20. Adaptive Immunity
Primary and Secondary Response of Adaptive Immunity
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concept
Primary and Secondary Response of Adaptive Immunity
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in this video we're going to begin our lesson on the primary and secondary responses of adaptive immunity. And so what's important to recall from some of our previous lesson videos is that the memory cells specifically the memory B cells and the memory T cells are really important for generating an adaptive immune response towards future infections. But they're not really involved with the primary or the initial infection. And so here what we're telling you is that these memory B cells and memory T cells are actually capable of making a secondary adaptive immune response significantly faster and significantly more effective. Then the primary immune response or the initial immune response when your first responding to an antigen for the very first time. And so down below we distinguish between the primary immune response and the secondary immune response. And so the primary immune response as its name implies is referring to a relatively slower and weaker immune response upon initial exposure to an antigen or the very first time that you were exposed to an antigen. Your immune response will be slower and weaker. And so for example it's actually going to take more time in order to produce a relatively low number of antibodies, a relatively low number of I. G. M. Antibodies and a relatively low number of I. G antibodies. For example. Now the secondary immune response as its name implies is going to be referring to a significantly faster and stronger immune response upon a secondary exposure to an antigen or the second time that you were exposed to the same antigen. Your immune response will be significantly faster and significantly stronger allowing your body to eliminate the antigen more effectively. And so for example it's going to take significantly less time to produce a relatively high number of I. G. Antibody. The more effective antibody and only some I. G. M. Antibody. And also the secondary immune response is associated with the memory B. And T. Cells of adaptive immunity. And so really it's these memory B. And T cells that allow for the faster and stronger immune response. And so if we take a look at our image down below we can further differentiate between the primary immune response which we have on the left hand side over here and the secondary immune response which we have on the right over here. And so what you'll notice about this graph is that on the X axis here we have time in weeks and on the Y axis. What we have is the antibody concentration in the blood serum or how many antibodies there are. And what you'll notice is that here when we are initially exposed to an antigen Okay at time zero here when were first exposed for the very first time to a specific antigen? It can take multiple weeks in some cases for your body to be able to produce antibodies and notice that the very first class of antibody that's going to be produced initially is the I. G. M. Antibody which you might recall. That was one of the important details you should know about the I. G. M. Antibody that it's the very first initial class that's going to be produced. Uh and notice that antibody class switching will allow for um the B cells and plasma cells to switch from releasing I. G. M. To switch to releasing a more effective antibody in this case the I. G. G. Antibody ah And notice that um the relative numbers of these antibodies is going to be lower in the primary response in comparison to the numbers and the secondary response over here and so notice that after your body eliminates uh the antigen in the primary response if you are ever encountered with the same specific antigen in the future and a secondary response for example then the time for your body to start producing antibodies is much much shorter, much less than two weeks here in this first period. Uh here it could be less than a week for example and notice that your body is able to start producing the more effective antibody class. The I. G. G. Antibody class uh significantly faster and in significantly higher numbers allowing you to essentially um uh create a more effective immune response the second time that you are exposed to something. And so a lot of times with a secondary response your body is so effective at getting rid of that same antigen that your body may not even develop signs or symptoms because the antigen is eliminated before your body even has a time to generate signs and symptoms. And so basically what we're saying here is that the primary immune response, the very initial exposure to an antigen. Your body will take more time and it will create a less effective immune response. But the second time that you are exposed to the same exact antigen, your body will create antibodies significantly faster and and significantly higher numbers, allowing your body to create a more effective immune response and a secondary exposure. And if we were to have a tertiary exposure then the response would be even better than the secondary response. And that would continue to happen as you are exposed to the same exact antigen. Over time your body gets better and better and better at defending itself. And so this here concludes our brief lesson on the primary and secondary responses of adaptive immunity and how these memory B and T cells are critical for the secondary and all future responses of adaptive immunity. And so we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video
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Problem
ProblemDuring an immune response, the latent or lag period is the number of days between the initial infection of the host and antibody production used to fight the infection. Which type of immune response will have the longer latent period?
A
Primary Immune Response.
B
Secondary Immune Response.
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Problem
ProblemWhich antibody class rises to its highest concentration during a secondary response?
A
IgA.
B
IgE.
C
IgM.
D
IgG.
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Problem
ProblemDoes the graph correspond with a primary or secondary infection?
A
Primary Immune Response.
B
Secondary Immune Response.
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Problem
ProblemPeople that are immune to a certain disease have ________ class antibodies against the disease years later.
A
IgA.
B
IgG.
C
IgM.
D
IgE.
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Problem
ProblemIf you draw a blood sample from a patient to determine whether he or she has a herpes simplex infection, and the patient displays a large amount of IgG against the virus but low levels of IgM, what do you conclude?
A
The patient is newly infected.
B
The patient has had the infection for a while.
C
The patient is not infected.
D
It is impossible to draw conclusions.
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Problem
ProblemPut the following steps in the correct sequence to elicit an antibody response:
(1) TH cell recognizes B cell.
(2) APC contacts antigen.
(3) Antigen fragment displayed on surface of APC.
(4) TH recognizes antigen on APC is immunogenic.
(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.