TPR ICC bio Passage 14 Q. 3

[Futbol99]

I know this is a long shot as we don't have solutions to these. I had it right, but not sure if I had the right reasoning. Thanks in advance:

3. Which of the following would be the best material to use in an immunization that attempts to stimulate the immune system to create memory B-cells?
A) A cytoplasmic protein
B) A protein used to attach nucleic acid to the inner capsid of encapsulated virus
C) A protein on the membrane of an enveloped virus
D) Injectable forms of IgG that have been shown to recognize specific bacterial protein.

Answer C

I know that if you introduce an enveloped virus with a protein on the membrane, it will bind to antibodies and eventually proliferate Plasma and memory B-cells, which answers the question. However at the time of answering this, I was also looking for an answer that can make these memory B cells without actually an infectious virus entering the body. Is that thought just plain wrong? Would you try to prove all the other choices wrong in context? (other than A, its obvious)

Thankssss

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[pilotjoe]

Option C isn't saying using a virus included in the immunization, just the protein. Options A and B are not best because they are not on the external parts of the cell/virus. Option D is not best because IgG will only bind to specific proteins if they are in the body, thus you would have to be already infected for it to work (not how you want to be immunized, lol). Option C is best because it only uses a noticeable antigen on the outside of a capsulated virus.
Hope this helps!

 

[Czarcasm]

Anytime a pathogen enters our bodies (breaching the first lines of defenses such as skin, mucus membranes, acid of the stomach, etc) our innate system attacks it and tries to eliminate it. If the infectious agent is spreading too fast, the innate system tries to maintain it as best as it can until the adaptive immune system has enough time to build up a stronger defense (plasma and memory cells). Innate is non-specific immunity while Adaptive is specific immunity.

The specificity of the adaptive immunity - that is, the antigens that activate a specific naive B or T cell is predetermined during its development. Part of this developmental process basically 'teaches' these naive cells to distinguish between self and non-self. For this reason, a foreign antigen (whether its an infectious agent like a virus or bacteria which release toxins, or even pollen you inhaled) -- these are the types of things that must be encountered to activate our adaptive immune system.

Choices A and B which either can technically illicit an adaptive immune response after they are processed, digested, and presented by APC's (for example: macrophages) to naive T or B cells. But in either case, even if produced, they are ineffective at targeting these proteins because they are essentially hidden away inside the cell or capsid. Choice D, while it is an effective way of dealing with a pathogen, it only provides (passive) or temporary immunity. The antigen would have to be present for both plasma and memory cells to be activated and eliminate the pathogen either directly (phagocytosis by our innate system) or indirectly (antibodies of our adaptive 'memory' system -- and by other means). This is essentially why we take vaccines for the common flu - to activate our memory B and T cells so that when or if we do encounter the virus, we are ready to attack it quickly.

Remember again that the adaptive response takes time - 2 or even 3 weeks to build up which is not quick enough to deal with certain infections, particularly viral infections that spread quickly.