Immunity Flashcards
Function of immune system
Body’s defense against
1. pathogens (viruses, bacteria, fungi, parasites)
2. environmental pathogens (poison ivy)
3. toxins
4. abnormal body cells (cancer)
Immunity is…
The ability to resist infection and disease
What is innate (nonspecific) defenses
Immediate response to harmful agents that doesn’t require a previous exposure to a foreign substance
What responds first in innate defenses?
Skin, mucus membranes, inflammation, GI system, cellular response
True or False? We are born with innate defenses
True
What role do adaptive (specific) defenses play?
Identifies, attacks, reinforces, and amplifies immunity to a SPECIFIC pathogen
What is a major player in the adaptive immune defense?
Lymphocytes
True or False? adaptive immune defenses develop with time and exposure
True
Where do T-lymphocytes mature?
Thymus
Where do B-lymphocytes mature?
Bone marrow
What is inflammation?
immediate, local, and non-specific response
response is to injury, not just infection (ex: allergy, twisted ankle)
increased blood flow to the site, increase capillary permeability. attracts cells of immunity
What role does histamine, prostaglandins, leukotrienes, and bradykinin in inflammation?
Causes vasodilation and increase in capillary permeability
Effects of histamine
Increase capillary permeability, vasodilation, bronchoconstriction, increase nasal and mucus secretion, stimulates sensory receptors (ex: increase itching)
What could go wrong if inflammation goes too far?
damage to healthy cells, low blood pressure from vasodilation, swelling in brain or larynx (inappropriate swelling)
Acute inflammation
either resolved, leads to scarring/fibrosis, can progress to chronic inflammation
Chronic inflammation
result of recurring or progressive acute inflammatory responses
this response often has infiltration of macrophages, lymphocytes, plasma cells, attempted connective tissue repair involving angiogenesis and fibrosis (tissue damage)
Examples: rheumatoid arthritis, lupus, chronic pancreatitis, chronic hepatitis
What cells are the first to respond during innate immunity?
Neutrophils
What cells fight worms/parasites?
Eosinophils
Where are monocytes found and what do they become?
In blood; become macrophages and dendritic cells
What are dendritic cells?
antigen presenting cells
what are the 3 protein systems?
complement, clotting, kinin
what does the complement system do?
opsonizes pathogens (coats bacteria and provides handles for grabbing onto), kills pathogens by perforating cell, amplifies inflammatory response
What does the kinin system do?
enhances inflammatory response (vasodilation, smooth muscle contraction, vascular permeability), along with prostaglandins (inflammatory response) stimulates pain receptors
what are the two antigen presenting cells and what do they do
dendritic cells and macrophages; digest invading microbe and present antigen to lymphocytes in lymphoid organs
What is produced after first exposure to pathogen?
Memory t and b cells
what makes up cellular immunity and where do the cells mature?
T-cells, CD8 cells (killer t cells), CD4 cells (helper t cells), mature in thymus
what cells make up humoral immune response and where do they mature
b-cells (produced by plasma cells), mature in bone marrow
IgG
most effective antigen, can cross placenta
IgE
allergy (think IgE allerygyyyy), increase in IgE during allergic reaction
IgM
indicates a recent infection, earliest antibody produced
IgA
found in breast milk, secreted in mucus
Active immunity
immune system creates response due to infection or vaccination
passive immunity
immunity is transferred from another source; ex: antibodies for covid, 1st rabies vaccine, maternal antibodies passed to fetus
What is the only immune globulin to cross the placenta?
IgG
True or false? antibody tests tell you that you have an infection
false, they just tell you if you’ve ever been exposed and have antibodies for it
When does the immune system become competant?
near birth
What does the major histocompatibility complex (MHC) proteins on cell surface allow
immune system to recognize self
autoimmunity causes
immune system to damage self
example: crohn’s disease, multiple sclerosis, type 1 diabetes mellitus (cannot control glucose)
what are the four types of hypersensitivity reactions
Type 1: IgE mediated (allergic reaction)
Type 2: antibody mediated (IgG and IgM)
Type 3: immune complex (clumps of antigens and antibodies where not supposed to be)
Type 4: T-cell mediated (takes time)
Type 1 hypersensitivity
allergic response, atopic persons (immune system is more sensitive to allergic triggers; higher levels of IgE), excessive release of inflammatory mediators
anaphylaxis
produces a systemic reaction, local effects include rash, hives, swelling of tongue or uvula, rhinorrhea (excessive drainage), pruritus (itching)
inhaled allergen causes
respiratory symptoms (bronchoconstriction - wheezing)
ingested allergen causes
GI symptoms (nausea/vomiting, cramps)
anaphylactic shock
systemic response to allergen, causes widespread histamine release (systemic vasodilation, capillary leakage, smooth muscle constriction, shock state, airway obstruction and cardiopulmonary collapse)
Can antihistamine help anaphylactic shock?
no, no immediate effect on reaction
what is the primary mechanism of control for anaphylactic shock?
autonomic nervous system
what medication is most effective for anaphylactic shock?
epinephrine (vasoconstriction, dilates bronchioles)
Type 2 hypersensitivity reactions
produces antibodies that recognize self antigens and bind to them, direct attack on cells and tissues, can be triggered by an infection, can cause cell lysis, inflammation, or inappropriate cell response
examples: graves disease (hyperthyroidism), RBC transfusion reactions, acute rheumatic heart disease
Type 3 hypersensitivity
immune complex mediates, antibodies form complexes with antigens, complexes lodge into body tissues
examples: post-strep glomerulonephritis, allergic alveolitis
where is a common site for type 3 hypersensitivity to occur
kidneys bc filtering a lot of blood, other sites include joints and blood vessels
type 4 hypersensitivity
T-cell mediated (CD4 and CD8), delayed reaction (ppd TB test for ex), phagocytes and CD8 cells attack body tissue leading to tissue destruction
examples; contact dermatitis, type 1 diabetes, crohn’s disease, MS, poison ivy
True or false? antihistamines are the first line therapy for type 4 (IV) reactions
False, not mediated by histamine
autoimmune disorders
results from breakdown in self-tolerance, immune system produces autoantibodies (attack host cells), can occur in families
where is central tolerance established
established in bone marrow and thymus
what maintains peripheral tolerance
t-regulator cells in secondary lymphoid tissue
Immunosupression
arises from impaired immune function, one or more components of immune system compromised, can be innate or adaptive including deficiency in lymphocytes (t or b cells), phagocyte defects, complement deficiencies
primary immunodeficiencies
born w it
example: born w/out thymus
secondary immunodeficiency
acquired over time
example: immunosuppression due to chemotherapy
what causes Human acquired immunodeficiency syndrome (HIV)
human immunodeficiency virus (HIV)
what does HIV primarily infect
CD4 T helper cells
characteristics of HIV
retrovirus that carries genetic material in RNA rather than DNA
also is a slow virus, having a long time period between initial infection and serious symptoms (can remain latent for 8-10 years)
what conducts the entire immune response?
T-helper cells
how does HIV infect and replicate in host cells
viral envelope has a glycoprotein, this molecule binds to CD4 receptor on T helper lymphocytes, macrophages and dendritic cells
what 3 important enzymes that aid in HIV replication
reverse transcriptase, integrase, protease
What is the clinical significance of the HIV life cycle?
to try and stop it, new drug therapy
common ways to get HIV
sexual contact, contaminated blood products, contaminated needles, mother to fetus
clinical manifestations of HIV
flu like symptoms 1-2 weeks post exposure; 8-10 years between HIV infection and AIDS diagnosis
what antibody shows up first in HIV infection and which one does it switch to?
IgM first then IgG
what does a high viral load mean
in a state of infection, can be infectious to others
what does an undetectable viral load mean
non-transmissable
