Hey Aristo, Sorry if its a bit confusing. 1) Basically T cells coming from the thymus are naive CD4+ or Naive CD8 T cells. THey are not Th1 or Th2 or CTL YET. Once they arrive at the spleen or lymph organ somewhere, they can be activated to T helper cells or t killer cells. Naive CD4 will always become some form of T helper, cause it has a CD4 receptor. CD8 cell when activated will become a killer cell or memory. CD4 and CD8 is just used to say what type of receptor it has.
Antigen is first recognized by TCR then CD8 checks for the presence of MHC. T cells can only be activated when APC presents the antigen combined with MHC II complex only.Once the presence of antigen and MHC is checked ,signals are sent to the T-cell nucleus. But.But that is not enough to activate the T cell. Hence CD28 and B7 provided the necessary " CO-Stimulation". Gene produces IL-2,which acts on T cell itself.IL-2 has autocrine activity.This stimulates GENE 2 to produce IL-2 receptors.IL-2 receptors is transported to the cell membrane. IL-2 protein fits into IL-2 receptors and this stimulates genes related to cell cycle to start Mitosis.
2) T reg, etc, of what I know are not formed in the thymus, they can be I guess, if they are presented with an antigen in the thymus. But usually T reg and Th17, etc are activated in lymph nodes. Cause this is where dedritic cell usually bring the antigen to present to the Naive T cells. And from there the T reg can activate the B cells.
It is very complicated but for exam purposes best to remember that all T-cells mature in thymus as Naive T-cell and then they can differentiate into CD4+ and CD8+ according to the APC presented in a secondary lymphoid organ.
Wonderful. I agree with a former comment that the patho texts are not written for being able to critically think. Way too much information. These videos are short, take you thru the processes, and really cement the information. Amazing. I have subscribed and will watch them all. I support your work. What a great tool for those who really want to learn and apply the information. Kae
After a lot of thinking i came up with the same conclusion and then i checked the comment of yours. Thanks a lot for replying!! I will share your videos with my colleagues. P.S I've always been using schemata in my studying so your way is really helpful and similar to mine. Greetings from a Greek
Hey there, Awesome videos! I have an exam today and this helps me to repeat everything! By the way: for the CD4+ Tcell differentiation i think you mean TGFbeta (Transforming growth factor beta) instead of "IGFb" -> Differentiation of Th17 and Treg cells, In B cells inhibition of proliferation and IgA production, In macrophages inhibition of activation and stimulation of angiogenic factors And in Fibroblasts increased collagen synthesis. Keep up the vids ! :)
Excellent video sir, much appreciation for it. One thing that stuck out to me however is @ 7:00 in regards to dendritic cell presenting Ag protein via MHC1. This APC uses MHC2.
All nucleated cells" express MHC 1 , while MHC 2 is exclusive for macrophages and APC's , as these cells are nucleated too , so they will also express mhc 1 .
Thankyou so much this is incredibly helpful, i'm so glad you include the cytokines as this really improves my understanding when i have the full picture :)
B cell requires two signals to become activated: 1) Antigen binding 2) Stimulation by T lymphocyte So, when mature, naïve B cell enters lymph node, it is exposed to antigen and then stimulated by T helper cell before it moves into germinal center to proliferate and differentiate? If so , where did the antigen come from, i.e how was it presented? By a dendritic cell? Was it free floating in the blood?
Hey! This is such a useful resource. May I suggest just taking pictures and then stitching them into a "panaroma". Can be done on photoshop or other free software online. Some android/ios apps on the phones can do this for free as well.
Is it IGF beta or TGF beta that helps the CD4 T Cells upon activation with dendritic cells through MHC-II presentation. If I'm not wrong TGF-B1 in presence of IL-6 and TNF-Alpha helps in the differentiation into TH17 regulatory cells, while TGF-B2 helps in the differentiation into TH17 Killer cells. Please correct me if I'm wrong. Nonetheless, thanks to Armando for posting such wonderfully depicted content with well articulated commentary. We are all so grateful to you for your extraordinary content.
You say the T-FH can activate B-cells... but then at the end you say that's it's just the T-H1 and T-H2. confusing. And you've often called the T killer cell a NK. But it's not the same is it? Must the B-cell be activated before it can enter germinal center?
I had this question too. I think that the voice at @14:03 is wrong. Trust in what is written, that is: the T-cell FH is the one who activates the B-cells. :)
From what I understand, TH1 and TH2 promote activation and proliferation of B cells and TFH cells promote class switching (see videos on germinal centers or B cell activation). The term "T killer cell" usually refers to cytotoxic T cells (expressing CD8). However, natural killer (NK) cells are somewhat similar in the sense that both cells recognize infected/damaged cells and induce apoptosis via perforin and granzymes. They differ in the way they recognize cell damage. Cytotoxic T cells are specific to a particular antigen and only induce apoptosis when they recognize this specific antigen bound to an MHC class I molecule on the surface of an adjacent cell. NK cells react to the lack of MHC class I molecules, as some viruses have the means to inhibit expression of MHC in order to avoid detection by the adaptive immune system (e.g. cytotoxic T cells, antibodies, etc.).
Thanks so much sir for your efforts . you helped me a lot. so please can you do the illustration of NK cells video? it's kind of difficult to understand it here, and thanks again :)
Where can I find the explanation of negative selection? Would it be in this process of interaction of the follicular dendritic cells and the naive t cells?
great videos sir but i have a question. you wrote down that follicular dendritic cells activate Naive CD4 and CD8 but from what I know Follicular DC activate B cells..could you please explain? thank you very much
Excelent video! But at @14:03 you say that Th1 or Th2 will activate the B-cell, but I tought that this would be done by the Tfh (unless this is what you said at @12:12 ). After all: who actualy activates B-cells?
@Amando please help answer as I was also lost at 6:00 min. Dendritic cells are APCs and I suppose they have MHCII receptors on them and MHCI, please help understand
All nucleated cells express MHC 1 receptors, and that includes dendritic cells. But dendritic cells are also APC's so they express MHC II receptors as well. Expressing both means that APC's are able to interact with both CD8+ and CD4+ cells. That's what I think anyways
Can someone please clarify???While explaining the activation of naive CD4 cells by a dendritic cell, is the dendritic cell necessarily a different dendritic cell expressing ICAM and MHC 2 or can it be the same cell activating CD 8 cells too as it can express MHC 1 also since it is nucleated???
Koushik Ramachandra Dendritic cells can activate both Cd8 and Cd4 cells, as they can express both MHC1 and MHC2 molecules (one of the only cells that expresses both)
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Hey Aristo,
Sorry if its a bit confusing.
1) Basically T cells coming from the thymus are naive CD4+ or Naive CD8 T cells. THey are not Th1 or Th2 or CTL YET. Once they arrive at the spleen or lymph organ somewhere, they can be activated to T helper cells or t killer cells.
Naive CD4 will always become some form of T helper, cause it has a CD4 receptor.
CD8 cell when activated will become a killer cell or memory.
CD4 and CD8 is just used to say what type of receptor it has.
its uploaded my friend
Antigen is first recognized by TCR then CD8 checks for the presence of MHC. T cells can only be activated when APC presents the antigen combined with MHC II complex only.Once the presence of antigen and MHC is checked ,signals are sent to the T-cell nucleus. But.But that is not enough to activate the T cell. Hence CD28 and B7 provided the necessary " CO-Stimulation". Gene produces IL-2,which acts on T cell itself.IL-2 has autocrine activity.This stimulates GENE 2 to produce IL-2 receptors.IL-2 receptors is transported to the cell membrane. IL-2 protein fits into IL-2 receptors and this stimulates genes related to cell cycle to start Mitosis.
thanksss
2) T reg, etc, of what I know are not formed in the thymus, they can be I guess, if they are presented with an antigen in the thymus. But usually T reg and Th17, etc are activated in lymph nodes. Cause this is where dedritic cell usually bring the antigen to present to the Naive T cells.
And from there the T reg can activate the B cells.
It is very complicated but for exam purposes best to remember that all T-cells mature in thymus as Naive T-cell and then they can differentiate into CD4+ and CD8+ according to the APC presented in a secondary lymphoid organ.
Thank u very much , very very much .
Your channel is one of the best channels i have subscribed.
Carry on bro
Wonderful.
I agree with a former comment that the patho texts are not written for being able to critically think. Way too much information.
These videos are short, take you thru the processes, and really cement the information.
Amazing. I have subscribed and will watch them all.
I support your work.
What a great tool for those who really want to learn and apply the information.
Kae
After a lot of thinking i came up with the same conclusion and then i checked the comment of yours.
Thanks a lot for replying!!
I will share your videos with my colleagues.
P.S I've always been using schemata in my studying so your way is really helpful and similar to mine.
Greetings from a Greek
Hey there, Awesome videos! I have an exam today and this helps me to repeat everything!
By the way: for the CD4+ Tcell differentiation i think you mean TGFbeta (Transforming growth factor beta) instead of "IGFb"
-> Differentiation of Th17 and Treg cells, In B cells inhibition of proliferation and IgA production,
In macrophages inhibition of activation and stimulation of angiogenic factors
And in Fibroblasts increased collagen synthesis.
Keep up the vids ! :)
I am so grateful for your animated lectures, Armando...
Excellent video sir, much appreciation for it. One thing that stuck out to me however is @ 7:00 in regards to dendritic cell presenting Ag protein via MHC1. This APC uses MHC2.
An APC can express both MHC-1 and MHC-2, thus being able to activate both T-helper cells and cytotoxic T-cells.
All nucleated cells" express MHC 1 , while MHC 2 is exclusive for macrophages and APC's , as these cells are nucleated too , so they will also express mhc 1 .
clear, succinct, highly understandable, highly related
Thankyou so much this is incredibly helpful, i'm so glad you include the cytokines as this really improves my understanding when i have the full picture :)
Thank you. You are a great teacher
B cell requires two signals to become activated:
1) Antigen binding
2) Stimulation by T lymphocyte
So, when mature, naïve B cell enters lymph node, it is exposed to antigen and then stimulated by T helper cell before it moves into germinal center to proliferate and differentiate?
If so , where did the antigen come from, i.e how was it presented? By a dendritic cell? Was it free floating in the blood?
Hey! This is such a useful resource. May I suggest just taking pictures and then stitching them into a "panaroma". Can be done on photoshop or other free software online. Some android/ios apps on the phones can do this for free as well.
Thank You so much for your videos!! I have an exam tomorrow and you have helped my understanding greatly. Hopefully i pass.
Your detailed animations are really helpful, thanks man!
Great explanation. I just love your videos. which video includes the Activation of B cells ??
Hopefully, Its just a massive diagram. I dont think that sort of scanning machine exists.
do you not share the illustrations anymore?
You are AMAZING, Thank you very much
hey,
its the next one so: immunology map number VI
You made easy medical studies through your videos😊
nice explanation of the T-cells
Is it IGF beta or TGF beta that helps the CD4 T Cells upon activation with dendritic cells through MHC-II presentation. If I'm not wrong TGF-B1 in presence of IL-6 and TNF-Alpha helps in the differentiation into TH17 regulatory cells, while TGF-B2 helps in the differentiation into TH17 Killer cells. Please correct me if I'm wrong.
Nonetheless, thanks to Armando for posting such wonderfully depicted content with well articulated commentary. We are all so grateful to you for your extraordinary content.
It 's a piece of art
This presentation of DC To t cell via MHC1-is called cross presentation
Your work is amazing. Thank you so much.
You say the T-FH can activate B-cells... but then at the end you say that's it's just the T-H1 and T-H2. confusing. And you've often called the T killer cell a NK. But it's not the same is it? Must the B-cell be activated before it can enter germinal center?
I had this question too. I think that the voice at @14:03 is wrong. Trust in what is written, that is: the T-cell FH is the one who activates the B-cells. :)
From what I understand, TH1 and TH2 promote activation and proliferation of B cells and TFH cells promote class switching (see videos on germinal centers or B cell activation).
The term "T killer cell" usually refers to cytotoxic T cells (expressing CD8). However, natural killer (NK) cells are somewhat similar in the sense that both cells recognize infected/damaged cells and induce apoptosis via perforin and granzymes. They differ in the way they recognize cell damage. Cytotoxic T cells are specific to a particular antigen and only induce apoptosis when they recognize this specific antigen bound to an MHC class I molecule on the surface of an adjacent cell. NK cells react to the lack of MHC class I molecules, as some viruses have the means to inhibit expression of MHC in order to avoid detection by the adaptive immune system (e.g. cytotoxic T cells, antibodies, etc.).
this is a really important video thanks :)
I tried to...looks terrible
Do mention that Tcells can recognise only Peptide fragments
Your vids are always so helpful; thanks so much for every single one of them. Will you be putting these drawings up somewhere? (e.g., as PDF files)
The cytotoxic t cell should kill the dendritic cell who has presented foreign antigen to it ,right? Then why isn't it happening so? Pls answer..
immunology final tomorrow, thank you for this!
All I can offer is a LIKE , brilliant
Great never seen such a great explanation ...Can u upload viDeo on linkage disequilibrium and polymorphism plz
When will you upload your video about the Activation of the B Cells? We are looking forward to watching it! Your videos are very helpful :)
Think you meant TGF beta for th17 and T regs.
Good videos could make it easier to find correct order though
So in the example of a nail puncturing tissue, who are the very first responders? Neutrophils or complement?
Thanks so much sir for your efforts . you helped me a lot. so please can you do the illustration of NK cells video? it's kind of difficult to understand it here, and thanks again :)
Very good illustrated video, only i think you should talk a bit slower!
In the complex it is a great video
You should regulate the video's speed by clicking on configurations (the 'gear' icon in right-bottom of the video)
i love you. thank you so much
Where can I find the explanation of negative selection? Would it be in this process of interaction of the follicular dendritic cells and the naive t cells?
how about with a paronamic camara, or just with an iphone there are some progrms
great videos sir but i have a question. you wrote down that follicular dendritic cells activate Naive CD4 and CD8 but from what I know Follicular DC activate B cells..could you please explain? thank you very much
how can i get a pdf of this and the humoral immunity?
thanks a lot
thank u
Excelent video! But at @14:03 you say that Th1 or Th2 will activate the B-cell, but I tought that this would be done by the Tfh (unless this is what you said at @12:12 ). After all: who actualy activates B-cells?
Th1(Helper T) activates B-cells and Th2 promotes allergic responses
Super
This is what i use: Hugin photo stitcher
How can dendritic cell present the antigen to cd8 t cell since it has mhc class 2 receptors.
And cd8 binds to class 1 receptors
@Amando please help answer as I was also lost at 6:00 min. Dendritic cells are APCs and I suppose they have MHCII receptors on them and MHCI, please help understand
All nucleated cells express MHC 1 receptors, and that includes dendritic cells. But dendritic cells are also APC's so they express MHC II receptors as well. Expressing both means that APC's are able to interact with both CD8+ and CD4+ cells. That's what I think anyways
@@mysteryman595 thx bro
i love you omg
Can someone please clarify???While explaining the activation of naive CD4 cells by a dendritic cell, is the dendritic cell necessarily a different dendritic cell expressing ICAM and MHC 2 or can it be the same cell activating CD 8 cells too as it can express MHC 1 also since it is nucleated???
Koushik Ramachandra Dendritic cells can activate both Cd8 and Cd4 cells, as they can express both MHC1 and MHC2 molecules (one of the only cells that expresses both)
Chris Needham
Thanks
Not great. Too much of art work is really confusing