immune responses Flashcards
type 1 hypersensitivity , which immune components are involved
IgE
mast cells
basophils
examples of type 1 conditions
anaphylaxis
asthma (allergic)
allergic rhinitis (hayfever)
food and drug allergies
describe what happens in type 2 hypersensivity
IgM and IgG bind to self-cells causing them to be destroyed by immune cells (NK cells or complement)
cells involved in type 2 hypersensivity reactions
IgM, IgG
component
NK cells
cytotoxic
examples of type 2 hypersensitivity
AIHA
good pastures (Anti-GBM)
graves
myathensia gravis
rheumatic fever
most abundant WBC
neutrophils
short lifespan 6-8 hours
neutrophils play a main role in which part of the immune system?
innate immune system - immediate response to bacterial infections
explain type 3 hypersensivity reactions
complexes
inmmune complexes form (antigen-antibody) and are deposited in tissues
causing inflammaiton and tissue damage
cells involved in type 3 hypersensitivity responses
IgG
immune complexes
complement
neutrophils
examples of type 3 hypersensitivity conditons
SLE
RA
Post-streptoccal GN
Vasculititis - e,g, polyarteritis nodosa
describe type 4 hypersensitivity
DELAYED
T-cells release cytokines
activate macrophages and cause tissue damage OVER TIME
cells involved in T4 hypersensivity
T-cells CD4 and CD8
macrophages
comon T4 hypersensivity conditions
T1DM
MS
Contact dermatitis - poision ivy
TB - skin (mantoux test)
Crohns disease
: Fast allergic reactions (IgE-mediated) → anaphylaxis, asthma.
what response
T1
Antibody-mediated cell destruction (IgG/IgM) → hemolytic anemia, Graves’ disease.
what response?
T2
Immune complex-mediated inflammation → lupus, rheumatoid arthritis.
Type 3
T-cell-mediated delayed response → type 1 diabetes, multiple sclerosis.
type 4
what are the two phases of T1 hypersensitivity response
- Sensitization Phase (First Exposure to Allergen)
- Effector Phase (Subsequent Exposure & Histamine Release)
dendritic cells or macrophages are APC
a. true
b. false
a. true
APCs process the allergen and present it on their surface using MHC class II molecules.
r
responsible for generating most fever symptoms
IL-1
major enodgenous pyrogen
sereted by macrophages -to stimulates, T/B cellls and neutorphils
pyogenic
refers to anything that produces pus or is associated with pus formation
-> indicates bacterial infection -> pus consists primilariy of expended neutrophils
most specific antibody for SLE
anti-double stranded DNA
antibodys associated with syjogrens
anti Ro/La
antibody associated with systemic scelrosis
Anti-centromere
most specific antibodies of Rheumatoid arthritis
anti-citrullinated peptide antibody (CCP)
severe combined immunodeficiency is ?
dimisnished T cells / abnormal B-cells
BOTH affecteded
Xlinked or autosomal
low total lymphocyte count < 2
What is Burtons disease (agammaoglobuinaemia)
NO B-cells
Xlinked
BTK mutation in burton tyrosine gene
wiskott aldrish syndrome - what is it
X linked
b and t cell dysfunction
WASP gene mutation
(bacterial infections, eczema, thrombocytopenia - bleeding)
hyper-IgM syndrome
X linked
- can only produce IgM
cannot differieniate
absence of B-cells
burtons (agammaglobulinaeamia)
selective IgA deficiency is associated with
coeliac disease
hyper IgM syndrome
X-linked
can only produce IgM
failure to deferientiate
wiskott aldrish syndrome
X linked
low B and T cells
- infection
- ecemza
- bleeding
most common primary immunodeficiency
common variable immunodeficiency
causes of decreased antibody production
malnutrition
drugs
malignancy
infection
causes of antibody loss
nephrotic syndromes
burns
protein losing enteropathy
features of thalassaemia
jaundice, splenomegaly
poor growth and development
pathophysiology of sickle cell
Autosomal recessive condition causing mutation on HBB gene on chromosome 11,
forming HbS
Results in crescent shaped RBCs, which are more prone to destruction & can block vessels
diagnosis of sickle cell
New born screening @ 5 days
Definitive diagnosis is by haemoglobin electrophoresis
management of sickle cell
Hydroxycarbamide – increases HbF production
Pneumococcal vaccine every 5 years
painful sickle cell crisis
Obstruction of vessels by sickle cells
Triggered by dehydration, infection and deoxygenation (high altitude)
acute chest syndrome
Dysponea, chest pain, low PO2,
pulmonary infiltrates on CXR
Emergency – hydration, antibiotics, resp support and analgesia
aplastic crisis in sickle cell
Sudden drop in haemoglobin
Can be triggered by parvovirus B19
Supportive management, transfusion may be required
how is haemophilia inherited
X linked recessive disorder
A – VIII, B – IX
presentation of haemophilia
problem with clotting factors - secondary haemostasis
- Hemarthrosis (bleeding into joints - swollen knee)
- Intracranial bleeds, cord bleeding
- Prolonged bleeding
what is passive immunity
where a person receives pre-formed antibodies rather than producing them through their own immune system. This provides immediate but temporary protection against infections.
- natural - from mother
- injection of antibodies
what is natural passive immunity
**Transfer of antibodies from mother to baby
**
- Placental IgG transfer during pregnancy
- Breast milk (IgA)
takes Weeks to months (until antibodies degrade)
what is artifical passive immunity
**Artificial Passive Immunity Injection of antibodies -
**
- Antitoxins (e.g., tetanus, diphtheria antitoxin)
- Monoclonal antibodies (e.g., COVID-19 treatment,
RSV prevention) - Immune globulin therapy (e.g., Rabies, Hepatitis B immunoglobulin)
Short-lived (few weeks to months)
characteristics of passive immunity
✔ Immediate protection – Useful in emergency infections.
✔ No memory response – Does not activate the recipient’s immune system.
✔ Temporary – Antibodies degrade over time, requiring repeated administration if needed.
What molecule trigger type 1 hypersensitivity reactions?
IgE
what is active immunity
Immunity produced by the body in response to infection or vaccination.
The body produces its own antibodies.
active immunity results in creation of memory cells
a. true
b. false
a. true
Yes, the body creates memory cells that remember the pathogen and respond faster upon re-exposure.
helps in long-term protection.
speed of response in active immunity
Slower, as the body needs time to recognize and fight off pathogens and produce antibodies.
key difference in active/passive immunity
Active immunity is the body’s natural or vaccine-induced response that creates lasting protection and memory.
Passive immunity is short-term and doesn’t involve the body’s immune system creating its own response; it relies on receiving ready-made antibodies from an external source.
origin of b-cells and where mature
bone marrow
function of b-cells
humerol immunity = produce antibodies
what activates b-cells
antigens or Th cells (t-helper)
b-cells and t-cells can form memory cells
true
types of B cells
plasma cells
memory cells
b cells interact with MHC
a. true
b. false
b. false
function of t-cells
Cell-mediated immunity (kill infected cells, help B cells)
how are t- cells activated
APCs antigen presenting cells
do t-cells have memory cells
yes
types of t-cells
helper t cells
cytotoxic
regulartoy
do t-cells interact with MHC
yes
both class I and II
response time of innate immune system
Immediate (minutes to hours)
response time of adpative immune system
Delayed (days to weeks)
specity of innate immune system
Non-specific, recognizes general patterns (e.g., PAMPs)
specificity of adapative immune system
Highly specific to individual pathogens
memory of innate immune system v adapative
innate- - No memory (response is the same each time)
adaptive - Has memory (faster and stronger response upon re-exposure)
components of innate immune system
Physical barriers (skin, mucous membranes), phagocytes, NK cells, complement system
components of adaptive immune system
T cells, B cells, antibodies, antigen-presenting cells
how is the innate system activated
Triggered by pathogen-associated molecular patterns (PAMPs)
how does the innate system respond
Inflammatory response, phagocytosis, complement activation
speed of activation of adapative immune system
Slower, requires time for activation and differentiation
main cells in innate immune system
Neutrophils, macrophages, dendritic cells, NK cells
First line of defense, prevents spread of pathogens
innate immne system
Phagocytosis, inflammation, complement system
innate immune system
Antibody production, cell-mediated cytotoxicity
adaptive immune system
response time T4 reactions
48-72 hours
response time of T2 and T3 reactions
hours to days
varies
response time of T1 reactions
immediate
mediators of T4 reactions
T cells (CD4 and CD8)
T cells cause tissue damage through inflammation
Immune complexes deposit in tissues, causing inflammation
is what hypersensitivity?
T3
IgG nd IgM complexes with antigen
SLE/RA
Antibodies target cells, causing destruction
is what reaction
T2
Haemolyic anaemia
good pastures - anti-GBM
IgM and IgG target self-cells
