allergies

Question 1

what is an allergic reaction

Answer 1

A hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in most people

Question 2

what is vascular reaction to allergens( how blood cells respond to stimulus)

Answer 2

is classified as immediate hypersensitivity after an antigen has appeared to some who is sensitive to it.

Question 3

what immune cells are present in a reaction

Answer 3

neutrophils, eosinophils and macrophages

Question 4

hallmarks of allergies

Answer 4

The production of IgE antibodies are dependent on activation of iL-4 producing T cells.

Requires previous T cell–dependent allergen-specific IgE production by B cells and the binding of the IgE to mast cells

Question 5

what is the order allergy happens in?

Answer 5

introduction of allergen
inflammatory response - inflammatory response stimulates IL-4
this produces helper T cell response and IgE production
IgE mast cells by bindng to FcR

Question 6

what causes inflammation?

Answer 6

Inflammation is caused by the introduction of an allergen that stimulates the IL-4-producing T cell response and IgE production. The IgE then sensitizes the mass cells by binding to the FcR and any further exposure to the allergen will activate the mast cells to secrete the mediators that are responsible for the pathologic reaction of the immediate hypersensitivity.

Question 7

what doe atopic individuals produce more of?

Answer 7

IgE

Question 8

what dont allergies simulate?

Answer 8

They don’t stimulate innate immune response that are associated with macrophages and dendritic cell secretion of Th1- and The17- inducing cytokines

Question 9

what causes anaphylactic response with food?

Answer 9

They are induced by glycated small proteins.

Question 10

cause of atopic dermatitis:

Answer 10

inherited deficiency keratinocyte protein

Question 11

what does TH2 do in atopic dermatitis?

Answer 11

 The differentiated Th2 cells migrate to tissue sites of allergen exposure.
 Contribute to the inflammatory phase of allergic reactions.
 Tfh cells remain in lymphoid organs, where they help B cells.

Question 12

activation of b cells and switching to Ige:

Answer 12

 B cells specific for allergens are activated by Tfh cells in secondary lymphoid organs
 In response to CD40 ligand and cytokines, mainly IL-4 and in some cases IL-13.

Question 13

what is normal concentration of IgE in plasma

Answer 13

1 µg/mL.

Question 14

what is the concertration of IgE in an atopic person?

Answer 14

1000 µg/mL.

Question 15

what is the role of Th2 cells and the innate lymphoid cells in allergic diseases?

Answer 15

 IL-4 secreted by Th2 cells induces expression of endothelial VCAM-1, which promotes the recruitment of eosinophils and additional Th2 cells into tissues.
 IL-5 secreted by Th2 cells activates eosinophils.
 IL-13 stimulates epithelial cells (e.g., in the airways) to secrete increased amounts of mucus, and excessive mucus production is also a common feature of these reactions.

Question 16

what are the properties of mass cells and basophils?

Answer 16

 Normally, mature mast cells are not found in the circulation.
 Progenitors migrate to the peripheral tissues as immature cells and undergo differentiation in response to local biochemical cues, including stem-cell factor released by tissue cells, which binds to the c-Kit receptor on the mast cell precursors.

Question 17

explain the binding of IgE to mast cells and Basophils?

Answer 17

 Mast cells and basophils express a high-affinity Fc receptor specific for ε heavy chains, called FcεRI, which binds IgE
 IgE functions as an antigen receptor on the surface of mast cells and basophils.