Immunology + Innate immunity Flashcards
What is immunity?
Protect against foreign pathogens (invaders/dangers) or substances (antigens)
Microbes are pathogenic when:
They manage to penetrate the immune defense
What is dysbiosis and what does it lead to?
Imbalance in bacteria, leading to immune overstimulation resulting in inflammation
how does our body recognize pathogens?
the cells of the immune system recognize molecules that are different than its own molecules
what are the two types of immunity?
innate and adaptive
what is innate immunity?
non-specific, quick reaction, universal, aways ready
what are some barriers associated with the innate immune system?
skin, mucus membranes, cough, sweat, stomach acid, enzymes, toxic molecules
what are the cellular components of innate immunity?
epithelial cells, phagocytes, natural killer cells
what are the cells of adaptive immunity?
T and B lymphocytes
what caused us to have active immunity?
result from recombination activating gene (RAG) that allows genes for somatic recombination encoding B/T cell receptors (allowing specificity for different pathogens)
Adaptive immunity protects us how?
allows protection after infection, learns through experience, antigen specific, memory
what is humoral immunity?
involves combating pathogens with antibodies
What are alternate names for antibodies?
gamma globulins or immunoglobulins
what is passive immunity?
antibodies can be transferred between individuals to provide protection (ex mother antibodies through placenta)
what is active immunity?
natura infection or vaccination engage the immune defense to make their own antibodies
long lived protection through immune system’s memory
what is cell mediated immunity?
involves work of T cells eradicating the infectious agents and aid other cells
transferring of white blood cells _____
confers immunity
how do immune cells arise?
from hematopoietic stem cells and progenitor cells
what is hematopoiesis?
process that allows HSC to differentiate into many different types of blood cells
where does hematopoiesis occur?
bone marrow
in the bone marrow the HSC cells differentiate into two major cell types, what are they?
common myeloid and lymphoid progenitor cells
what are some examples of myeloid progenitor cells?
RBC, megakaryocytes, monocytes/macrophages (and dendritic cells), granulocytes
what do dendritic cells do?
-capture microbial and other antigens and display them to lymphocytes
-present antigen to T cells and provide signals that stimulate the proliferation and differentiation of lymphocytes
what does a neutrophil do?
direct harm to pathogens, prominent at wounds, phagocytic, produce digestive enzymes and free radicals
also vasodilation + inflammation
what does a eosinophil do?
antiviral + anti-parasite
induces ROS, vasodilation, basophil degranulation, chemokines
what is the difference between a basophil and a mast cell? what do they do?
Basophil- in blood
mast cell- in tissues
inflammation and allergies
histamine, heparin, leukotrienes
what does heparin do?
increase blood flow
what does leukotrienes do?
regulate inflammation
what do monocytes/macrophages do?
phagocytosis
contain digestive enzymes, antimicrobia peptides, produce free radicals (to kill pathogens), vessel diaating substances
How do macrophages help with tissue repair?
resolve inflammation by producing anti- inflammatory signals and signal tissue healing cells to arrive
B cells are
humoral
T cells are
cell mediated
what do cytotoxic T lymphocytes (Tc or CTL) do?
lyse infected cells
what do T helper and T regulatory cells do?
guide behavior of other cells (like CTL or B cell)
B lymphocytes express:
B cell receptors that bind antigens (present antigen in secondary response)
what are some key features of B lymphocytes?
produce antibodies, differentiate into plasma cells, humoral immunity, memory
what do cytotoxic T cells do?
extracellular killng
what do T helper cells do?
UP regulation of immune response
what do T regulatory cells do?
down reg of immune response
What do natural killer T cells do?
share properties with B, T and NK cells
bind foreign lipids, self lipids and glycolipids
activate NK cells
produces large quantity of cytokines
what do natural killer cells do?
destroy cells that do not present MHC I
tumor surveillance
what are clusters of differentiation?
surface molecules that differentiate lymphocytes (often the only way to differentiate them)
B lymphocytes develop in contact
with the ______ of the _______
stromal cells of the bone marrow
T lymphocytes develop in contact
with the ______ of the ________
stromal cells of the Thymus
what are secondary lymphoid organs?
Areas where lymphocytes encounter antigens, become activated, undergo clonal expansion, and differentiate into effector cells (Lymph nodes, Spleen, Mucosa-associated lymphoid tissues (MALT))
At the site of infection -
Endothelium expresses intercellular adhesion molecules (ICAM) and produces:
chemokines
what is margination?
Immune cells adhere to endothelial cells by their adhesion molecules (integrins) which bind to ICAM
what is extravasation?
Using ICAM molecules for traction, the leukocyte pushes its
way between the cells of the endothelium and enters the surrounding tissue
what is the hallmark of adaptive immunity
memory
When a foreign antigen enters the body through a splinter into his sole, which of the following portions of the lymphoid system is the antigen MOST likely to reach FIRST?
(a) Spleen
(b) Liver
(c) Thymus
(d) Regional lymph nodes
(e) Mucosal-associated lymphoid tissue (MALT)
(d) Regional lymph nodes
What two distinct strategies are used for innate immunity?
-microbial non-self
-missing self (no MHC)
what are some microbial non-self molecules?
-PAMPS
invariant
products of metabolic pathways
unique molecules produced by microbes
what are examples of PAMPs?
Lipopolysaccharide of gram-negative bacteria
Double-strand RNA produced by most viruses
what are Endogenous danger molecules (DAMPs)?
Damaged or dying cells release endogenous danger molecules and activate the innate immune system
what receptor is used for PAMPs?
pattern recognition receptors
(variations are intracellular, surface and secreted)
The binding of PAMPS to PRR triggers _______, Leading to _____
immune responses
Leads to the production of molecules that control adaptive
immunity (PAMPs: PRR links innate to adaptive immunity)
How do NK cells recognize targets?
activation signaling
-immunoreceptor tyrosine-
based activation motifs
(ITAMS)
– Phosphorylation of protein
tyrosine kinase
What occurs in normal cells that express MHC?
no activation, inhibitory receptors bind to the MHC I resulting phosphorylation (undoes that the activation signaling would do?
what are ways to identity the inflammatory response is on?
erythrocyte sedimentation test
& C reactive protein (macrophages make liver make it)
what is a conventional dendritic cell?
– response to activation by microbes’ PAMPs
– display microbial antigens to T lymphocytes
What is the first layer of defense for the
innate immune system?
A. Epithelial layers
B. Innate lymphoid cells
C. NK cells
D. Neutrophils
E. Macrophages
A. Epithelial layers
After a skin infection, which immune cells play the key role in tissue healing?
A. Cytotoxic T cells
B. Eosinophils
C. Macrophages
D. Mast cells
E. B lymphocytes
C. Macrophages
