I recommend reading about immunological synapses to better understand how various immune cells (particularly T cells and NK cells) can grab onto antigens and aid B cells in maturing higher affinity BCRs and antibodies, as well as encourage division
en.m.wikipedia.org/wiki/Immunolog…
en.m.wikipedia.org/wiki/Immunolog…
CD8+ “Killer” T cells: jcs.biologists.org/content/129/15…
B cells and CD4+ Th cell mediated antibody formation and B cell activation:
step1.medbullets.com/immunology/105…
step1.medbullets.com/immunology/105…
Immature B cells are almost like CD4+ T cells in their own right. Their antibodies are still fused to the membrane, just like T cell receptors are. That’s how your body can select B cells making the right antibodies, and produce more of them.
nature.com/articles/ni050…
nature.com/articles/ni050…
B cells don’t necessarily need T cells to bind to antigens and activate, though.
quora.com/Can-B-lymphocy…
quora.com/Can-B-lymphocy…
You can best think of T cells as dealing with little pieces of virus or pathogen, while also having the ability to bind to the fully formed pathogen without having sufficient “troop” numbers to kill off all the virus in your blood, for example.
B cells, on the other hand, are benefiting from CD4+ T cells that have already bound to a piece of virus, as well as going around and doing their own binding. They are useful for binding to fully or partially formed viruses that they can actually tag.
NK cells and NKT cells are going around looking for cells that are MHCI-, which are invisible to CD8+ T cells, so they can kill the cells.
Antigen-presenting cells (APCs) either serve singular “chew up and present roles” in the case of professional antigen-presenting cells with MHCII (and CD4+ T cells surveillint MHCII), or technically most cells also present antigens with MHCI as well (for killer CD8+ T cells).
I’ll just leave this here for fun.
When T cells do find a cell to kill, they’re quite brutal!
(Video is of CAR-T cells, genetically engineered to replace their T cell receptors with little antibody fragments tied to signaling domains so they recognize specific pathogenic cells)
(Video is of CAR-T cells, genetically engineered to replace their T cell receptors with little antibody fragments tied to signaling domains so they recognize specific pathogenic cells)
Your lymph nodes (and spleen) are full of B cells and other immune cells!
Antibodies are nice because you can have millions of viruses in your blood, and it’s not reasonable to expect millions of cells to have to go recognize all of them. A single B cell can produce tons of antibody, which can go around and tag all of the viruses for destruction.
As I’ve mentioned before, a big issue with SARS-CoV-2 is that the part of the virus that sticks to its viral receptor, ACE2, is stuck so hard to this receptor that immature B cells and antibodies can’t stick in its place. To make matters worse, ACE2 also exists in soluble form.
Learn more about SARS-CoV-2 specifically:
Corrected figure associated with the post below.
