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Unit 9: Immunity and Vaccines - Coggle Diagram
Unit 9: Immunity and Vaccines
First Line Defenses
Types of first defenses
Body borders
Digestive and respiratory track
Physical barriers
Skin
Mucous membranes
Antimicrobials
Salt, lysozyme, peroxidase, defensins, acidic surroundings, bile
Nutritional immunity
Transferrin, lactoferrin, haptoglobin (iron), albumen and calprotectin (zinc)
Microbial helpers
Commensal microbiota
Innate immunity
Self and non-self recognition
Molecules made by microbes but are not found in animals
Complement system
How it is activated
3 pathways that lead to the formation of C3 convertase
Classical, alternative and lectin pathway
Outcomes
Opsonization
Inflammatory response
Lysis of foreign cells
Immune cells
Leukocytes
Neutrophils
Engulf and destroy bacteria and other material
Granules, polymorphonuclear
Macrophages and dendritic cells
Engulf material in tissues, destroy invaders
Always present in tissues
Cytokines
Allow cells to communicate
Released in combinations
Chemokines, proinflammatory and regulatory cytokines
Response to microbes
PRRs (microbial products)
DAMPs
TLRs
NLRs (rec PRRs and DAMPs)
RLRs (rec viral RNA)
Inflammatory response
Dilation of small blood vessels
Migration of leukocytes from bloodstream to tissues
Dead neutrophils, tissue debris accumulate as pus
Fever response
Strong indicator of infectious disease (especially bacterial)
Pathogen growth rate is reduced and enzyme rates increase
Adaptive immunity
T cells
mediate cellular immunity
each has a unique receptor (TCR) that recognizes a single antigen
Cytotoxic and helper T cells
B cells
mediate humoral immunity
each produce a single type of antibody
unique receptor (BCR) that binds only to a single antigen
differentiate into plasma cells (produce antibodies) or memory B cells
Antibodies/immunoglobulins
Proteins generally elicit strong responses
Epitope - small region of larger antigen that is actually bound by antibody
Mark antigens as foreign --> phagocyte activation
Takes a week or more to build following first exposure
Response has specificity for a single pathogen
Primary response
takes 10-14 days for substantial antibody accumulation and then making copies of T and B cells
Secondary response
Faster, more effective than primary. More memory B cells with the right receptors
Humoral immunity
works to eliminate extracellular threats (bacteria, toxins, viruses in bloodstream)
Cell-mediated immunity
deals with targets that reside within a host cell (virus infecting cell)
Antigen
molecular target of the immune response
antibody generator
T-dependent (require helper T cells) and T-independent
Vaccines
Active immunity
natural active immunity (exposure to an infectious agent)
Artificial active immunity (vaccination)
Passive immunity
Natural passive immunity (antibodies transferred between baby and mother)
Artificial passive immunity (antibodies from other people or animals transferred to an individual - not long term)
Herd immunity
develops when a critical portion of population is immune to disease, infectious agent is unable to spread due to insufficient susceptible hosts
Attenuated vaccines
weakened form of pathogen
naturally mutated or genetically manipulated to replace normal genes
long-lasting immunity, need to be administered once
can occasionally revert or mutate, become pathogenic
hard to manage
Inactivated vaccines
Not viable, so unable to replicate, but retain immunogenicity of pathogen or toxin
cannot cause infections or revert to pathogenic forms
immune response is limited because no amplification happens in vivo
several booster doses usually needed
terms
toxoids - inactivated toxins
subunit - key protein antigens or antigen fragments from pathogen
VLP - empty capsid
polysaccharide capsule
conjugate - polysaccharides linked to proteins
immunological testing
seronegative - individual not yet exposed to antigen
seropositive - individual has produced specific antibodies to pathogen