Host defense-1 Flashcards
functions in NORMAL host without prior expose to invading microbes
Innate Response
consists of antibody response(humoral) and lymphocyte mediated response (cell mediated) response-tailored to particular microbial infection and characterized by memory?
Adaptive Response (due to prior exposure to pathogen)
Adaptive, specific immune responses are induced by?
exposure to an antigen
Adaptive specific immune response is specific for?
inducing antigens and then immunologic memory is generated
Using the military analog as an example…describe the immune response and details that coincide with that response?
- Invading pathogens
- Barrier to prevent invading pathogens
- innate immune defense standing guard
- Messenger to relay information to the organized lymphoid tissue(where the pathogens want to invade) and adaptive immune army
- Adaptive immune army to act as reinforcements to the innate immune defense
How long does innate immunity generally take?
Very quick! Within minutes or hours
How long does acquired Adaptive immunity take?
Longer than innate immunity, can take DAYS or even weeks depending on the specific antigens
Describe the diversity of innate immunity?
A limited number of germ line encoded receptors
Is there any memory responses for innate immunity?
None
Self/nonself discrimination of innate immunity?
Perfect; no microbe specific patterns in host
Soluble components of innate immunity?
Many antimicrobial peptides and proteins
Major cell types of innate immunity?
Phagocytes (monocytes, macrophages, neutrophils), natural killer (NK cells), dendritic cells
Specificity of adaptive immunity?
Highly specific, discriminates even minor differences in molecular structure, details of microbial sor non-microbial structure recognized with high specificity.
Diversity of adaptive immunity?
Highly diverse, a very large number of receptors arising from genetic recombination of receptor genese
Memory response from adaptive immunity?
Persistent memory with faster response of greater magnitude on subsequent infection
Self/nonself discrimination of adaptive immunity?
Very good, occasional failures of self/nonself discrimination result in autoimmune disease
Soluble components of blood or tissue fluids in adaptive immunity?
Antobodies
Major cell types of adaptive immunity?
T cells, B cells, antigen presenting cells
Innate immunity is comprised of?
- Constitutional factors
- Natural barriers and normal flora
- Cytokines/Interferons
- Phagocytosis
- Complement (which is technically in both innate and adaptive immunity)
Aspect of innate immunity that make one species innately susceptible and another resistant to certain infections?
Constitutional factors
What are some constitutional factor examples?
- Genetic: between species
- Age: the young more susceptible
- Metabolic factors: hypoadrenal and hyperthyroid states
- Neuroendocrine factors
- Environment: malnutrition, poor living conditions, overcrowding
3 different defenses against natural barriers and normal flora?
- Mechanical
- Chemical
- Microbiological
Natural mechanical barrier of skin?
Flow of fluid perspiration, sloughing off skin
Also epithelial cells joined by tight juntions
Natural Chemical barrier of skin?
Sebum (fatty acids, lactic acid, lysozyme)
Also antimicrobial peptides (defensins which are really short) effective against some microbes
Natural Microbiological barrier of skin?
Normal florida of the skin
Normal flora and their waste stimulates?
Immune stimulation
What are some things that decrease normal flora leaving the host more susceptible to disease?
- Antimicrobial drugs (allow for susceptibility because disease does not have to compete for attachment sites for essential nutrients because normal flora was taken out) “Double edge sword”
- Host factors such as reduced peristalsis, immune suppression
- Physical destruction from things such as irradiation and chemical burns
Cytokines/interferons major function of this type of interferons (IFN)
Type 1 interferons (“which are very important against viral infections”)
Type types of Type 1 interferons, name them and their alternative name?
- Interferon alpha-Leukocyte interferon
- Interferon beta-Fibroblast interferon
Principle producer cells of interferon alpha and beta?
Leukocytes, fibroblasts, macrophages, epithelial cells
Inducing agents of interferon alpha and beta?
Viruses, double stranded RNA
Major activity of interferon alpha and beta?
Antiviral action (both)
IFN system (Type 1 interferon) is crucial for?
Antiviral Defense
Main idea of the IFN system chart?
if you generate more type 1 interferon those mice are more susceptible to viral infections
Phagocytic cells that are involved in the defense against microbes include?
- Polymorphonuclear neutrophils
- Mononuclear phagocytes: (monocytes in blood, macrophage in tissue)
- Eosinophils
(REMEMBER that NEUTROPHILS are NOT phagocytes but rather they are capable of phagocytosis along with phagocytic cells)
Lymphocytes like B cells and T cells, and Large granular lymphocytes like nulls cells or natural killer cells are responsible for?
FYI:
(NK cells apart of nonspecific or innate immune response)
- Antibody producing plasma cells
- Cell mediated immune response
- Helps B cells in antibody production
- Kill other rogue cells in a nonspecific manner
Engulfment and digestion of infectious agents or other foreign bodies by phagocytic cells
Phagocytosis
Examples of phagocytic cells?
Phagocytes and neutrophils
5 steps of multiphasic Phagocytosis?
- Bacterium becomes attached to membrane evaginations called pseudopodia
- Bacterium is ingested forming phagosome
- Phagosome fuses with lysosome
- Lysosomal enzymes digest captured material
- Digestion products are released from cell
Name the immune system?
Contain pattern recognition receptors(PRRs) such as toll like receptors, rig like receptors and complement
Also missing/altered self receptor Natural killer cells
Innate immune sustem
Name the immune system?
- Antigen presentation (MHC)
- Antibodies
- T-cell receptors
Adaptive immune system
PRR: Pattern recognition receptors like toll like receptors (one of many examples of PRRs) can recognize this?
PAMP: pathogen associated molecular patterns
Macrophages are a type of?
PRR: pattern recognition receptor
Macrophages express several receptors specific for bacterial constituents, the bacteria bind to the macrophage receptor and then the macrophage engulfs and digests the bound bacteria
Macrophages and neutrophils can use these two mediators to phagocytize bacteria?
- Oxygen dependent killing
- Oxygen independent killing
Live only one day within tissue, their primary function is to phagocytize and kill extracellular bacteria and yeasts pathogens in acute inflammation?
Neutrophils
Dead neutrophils are cleaned up by?
Macrophages
Along with bacteria, neutrophils express receptors for?
fungal constituents
After neutrophil binds to bacteria, what do they do differently from macrophages?
engulf the bacteria and destroy them with the toxic contents of the neutrophil granules.
Within the host, there is a pool of neutrophils stored within the?
Bone Marrow
When they are needed those neutrophils will be released and migrate to the site of inflammation to fight infection (acute inflammatory response). Neutrophils travel and enter the infected tissue where they engulf and kill bacteria. the neutrophils die in the tissue and are engulfed and degraded by macrophages
name for granulocytosis involving neutrophils=bacterial infection
Leukocytosis
What comprises 1-3% of Eosinophils?
White blood cells
What happens to eosinophils when PARASITIC infection takes place and patient has type 1 hypersensitivites.
Easinophils increase in numbers
What type of parasite are eosinophils important for defending against?
defense against Helminths
Large, granular lymphocytes that play a very important role in antiviral infections?
Natural Killer cells (NK cells)
What happens to NK cells after detection of viral infection?
Numbers increase rapidly because they are stimulated to divide by IFN
What is produced by infected cells and dendritic cells after detection of virus from natural killer cells?
IFN
How do natural killer cells “Kill”?
By releasing perforins and granzymes that perforate membranes and trigger caspace mediated cell death
Two types of receptors for Natural killer cell recognition of infected cells: “Detection of altered self” and provide a brief description of what is caused?
- Inhibitory receptor engaged which causes the NK cell to not be activated so this will result in NO cell killing (blocks)
- Inhibitory receptor not engaged, activating receptor engaged which causes the NK cell to be activated with does cause killing of the infected cell
Name the “virus infection associated ligand” for blocking?
MHC I molecule
Virus infection associated ligand causes this action?
activating
Who are the prime targets for Natural killer cells?
Virus infected cells
Clicker
What are the natural killer cells?
- Lymphocytes
- Recognizing “altered self” with decreased MHC I molecules on surface
(True or False) Phagocytic cells use pattern recognition receptors for pathogen recognition?
True
