# 03 B Cells

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/B%20cell%20function,%20histology/README.md)..

![](https://i.imgur.com/A2zyFOR.jpg)

## BCR

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/BCR%20components/README.md)..

![](https://i.imgur.com/1fwbEZG.jpg)

* FAB: fragment antigen binding
* FC: constant
* Made of monomer IgM antibody

![](https://i.imgur.com/dyO6NT8.jpg)

* purple: variable regions. Vary from 1 B cell to another
* light chain: 1 constant region; heavy chain 3 constant regions
* variable regions end in nitrogen groups; constant end in carboxyl group
* Connected by disulfide bridges 
* macrophage Fc/protein A binds CH2-CH3 region

### Heavy chain

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/BCR%20made%20how/README.md)..

![](https://i.imgur.com/y2z2gYH.jpg)

## Activation

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/2%20ways%20of%20B%20cell%20activation/README.md)..

![](https://i.imgur.com/oxVfk7C.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/T%20Dependent%20B%20activation%20process/README.md)..

![](https://i.imgur.com/4cfprgr.jpg)

1. B cell crosslinked by antigen
2. Second signal required in addition to crosslinking
3. MHC 2 binds TCR and CD4
4. CD40 binds CD40L: class switching
5. B7 binds CD28: T cytokine secretion

![](https://i.imgur.com/i5b5QLG.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/T%20dependent%20B%20activation%20via%20macrophage%20process/README.md)..

![](https://i.imgur.com/1JjQLH3.jpg)

* macrophage antigen presenting instead

### T Independent

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/T%20independent%20B%20activation%20process.%20Why%20is%20this%20process%20important.%20Comparison%20with%20T%20dependent)..

![](https://i.imgur.com/3akFi8f.jpg)

* so many antigen on surface, B cell activated without T

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/T%20dependent%20vs%20independent%20B%20activation/README.md)..

![](https://i.imgur.com/RrAh4pr.jpg)

### Conjugated Vaccine

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/Conjugated%20vaccine%20why,%20examples/README.md)..

![](https://i.imgur.com/DA4OSvs.jpg)

![](https://i.imgur.com/ACgfNmh.jpg)

## Surface Proteins

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/B%20surface%20proteins,%20functions/README.md)..

![](https://i.imgur.com/lujcvb1.jpg)

* CD21 receptor for complement, receptor for EBV 

## Antibody

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/3%20different%20shapes%20of%20antibodies/README.md)..

![](https://i.imgur.com/RxxJjBn.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/Antibody%203%20functions/README.md)..

![](https://i.imgur.com/gCTQ0p5.jpg)

### Protein A

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/Protein%20A%20bacteria,%20function/README.md)..

![](https://i.imgur.com/lRLA8sB.jpg)

* prevents opsonization:

![](https://i.imgur.com/7sEsfpd.jpg)

### Class Switching

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/B%20class%20switch%20process,%20triggers/README.md)..

![](https://i.imgur.com/KtWItuK.jpg)

* only change Fc portion, not FAB portion

![](https://i.imgur.com/XAy53KN.jpg)

* Cm and Cd closes
* Cm and Cd spliced out; B starts to make Cy (IgG), Ca, Ce

### IgM

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/IgM%20functions,%20good%20for,%20bad%20for,%20complement?%20Cross%20placenta?/README.md)..

![](https://i.imgur.com/pBviPSN.jpg)

* Classical pathway: 2 C1 molecules bind together to Fc of IgM; easy to bind because so many IgM Fc together
* Prevents attachment: very large and clumps on to pathogens
* Weak opsonin: too big; macrophages can't get to Fc

### IgG

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/IgG%20function,%20good%20for,%20placenta?/README.md)..

![](https://i.imgur.com/bXte5WE.jpg)

* macrophages bind to Fc very easily 

![](https://i.imgur.com/X1Hoj3l.jpg)

### IgA

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/IgA%20function,%20monomer%20vs%20dimer%20when,%20complement?%20Why%20are%20they%20good%20for%20mucosal%20infections?/README.md)..

![](https://i.imgur.com/NhdPoTh.jpg)

* secretory component in middle of 2 IgA
* linked by secretory: can't complement 

![](https://i.imgur.com/GRq5CQz.jpg)

![](https://i.imgur.com/e8DEvuP.jpg)

### IgA Protease

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/IgA%20protease%20bacteria/README.md)..

![](https://i.imgur.com/BSs1OgZ.jpg)

### IgE

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/IgE%20binds,%20complement?%20pathogenesis%20for%20allergy/README.md)..

![](https://i.imgur.com/1TGHjRn.jpg)

![](https://i.imgur.com/rRbRPff.jpg)

## Somatic Hypermutation

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/somatic%20hypermutation%20is,%20process,%20when%20does%20it%20happen/README.md)..

![](https://i.imgur.com/11Zxg0l.jpg)

* Happens during proliferation after activation
* Stronger binding will proliferate the most

![](https://i.imgur.com/xNp1VUU.jpg)

## B Cell Fate

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/B%20cell%20fate/README.md)..

![](https://i.imgur.com/lfbpZzH.jpg)

![](https://i.imgur.com/Kbraux3.jpg)

## Development Timeline

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/B%20cell%20development%20timeline%20and%20location/README.md)..

![](https://i.imgur.com/gxWzpI1.jpg)

## Vaccines

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/2%20types%20of%20vaccines/README.md)..

* active
* passive

### Active

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/Active%20vaccines%20function,%20types/README.md)..

![](https://i.imgur.com/o1HPdOJ.jpg)

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/live%20attenuated%20vs%20killed/README.md)..

![](https://i.imgur.com/qFfnmuH.jpg)

* Live attenuated: T cell mediated response
* Killed: antibodies against HA antigens of virus
* Inactivated viral vaccines do not infect host cells and therefore do not enter the MHC class I antigen-processing pathway, which is normally required for the generation of a significant CD8+ cell-mediated immune response.  In contrast, live-attenuated viral vaccines strongly stimulate the MHC class I antigen-processing pathway and can generate cytotoxic CD8+ T lymphocytes that kill infected cells.

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/oral%20vs%20IM%20vaccines/README.md)..

![](https://i.imgur.com/0riB2l8.jpg)

### Passive

[\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Immunology/passive%20vaccines%20are,%20time,%20memory,%20examples/README.md)..

![](https://i.imgur.com/ozbdHnz.jpg)

* give if suspicion for rabies, tetanus: neutralize before infection happens