Key Difference – MHC I vs II
Nyob rau hauv cov ntsiab lus ntawm kev tiv thaiv, Major Histocompatibility Complex (MHC) yog ib qho tseem ceeb molecule thaum lub sij hawm lees paub ntawm antigens (tshuaj txawv teb chaws). Lawv raug suav hais tias yog cov txheej txheem ntawm cov cell ntawm cov proteins uas ua haujlwm los khi nrog txawv teb chaws antigens los nthuav qhia lawv ntawm ob qho ntawm T cell; T pab hlwb (TH) lossis cytotoxic T hlwb (TC) los ntawm T cell receptor. MHC chav kawm I thiab MHC chav kawm II yog encoded los ntawm cov noob muaj nyob rau hauv tib neeg leukocyte antigen (HLA) system. MHC cov molecules tam sim no nyob rau ntawm txhua lub xov tooj ntawm tes pom ib feem ntawm cov protein molecule hu ua epitope. Qhov no tiv thaiv lub hlwb tiv thaiv kab mob los ntawm kev tsom nws cov hlwb thaum lub sij hawm nthuav tawm cov antigens uas tuaj yeem yog tus kheej lossis tsis yog tus kheej antigens. MHC class I molecules nthuav tawm antigens ntawm cov co-receptor molecules hu ua CD8 uas nyob ntawm Tc hlwb, qhov sib txawv, MHC class II molecules nthuav tawm antigens ntawm co-receptor CD4 uas nyob ntawm T Hhlwb. Qhov no yog qhov sib txawv tseem ceeb ntawm MHC Class I thiab MHC chav II.
MHC kuv yog dab tsi?
MHC Class I molecules muaj nyob rau ntawm lub xovtooj ntawm txhua lub cell nucleated thiab yog ib qho ntawm ob chav kawm tseem ceeb ntawm MHC molecules. Cov molecules no tsis tshwm sim hauv cov qe ntshav liab tab sis muaj nyob hauv platelets. MHC Class I molecules ntes cov khoom tawg ntawm cov proteins uas tsis yog tus kheej hauv lub cell. Cov kab mob protein no hu ua antigens. Cov antigens uas tsis yog tus kheej pom los ntawm MHC I molecules yog nyob ntawm Tc hlwb. Tc hlwb muaj coreceptor molecules, CD8. MHC I molecules uas nthuav tawm cov tshuaj antigens ntawm CD8 receptors uas yuav pib ua cov tshuaj tiv thaiv kab mob.
Figure 01: MHC I
Vim cov peptides tam sim no nyob rau hauv MHC Class I molecules yog muab los ntawm cytosolic proteins, txoj kev nthuav qhia antigen ntawm cov molecules yog hu ua endogenous (cytosolic) txoj kev. MHC Class I molecules yog tsim los ntawm ob txoj hlua tsis zoo, cov saw ntev alpha, thiab ib qho luv beta saw. Lawv raug encoded los ntawm tib neeg leukocyte antigen noob (HLA) HLA-A, HLA-B, thiab HLA-C. Alpha saw yog coded ntawm qhov chaw ntawm MHC hauv chromosome 6 thiab beta saw yog encoded ntawm chromosome 15.
MHC Kuv cov molecules ua haujlwm ua tus xa xov hauv kev nthuav tawm cov protein nyob hauv cov cell rau Tc hlwb kom tiv thaiv cov lus teb tiv thaiv kab mob los ntawm tus tswv tsev lub hlwb. Thaum cov proteins intracellular degrade los ntawm cov proteasome, peptide hais khi rau MHC I molecules. Cov peptide particles no hu ua epitopes. MHC Class I protein complex yog nthuav tawm mus rau sab nraud plasma membrane ntawm lub cell ntawm endoplasmic reticulum. Tom qab ntawd, cov epitopes tau khi rau ntawm qhov chaw sab nraud ntawm MHC I molecules. Vim tias cov txheej txheem no, Tc hlwb yuav tsis qhib rau hauv kev teb rau tus kheej-antigens. Qhov no yog hu ua T cell tolerance (Central thiab peripheral kam rau ua). MHC Class I proteins muaj peev xwm nthuav tawm cov tshuaj tiv thaiv exogenous los ntawm ntau yam kab mob. Qhov no yog hu ua cross-presentation. Thaum cov xwm txheej zoo li no, thaum muaj cov tshuaj tiv thaiv txawv teb chaws nthuav tawm ntawm Tc hlwb los ntawm MHC I molecules, cov tshuaj tiv thaiv kab mob yuav pib.
MHC II yog dab tsi?
MHC Class II molecules yog qhia los ntawm hom tshwj xeeb ntawm cov hlwb hu ua antigen presenting cells (APC). APC suav nrog macrophages, B hlwb, thiab dendritic hlwb. Thaum MHC Class II molecule ntsib ib qho antigen, nws yuav siv cov antigen mus rau hauv lub cell, ua nws, thiab ces ib feem ntawm ib tug molecule ntawm antigen (epitope) yog nthuav tawm nyob rau saum npoo ntawm MHC Class II. Cov peptide particles yog muab los ntawm phagocytosis qhov twg cov proteins extracellular yog endocytosed thiab zom los ntawm lysosomes. Cov peptide digested yog loaded rau hauv MHC Class II ua ntej lawv tsiv mus nyob rau saum npoo ntawm tes. Lub epitope nthuav tawm ntawm lub xov tooj ntawm tes tuaj yeem paub thiab khi cov khoom sib txuas ntxiv hu ua paratope. Paratope tuaj yeem yog tus kheej lossis tsis yog nws tus kheej antigen. MHC Class II molecules muaj ob qhov zoo tib yam alpha thiab beta chains, uas yog encoded los ntawm MHC qhov chaw ntawm chromosome 6.
Figure 02: MHC II
Cov molecules no yog encoded los ntawm cov noob HLA-D. MHC Class II molecules nthuav tawm cov tshuaj antigens rau lwm lub hlwb ntawm lub cev tiv thaiv kab mob los pib cov tshuaj tiv thaiv kab mob nrog kev pab los ntawm TH hlwb. TH cov hlwb muaj cov co-receptor hu ua CD4. Nrog rau kev koom tes ntawm CD4 thiab T cell receptor, MHC Class II molecules qhib T cell thiab tsim cov tshuaj tiv thaiv kab mob. Lub luag haujlwm tseem ceeb ntawm MHC Class II molecules yog txhawm rau tshem tawm exogenous antigens nyob rau hauv lub cell.
Qhov Zoo sib xws ntawm MHC I thiab II yog dab tsi?
- Ob lub molecules yog synthesized nyob rau hauv ntxhib endoplasmic reticulum.
- Ob leeg MHC I thiab MHC II yog encoded los ntawm cov noob muaj nyob hauv HLA qhov chaw.
- Ob lub molecules muaj nyob rau saum npoo ntawm APC.
- Qhia cov noob hauv ob lub molecules yog co-dominant.
Qhov txawv ntawm MHC I thiab II yog dab tsi?
MHC II vs MHC II |
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| MHC Kuv yog ib qho ntawm ob chav kawm tseem ceeb ntawm Major Histocompatibility Complex (MHC) molecules thiab pom nyob rau ntawm lub xov tooj ntawm tag nrho cov nucleated hlwb. | MHC II yog ib chav kawm ntawm Major Histocompatibility Complex (MHC) molecules ib txwm pom tsuas yog nyob rau ntawm cov tshuaj tiv thaiv kab mob xws li dendric cells, qee lub hlwb endothelial, thymic epithelial hlwb, thiab B hlwb. |
| qauv | |
| MHC I molecule yog tsim los ntawm ob txoj hlua tsis sib xws; Ntev alpha saw thiab ib qho luv beta saw. | MHC II molecule yog tsim los ntawm alpha thiab beta chains uas zoo ib yam. |
| MHC Kuv pom nyob rau ntawm lub xovtooj ntawm txhua lub cell nucleated. | MHC II muaj nyob rau hauv cov tshuaj tiv thaiv kab mob (APC) uas suav nrog B hlwb, macrophages, thiab dendritic cells. |
| Kev sib tham nrog T cells | |
| MHC Kuv cuam tshuam feem ntau nrog cytotoxic T cells (Tc). | MHC II cuam tshuam nrog T pab hlwb (Th). |
| encoded noob | |
| MHC Kuv yog encoded los ntawm noob HLA-A, HLA-B thiab HLA-C. | MHC II is encoded by HLA-D. |
| Function | |
| MHC Kuv koom nrog hauv kev tshem tawm cov tshuaj tiv thaiv endogenous. | MHC II koom nrog hauv kev tshem tawm ntawm cov tshuaj tiv thaiv exogenous. |
Summary – MHC I vs II
MHC molecules feem ntau yog ob hom, Chav I thiab Chav Kawm II. Lawv raug suav hais tias yog ib txheej ntawm cov cell nto proteins uas ua haujlwm los khi nrog txawv teb chaws antigens uas tau txais los ntawm cov kab mob invading. Tom qab ntawd, MHC molecules nthuav tawm cov antigens ntawm ob hom T cell; T pab hlwb (TH) lossis cytotoxic T hlwb (TC) los ntawm T cell receptor. MHC class I molecules muaj nyob rau ntawm lub cell ntawm tag nrho cov nucleated hlwb thiab MHC Class II molecules muaj nyob rau hauv antigen presenting cells (APC) uas muaj xws li B hlwb, macrophages, thiab dendritic hlwb. Ob lub molecules yog synthesized nyob rau hauv ntxhib endoplasmic reticulum thiab MHC I thiab MHC II yog encoded los ntawm noob nyob rau hauv HLA qhov chaw. Qhov no tuaj yeem piav qhia qhov txawv ntawm MHC I thiab MHC II.
Download the PDF Version of MHC I vs II
Koj tuaj yeem rub tawm PDF version ntawm kab lus no thiab siv nws rau offline hom phiaj raws li daim ntawv ceeb toom. Thov download PDF version ntawm no Qhov txawv Ntawm MHC chav kawm I thiab II
