Question

What is a key immune response needed to defend against multicellular parasites?

a.
Activation of TH1 response leading to production of IgG necessary for activation of mast cells and basophils.

b.
Activation of TH2 response leading to production of IgE necessary for activation of mast cells and eosinophils.

c.
Activation of B-cells to produce secreted IgA necessary for mucosal immunity against parasites.

d.
Activation of neutrophils and macrophages because parasites are primarily cleared by the activity of phagocytic cells.

e.
Activation of strong inflammatory responses because parasite antigens are highly antigenic.

Answer 1

The immune response needed to defend against multicellular parasites b. Activation of TH2 response leading to production of IgE necessary for activation of mast cells and eosinophils. Therefore, b. Activation of TH2 response leading to production of IgE necessary for activation of mast cells and eosinophils is correct .

The key immune response needed to defend against multicellular parasites involves the activation of the TH2 response and the production of IgE antibodies.

Option (b) correctly describes this process. Here's a more detailed explanation:

Multicellular parasites, such as helminths (worms), trigger a specific type of immune response mediated by T-helper 2 (TH2) cells.

TH2 cells release cytokines that stimulate B-cells to produce immunoglobulin E (IgE) antibodies.

These IgE antibodies, in turn, bind to the surface of mast cells and eosinophils.

Mast cells and eosinophils play crucial roles in the defense against multicellular parasites.

When IgE antibodies on the surface of mast cells encounter parasite antigens, they trigger the release of inflammatory mediators, such as histamine.

This inflammatory response is effective against parasites and helps to expel them from the host.

Eosinophils, activated by IgE antibodies, release toxic substances that are particularly effective against parasites.

These cells are capable of attacking and destroying multicellular parasites directly.

Options (a) and (c) are not accurate for defense against multicellular parasites.

Option (a) mentions the TH1 response and IgG, which are more associated with intracellular pathogens.

Option (c) refers to secreted IgA, which is more involved in mucosal immunity but may not be the primary defense against multicellular parasites.

Option (d) mentions the activation of neutrophils and macrophages, which are more commonly associated with bacterial and fungal infections rather than multicellular parasites.

Option (e) suggests activation of strong inflammatory responses, but the key lies in the specific activation of TH2 and the production of IgE antibodies for an effective defense against multicellular parasites.