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I had a question on MHC molecules since understanding the fundamental concepts is the basis for transplants, autoimmune disease etc...Ultimately is this the way how it works?
=>There are many different alleles within the class I (aka code for different Alpha-heavy chain with different peptide grooves AND thus the variability peptide presentation; B2-microglobulin is the same) and class II MHC genes (codes for BOTH alpha and beta chains);
=> More specifically, there are three genes at the class I locus (A, B, and C- i.e. HLA-A gene codes for a DIFFERENT alpha chain (than HLA-B gene) and thus different peptide groove and thus DIFFERENT MHC class I overall) AND three genes at the class II locus (DP, DQ, and DR- each one (i.e. HLADP gene = a set of alpha and beta chains (vs. HLADQ) and THUS, a different peptide groove and thus a DIFFERENT MHC class II altogether
=> Inheritance: Since, we inherit one block aka HAPLOTYPE of class I (i.e.-HLA-35, HLA-B27, HLA-C28) and one block aka HAPLOTYPE of class II (i.e. HLDP-34, HLDQ-55, HLDR-66) genes from each parent, therefore, for MAXIMUM variability at our peptide grooves, if we are heterozygous, our cells can express as many as SIX different class I (6 different peptide binding grooves because of 6 different alpha chains) and six different class II proteins (6 different peptide binding grooves because of 6 different sets of alpha/beta chains).
=>There are many different alleles within the class I (aka code for different Alpha-heavy chain with different peptide grooves AND thus the variability peptide presentation; B2-microglobulin is the same) and class II MHC genes (codes for BOTH alpha and beta chains);
=> More specifically, there are three genes at the class I locus (A, B, and C- i.e. HLA-A gene codes for a DIFFERENT alpha chain (than HLA-B gene) and thus different peptide groove and thus DIFFERENT MHC class I overall) AND three genes at the class II locus (DP, DQ, and DR- each one (i.e. HLADP gene = a set of alpha and beta chains (vs. HLADQ) and THUS, a different peptide groove and thus a DIFFERENT MHC class II altogether
=> Inheritance: Since, we inherit one block aka HAPLOTYPE of class I (i.e.-HLA-35, HLA-B27, HLA-C28) and one block aka HAPLOTYPE of class II (i.e. HLDP-34, HLDQ-55, HLDR-66) genes from each parent, therefore, for MAXIMUM variability at our peptide grooves, if we are heterozygous, our cells can express as many as SIX different class I (6 different peptide binding grooves because of 6 different alpha chains) and six different class II proteins (6 different peptide binding grooves because of 6 different sets of alpha/beta chains).
