Helper T cells recognize the self-nonself complex on ___________ cells, while cytotoxic T cells recognize the complex on ___________ cells.

Question

Accepted Answer

Welcome back. Here's our next problem. It says which of the following cells recognize antigens presented in conjunction with Class two MHC molecules. So this can get a little confusing when we're trying to keep track of um to two different classes of MHC molecules which cells present them which cells recognize them. So let's just recall briefly for more content videos. And I'm going to put up a little chart to help us remember. Yeah, I've put MHC two proteins first since that's what our question is asking about and we'll highlight that to remember it. MHC two proteins is what we're looking for and we're looking for which of the cells recognize the antigens presented in conjunction with them. So MHC two proteins we recall are presented by the immune cells only. Um so they've recognized some sort of antigen, they've cut it up into they've ingested it, they cut it up into pieces and they're presenting a piece of that on their surface. And with the MHC two protein um kind of the little red flag. Hey I've ingested something bad, it's foreign. Come get it. And those immune cells that presented are the antigen presenting cells, dendritic cells, macrophages and B cells and those are recognized by So we're going to highlight that because that's what we're looking for. They are recognized by the helper T cells. So if we're looking for our answer we're gonna go straight to choice A helper T cells that's what recognizes the antigens that are presented along with Class two MHC molecules by those antigen presenting cells? The MHC one proteins will just recall to keep that straight are represented by all nuclear did cells in the body. Um When there's something weird going on inside the cell it's been it's a cancerous cell has been infected by a virus. Um They chopped that up, present a portion of it on their surface and MHC one protein has kind of come here, there's something wrong with me and they are recognized by the sight of toxic t cells which come and destroy that infected cell. So let's just look through our other answer choices with that in mind. So Choice B is psycho toxic T cells but as we discussed they are the ones recognized by that recognize MHC one proteins. So since we're looking for the ones that recognize MHC two proteins, that's the helper T cells. Choice C. Is the B cells. While the B cells we found over here are one of the types of cells that present the antigens in conjunction with MHC two class molecules. Um and we're looking for the molecules that recognize those antigens. So that's why Choice C. Is not correct. And finally we have natural killer cells. Um These are cells that help to destroy um aberrant cells without the stimulation of antigens and very interestingly there there they how they work as they recognize cells that don't have MHC one proteins on them. Um As we discussed MHC one proteins are presented by all new created cells in the body. There's sort of an I. V. System saying this is self these are this is myself as well as that warning system of something going wrong. But some cancers some viruses work by kind of suppressing that MHC one as a way of trying to get around the immune system evade those side. A toxic T cells and natural killer cells are sort of the backup system by destroying cells that don't have that don't display MHC one proteins. So that's their function very interesting but not what we're looking for. So not our answer. So again, which of the following cells recognize antigens presented in conjunction with class two MHC molecules and that's choice. A helper T cells. See you in the next video.

Helper T cells recognize the self-nonself complex on _ cells, while cytotoxic T cells recognize the complex on _ cells.

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Key Concepts

Helper T Cells

Cytotoxic T Cells

Major Histocompatibility Complex (MHC)