic of Leukocytes and there are they found?
What are the 5 types of cells in this category?
presence of granules in the cytoplasm
Basophils, eosinophils, neutrophils, lymphocytes, monocytes
Which cells are involved in the innate immune system? (6)
Neutrophils, eosinophils, basophils
monocytes/ dendritic cells/macrophages
characteristics of cells in the innate immune system (4)
ability to respond quickly and broadly, usually leads to inflammation
activates adaptive immunity
host defense
disorders in innate cell function may cause chronic susceptibility to infection
origin and development of all immune cells
come from precursors in the bone marrow
develop into mature cells in different parts of the body
What four cells are granulocytes
Neutrophils, Eosinophils, basophils, mast cells
Neutrophils
most abundant WBC, pus. respond quickly following tissue injury. hallmark of acute inflammation. phagocyte
eosinophils
main effecter cells in allergic responses and asthma. fights parasitic.helminth colonization. phagocyte
Basophils
least common, releases histamine and other inflammatory chemicals
mast cells
key role in inflammation allergy and anaphylaxix
what two cells are agranulocytes
lymphocytes
monocytes
lymphocytes
most involved in specific immunity T-cells, B-cells, natural killer cells
Monocytes
circulate in the blood, leave blood and mature into macrophages in tissues
5 examples of agranulocytes and their location in the body
Tissue= histiocytes Liver= kupffer cell Skin= langerhan's cells and dendritic cells Brain= microglia Bone= osteoclast
what are the five stages of phagocytosis
chemotaxis adherence ingestion digestion elimination
oposonization
process by which a microbe is marked for destruction by phagocytes
Phagocytosis step 1- chemotaxis
chemical attraction of phagocytes to microorganisms
phagocytosis step 2- adherence
attachment of phagocytic membrane to microorganisms or foreign material
phagocyte receptors= troll like receptors (TLRs) and PAMP or DAMP molecules
Phagocytosis step 3- ingestion
pseudopods engulf the organism and form a phagosome or phagocytic vehicle
phagocytosis step 4- digestion
cytoplasm of phagosome fuses with a lysosome- phagolysosome
phagocytosis step 5- elimination
residual body exits the cell. exocytosis
Inflammation cause
second line of defense
canbe cuased by microbes, physical and chemical agents
host response to tissue damage
inflammation purpose
to destroy the infectious agent, to confine it and repair or replace the damaged tissue
inflammation signs
redness, pain, heat, swelling, loss of function
fever
hypothalamus control body temp. products of microbes induce the release of cytokines
complement
innate immune system. 30+ protein are activated as a cascade by pathogen or antigen/antibody reaction
complement= action of proteins to destroy microbes. What are the three actions?
- enhance phagocytosis
- inflammation
- cytolysis (MAC)
three complement pathways
- classic
- alternate
- lectin
Membrane attack complex
c5-c9 undergoes polymerizaion.
punch a hole in pathogen’s membrane= cause cell to leak and die
Interferon
a group of signaling proteins (cytokines) released by host cells in response to infeciton with pathogens like bacteria and viral particles
Three types of interferons
alpha, beta, gamma
iron binding proteins
bind iron tightly to make iron unavailable for microbial use, limiting growth
4 iron binding proteins
transferrin, lactoferrin, ferritin, hemoglobin
adaptive immunity
third line of defense, specific. induced against a specific pathogen or molecule
Two types of adaptive immunity response
humoral- antibody mediated (B-cells) cell mediated (T-cells)
anamestic response
secondary reaction in adaptive immunity. a quicked and more intense response on subsequent exposure to the pathogen
antigen
a substance or molecule that causes an immune system to produce antibodies against it.
proteins or large polysaccharides, lipids or nucleic acids.
microbial or non-microbial
epitopes
antigenic determinants.
a specific region of an antigen which interacts with an antibody
hapten
low MW compounds which can’t induce an antibody response by itself. attaches to a carrier molecule to induce antibody response
example of hapten
penicillin allergy
antibody
proteins called immunoglobulins. produced during a humoral immune response by a B-cell (plasma cell)
valence
number of antigen bonding sites in an antibody
Types of immunoglobulins
IgG= monomer, 60% of total serum antibody, can transfer placenta. IgM= pentamer, first antibody produced. IgA= dimer, located in secretions. IgD= monomer, located in B-cells IgE= allergic reactions
Two categories of adaptive immunity
Naturally or artificially acquired
Naturally acquired active immunity
antigens enter body naturally, body induces antibodies and specialized lymphocytes
Naturally acquired passive immunity
antibodies pass from mother to placenta
Artificially acquired active immunity
antigens are introduces in vaccines, body produces antibodies and specialized lymphocytes
Artificially acquired passive immunity
preformed antibodies in immune system are introduced by injection
Major Histocompatibility complex (MHC)
cell surface molecules that play a major role in cell-mediated immune repsonses. bind to foreign antigens and present them to T-cells
Characteristics of MHC (3)
Polygenic= multiple genes are involved. Codominant= expression is from both sets of inherited alleles. polyphorphic= multiple variants of each
classes of MHC (2)
class 1= present in all nucleated cells (CD8) Class 2= present only on antigen presenting cells (CD4)
T-lymphocytes types (2)
- T-helper cells= CD4
2. T-cytotoxic cells= CD8
CD4 and 8
CD= cluster differentiation
membrane-associated glycoproteins that serve as a co-receptor for the T cell receptor
Antigen presenting cells (APCs)
process and present antigens for recognition to T-cells
what are the four APCs?
macrophages, B-cells, dendritic cells, langerhans cells
Cytotoxic T cells
releases perforins and a proteolytic enzyme (granzymes) that kill the target cell
Antibody Dependent Cell mediated Cytotoxicity (ADCC)
killing of an antibody-coated target cell by a cytotoxic effector cell through a non-phagocytic process. release of content of cytotoxic granules
cytokines
chemical messengers produced during immune response by the cells of immune system.
small cytokines involved in chemotaxis
