My dental school immunology professor could learn a thing or 200 from you. Thank you for clarifying this concept (and B cell development) for me after hours of rewatching my professor's lectures!!
I do believe in regards to positive selection that it is not the affinity of self-MHC recognition that determines cell fate, but whether or not the peptide bound to MHC is recognized with better affinity by the TCR and it's co-receptor CD4 or CD8. So, if a peptide is presented by MHC II and the developing thymocyte TCR and CD4 co-receptor recognize this peptide with the right affinity, then it becomes a CD4+ T cell. Correct me if I'm wrong, that's just what I read recently that it's a combination of all these factors and the co-receptor affinity is important in positive selection.
20:00 "Positive selection" takes place through the interaction between DP lymphocytes & self MHC molecules ! I've 2 questions : first , Is it dendritic cells that present both MHC I & MHC II self molecules ? second , Why does CD8 WEAKLY recognizes MHC molecules in +ve selections & self antigens in -ve selection ?
Hi Darshit, thanks for watching! This is something that has been the focus of study for a number of years. When I last looked, it appears that both T cells and B cells engage in allelic exclusion. This is how the "unsuccessful" chromosome avoids expressing an antigen receptor that is different from the "successful chromosome. This way we can be sure that T cells and B cells only have 1 antigen specificity. If you have data that says otherwise I would be very interested in it!
In B cells allelic exclusion takes place AFTER (DJ) gene segment rearrangement of the Ig heavy chain in the EARLY progenitor B cell line i.e : starting from the LATE progenitor B cell line ! In T cells the (DJ) gene segment rearrangement of the beta chain - corresponding to the Ig heavy chain - takes place during the DN2 cell line ! Do we have evidence of allelic exclusion starting from the DN3 cell line ??????
"you will have time to digest this"
Me looking at this video 2 days before the test, having not studied at all: "ha, no"
My dental school immunology professor could learn a thing or 200 from you. Thank you for clarifying this concept (and B cell development) for me after hours of rewatching my professor's lectures!!
I do believe in regards to positive selection that it is not the affinity of self-MHC recognition that determines cell fate, but whether or not the peptide bound to MHC is recognized with better affinity by the TCR and it's co-receptor CD4 or CD8. So, if a peptide is presented by MHC II and the developing thymocyte TCR and CD4 co-receptor recognize this peptide with the right affinity, then it becomes a CD4+ T cell. Correct me if I'm wrong, that's just what I read recently that it's a combination of all these factors and the co-receptor affinity is important in positive selection.
love ur channel! made me genuinely interested in the immune system. (instead of just learning it for class!)
why do i pay 1000$ for a teacher that don't teach and you're free
Exactly
You really are an amazing teacher. Thank you for making these videos.
Thank you SO SO much, you really helped me understand this, you're amazing!!!
20:00 "Positive selection" takes place through the interaction between DP lymphocytes & self MHC molecules ! I've 2 questions : first , Is it dendritic cells that present both MHC I & MHC II self molecules ? second , Why does CD8 WEAKLY recognizes MHC molecules in +ve selections & self antigens in -ve selection ?
Because you want the immune response to the mhc molecule and antigen combination and not too strongly to the MHC itself
Thank you! This was very helpful
you're saving my grade!
Thanks
You made my microbiology exam
It's my pleasure
Can I switch my professor with you lol? Seriously though I learned more from her.
very helpful
Nice video mam,I have 1 doubut
allelic exclusion occur during t-cell development like B cell?
Hi Darshit, thanks for watching! This is something that has been the focus of study for a number of years. When I last looked, it appears that both T cells and B cells engage in allelic exclusion. This is how the "unsuccessful" chromosome avoids expressing an antigen receptor that is different from the "successful chromosome. This way we can be sure that T cells and B cells only have 1 antigen specificity. If you have data that says otherwise I would be very interested in it!
In B cells allelic exclusion takes place AFTER (DJ) gene segment rearrangement of the Ig heavy chain in the EARLY progenitor B cell line i.e : starting from the LATE progenitor B cell line ! In T cells the (DJ) gene segment rearrangement of the beta chain - corresponding to the Ig heavy chain - takes place during the DN2 cell line ! Do we have evidence of allelic exclusion starting from the DN3 cell line ??????
Thank u so much
sorry, is this from janeway? what edition?
Yeah it's Janeway. Get the latest edition
Never even said what b stands for. Fail.
It stands for "baby".....or "bitch" like your mom....😅😅😂 not really