Basic Science of allergy

Question 1

Type II hypersensitivity mech.

Answer 1

Ab binds to antigen in tissue or on cell
1. antibody medicated tissue damage leading to inflammation - bullies pemphigoid

2. Direct antibody-mediated pathology-
   Drug induced hemolytic anemia
3. Binding to recepters -Hyperthyroidism, Myasthenia gravis

Question 2

Type III Hypersensitivity mech.

Answer 2

Complex forming

1. Systemic autoimmue diseases - lupus
2. Serum sickness
   - nonhuman protein (ex. antivenim) introduction
3. Poststreptococcal glomerulonephritis

Question 3

Live/attenuated vaccine

Answer 3

-long lasting response
-pt. may develop mild case of disease
-only need to give a few doses
Ex. MMR, Varicella zoster, rotavirus, intransasl influenza (LAIV), yellow fever, Vaccina (small pox), oral polia

Question 4

Inactivated vaccines

Answer 4

Dead pathogen

• not as strong an immune response
• more boosters needed

Question 5

macrophage

Answer 5

Phagocytosis
APCs
release cytokines
Innate immunity

Question 6

Neutrophil

Answer 6

Phagocytosis, but must be opsonized
degranulate and release pro inflammatory cytokines and free radicals
Innate immunity

Question 7

T-Lyphocyte

Answer 7

Helper T - sound alarm, initiated by APC and then active B cells
Also release cytokines
Cytotoxic T cells
Memory T Cells
Adaptive immunity
-toning down immune responses (how)?

Question 8

B-Lymphocytes

Answer 8

Start by expressing IgM
initiated by T helper, cause isotope switching and clonal expansion
- differentiate into plasma and memory cells
Adaptive

Question 9

Nature Killer (NK)

Answer 9

lymphocytes that are part of innate im

• can kill virus infected cells and cancerous
• can kill cells that don’t present MHC1
• don’t need activation

Question 10

Mast cell

Answer 10

cells that reside in mucosal tissues

• have granulas with histamine and vasoactive substances, eicosanoids, and cytokines
• cross link with IgE

Question 11

Atopy

Answer 11

tendency to be hypersensitive

Question 12

tolerance

Answer 12

T and B cells don’t react to body’s own proteins.

-tolerance needs to be learned in primary immune organs

Question 13

5 classes of immunoglobulins

Answer 13

IgA: secreted by mucosal fluids, GI tract, mothers milk
IgG: Vast bulk of serum antibody, only one that crosses the placenta
IgM: Acute phase antibody, first antibody made during infection. Pentamer
IgE: For worms and Helminths, important clinically for allergies and anaphylaxis.
IgD: Dr. Hill said not to worry about

Question 14

Neutralization

Answer 14

antibodies binds to microbe and prevents it from penetrating epithelial barrier

or prevents it from binding to cellular receptor

Question 15

opsonization

Answer 15

antibody binding to pathogen enables phagocyte to engulf it

Question 16

Complement activation

Answer 16

serum proteins that are activated in a sequential cascade.

Binding of antibody to antigen can trigger activation cascade

Leading to opsonization, cytolysis (Membrane Attack Complex punches holes in pathogen cell membrane), inflammation

Question 17

Type I - Hypersensitivity

Answer 17

• IgE antibody release in response to antigen
  -B cells differenciate to produce and release IgE
  -IgE circulates and attached to Fc portion of mast cells
  -in future, antigen returns, mast cell degranulates
  = histamine, eicosanoids, and chemokines

Question 18

Symptoms of Type I

Answer 18

• Response is generally localized
• Angioedema
• Laryngeal edema
• Allergic rhinitis
• Uriticaria
• Extreme - anaphylaxis

Question 19

MOA of allergic rhinitis

Answer 19

IgE combines with mast cells of respiratory passage
–mediators cause increased secretion of mucus
-increased blood flow, epithelial swelling
-contraction of smooth muscle surround airways
Symptoms: congestion, runny nose, sneeze, respiratory difficulty