EXAM 1 Intro to Immunology and Generalized Responses to Infection Flashcards
what are the 5 roles of the immune system?
- kill or control pathogens
- control disease
- repair tissue damage
- organ development
- maintain organ integrity and function
pathogens damage tissues in what two major ways?
directly and indirectly
what are the 3 ways that pathogens directly damage tissues?
- exotoxin production
- endotoxin
- direct cytopathic effect
what are the 3 ways that pathogens indirectly damage tissues?
- immune complexes
- anti-host antibody
- cell-mediated immunity
what is an exotoxin?
a pathogen-secreted toxin
what is an endotoxin?
a toxic pathogen component
describe the form diversity challenge that pathogens present to the immune system
there are roughly 1400 diverse forms of pathogens
describe the life cycle diversity challenge that pathogens present to the immune system
- pathogens often infect multiple body compartments
- pathogen physiology changes with life cycle
- no single immune response type clears a pathogen
- ex. listeria monocytogenes infection
describe the diverse routes of infection challenge that pathogens present to the immune system
- mouth and respiratory tract
- GI tract
- reproductive tract
- opportunistic pathogens - resident micriobiota
- external surface
- wounds and abrasions
- insect bites
describe the challenge of rapid, targeted response over a broad domain that pathogens present to the immune system
- immune system has to respond to many insults in specific ways
- ex. external wound vs. inhalation of pathogen
what are the 4 recognition mechanisms of innate immunity?
- rapid response (hours)
- fixed
- limited number of specificities
- constant during response
what are the 4 recognition systems of adaptive immunity?
- slow response (days to weeks)
- variable
- numerous highly selective specificies
- improve during response
T or F
the innate and adaptive immune systems work together to fight infections
true
what are the 6 cells of innate immunity?
- granulocytes
- neutrophil
- eosinophil
- basophil
- monocytes
- macrophage
- dendritic cell
- mast cell
what are the 4 cells of adaptive immunity?
- lymphocytes
- T cells
- B cells
- NK cells
- dendritic cells
describe primary lymphoid organs
- where immune cells originate and develop
- tissues
- bone marrow and thymus
describe secondary lymphoid organs
- where adaptive immune responses are initiated
- where naive and mature B and T cells reside
- tissues:
- lymph nodes, spleen, lymphatic system, organ-specific lymph node-like tissues
immune cells use the ___ and ___ systems to reach tissues
cardiovascular and lymphatic
describe lymphatic recirculation
- immune cells use the cardiovascular system and lymphatic system to reach tissues
- naive lymphocytes arrive at lymph nodes in arterial blood
- pathogens from the site of infection reach lymph nodes via lymphatics
- lymphocytes and lymph return to the blood via the lymphatics
- venous blood returns to the heart
the adaptive immune system comes from a common ___ precursor
lymphoid
the innate immune system comes from a common ___ precursor
myeloid
the lymphatic system is a large ___ network
duct
lymphocytes, NK cells, monocytes, granulocytes, and mast cells are collectively called what?
leukocytes
what is lymph?
interstitial fluid that drains into the lymphatic system, and includes cells, pathogens, and waste
the flow of lymph is ___
unidirectional
describe the unidirectional flow of lymph
- valves
- smooth muscle
- pressure gradient
- drains into the venous system
lymph nodes allow ___ to browse drainage
lymphocytes
what are the three stages of the generalized response to infection?
- immediate innate
- induced innate
- adaptive
what are immediate innate systems involved in the inflammatory response?
- barriers
- antimicrobial peptides
- complement
describe the process of the inflammatory response?
- surface wound introduces bacteria, resident effector cells are activated to secrete cytokines
- fluid, protein, and inflammatory cells leave blood and enter tissue
- infected tissue becomes inflamed, causing redness, heat, swelling, and pain
describe the induced innate immune response
- neutrophils are stored in the bone marrow and are released when needed to fight infection
- they enter the infected tissue, where they engulf and kill bacteria
- neutrophils die in the tissue and are engulfed/degraded by macrophages
what are the 7 cell types of the induced innate immune response?
- neutrophils
- monocytes
- macrophages
- dendritic cells
- basophils
- eosinophils
- mast cells
- NK cells
of the induced innate cell types, which ones are resident in the tissue but require activation?
basophils, eosinophils, and mast cells
what are the 3 primary antigen presenting cell types?
dendritic cells, macrophages, and B lymphocytes
describe how naive lymphocytes are activated in lymph nodes
- mature, naive T and B cells reside in lymph nodes
- pathogens are presented to lymphocytes in lymph nodes
- activated lymphocytes travel from lymph nodes to infected tissues
___ activates lymphocytes
- antigen presentation by dendritic cells, macrophages, or B lymphocytes
- leads to clonal selection and expansion
lymphocytes have a functionally infinite capacity for ___
antigen recognition
lymphocyte antigen specificty ___ over time
improves
___ cells preserve the ability to recurrently respond to an antigen
memory T and B cells
which cells kill pathogenic self cells and regulate the immune response?
T cells
describe how cytotoxic (CD8) T cells kill pathogenic self cells
recognizes complex of viral peptide with MHC class I and kills infected cell
describe how regulatory (CD4) T cells kill pathogenic self cells
- Th1 cell recognizes complex of bacterial peptide with MHC class II and activates macrophage
- helper T cell recognizes complex of antigenic peptide with MHC class II and activates B cell
describe how B cells produce antibodies
- a resting B cell encounters an antigen
- the B cell is stimulated and gives rise to antibody-secreting plasma cells
- plasma cells secrete antibodies into the blood and tissues
antibodies are targeted against a single ___
antigen
what is the normal response and deficient response to an infectious agent?
- normal response - protective immunity
- deficient response - recurrent infection
what is the normal response and deficient response to an innocuous substance?
- normal response - allergy
- deficient response - no response
what is the normal response and deficient response to a grafted organ?
- normal response - rejection
- deficient response - acceptance
what is the normal response and deficient response to a self organ?
- normal response - autoimmunity
- deficient response - self tolerance
what is the normal response and deficient response to a tumor?
- normal response - tumor immunity
- deficient response - cancer
