Question

Please select all correct answers

Which of the following contributes to the tremendous diversity of antigenic peptides that can be presented on MHC molecules within a single individual? Select all correct. The person is likely heterozygous for multiple MHC genes The person has multiple MHC genes The person expresses all of the MHC alleles of all of the MHC genes that they have The person likely has more than two alleles for each MHC gene

Answer 1

ANSWER :-

1. The Major Histocompatibility Factor plays a vital role in presentation of an antigen in the form of a peptide on the surface of nucleated cells which in turn is associated with activation of immune response either mediated through the helper T-cell or cytotoxic T-cell. Individuals are usually heterozygous for the MHC genes. There are three regions associated with the genes on chromosome 6 and two functional gene region encodes for around 6 genes and a possibility of presence of 12 alleles in combination with 2 at each loci. One chromosome is inherited from either parent and thus contributes to the heterogeneity. Hence, option 'A' is an appropriate answer.
2. MHC genes are multiple meaning there are many genes involved together contributing to the expression of the Major Histocompatibity complex. The region 1 is associated with genes A, B and C respectively which gives it the characteristic expression of MHC I molecule specific towards cytotoxic T-cells. The region II is associated with genes DP, DQ and DR and are associated with specificity of interaction with respect to cell signaling mediated by the helper T-cells and hence option 'B' can also be considered as an appropriate answer.
3. There are many alleles associated with a particular gene although different combinations are responsible for forming a different haplotype and hence a combination of two alleles in a diploid individual due to presence of two chromosomes indicates that there would not be expression of all the associated alleles of the genes and hence option 'C' is not an appropriate answer.
4. The last option is technically correct as there are many alleles which are associated with a particular gene of the MHC and the segregation and inheritance of these genes from the parents is responsible for mediating the diversity of binding the antigenic peptides and hence option 'D' can be considered as an appropriate answer.

Option 'A', 'B' and 'D' are the most appropriate answers