Put the following in the correct sequence to elicit an antibody response: (1) TH cell produces cytokines; (2) B cell contacts antigen; (3) antigen fragment goes to surface of the B cell; (4) TH recognizes antigen fragment and MHC; (5) B cell proliferates.
a. 1, 2, 3, 4, 5
b. 5, 4, 3, 2, 1
c. 3, 4, 5, 1, 2
d. 2, 3, 4, 1, 5
e. 4, 5, 3, 1, 2

Question

Put the following in the correct sequence to elicit an antibody response: (1) TH cell produces cytokines; (2) B cell contacts antigen; (3) antigen fragment goes to surface of the B cell; (4) TH recognizes antigen fragment and MHC; (5) B cell proliferates.
a. 1, 2, 3, 4, 5
b. 5, 4, 3, 2, 1
c. 3, 4, 5, 1, 2
d. 2, 3, 4, 1, 5
e. 4, 5, 3, 1, 2

a. 1, 2, 3, 4, 5

b. 5, 4, 3, 2, 1

c. 3, 4, 5, 1, 2

d. 2, 3, 4, 1, 5

e. 4, 5, 3, 1, 2

Accepted Answer

Hi everyone and welcome. Our next question says which of the following is not a step in the process of B cell activation as an A PC A binding and subsequent internalization of the antigen by B cells. B presentation of antigen fragments on MH C class one molecules by B cell. See recognition of antigen fragments by th cells on the B cell or D cytokine secretion by T cells that help activate the B cell. Well, these steps are almost correct in the correct order except for one problem. And that's with step B so or choice B. So that will be our answer for one. That is not a step because it says that the antigen fragments are presented by MH C class one molecules. Well, while the B cells just like every other kind of cell in the body have Mh C class one molecules. Those are for presenting internal um fragments if a cell were infected by something but the B cell in its role as an A PC or antigen presenting cell. Since that's what we're talking about here, we'll pres present the antigen fragments that it's internalized on MH C class two molecules. So the MH C class two molecules are for presenting external things that are encountered by the cell broken up inside it and presented as part of its role in the immune system. So that's why choice B is going to be our answer. So almost the right step but not quite to be thorough. Let's look at our other steps. Choice a binding and subsequent internalization of the antigen by B cells. This is the correct step along the way that initial encounter with the antigen, the B cell has those antibodies on its cell that bind specifically to the antigen, it's internalized and then those bits and pieces of it are what will be presented on the surface. So choice A is not our answer because it is a correct step. As we said in choice B, we have MH C class two molecules on the B cell that are what presents the antigen in its role as an A PC antigen presenting cell. Enjoy see recognition of antigen fragments by the TH cells. These are the helper T cells that are part of this process. So the B cells presenting this specific antigen, the helper T cell, which also is a specific binding binds to it as the next step along the way. So not our answer since that is a correct description and then finally choice D cytokine secretion by the TH cells. So once the T helper T cells abound, they release these cytokines which are sort of these alarm bells released out into the cell indicating they've been activated, they've encountered an antigen. So not our answer since that is a correct description. So once again, our answer, that is not a step in the process of B cell activation is choice B presentation of the antigen fragments on MH C class one molecules by A B cell because this should be MH C class two molecules in its role as an antigen presenting cell. See you in the next video.

Verified Solution

Key Concepts

Antigen Presentation

Cytokine Signaling

B Cell Activation and Proliferation