Why is it important that cell surface markers be similar when transplanting donor tissue into a host?  How do the alleles of the glycosyltransferase (GT) gene control the presence of A and B antigens on the surface of red blood cells?

How does a single MHC protein present many differentpeptides to T cells?

B-cell development in the bone marrow is an inherently wasteful process. Nearly half of the pro-B cells produced will die without progressing to the next stage of development. This massive loss of pro-B cells is due to detrimental DJH rearrangements on both alleles of the immunoglobulin heavy-chain locus. the failure of the pro-B cell to make a complete immunoglobulin heavy-chain protein. the inability of many pro-B cells to proceed with rearranging a V₁ to their rearranged DJH sequence. the failure of many pro-B cells to up-regulate Pax5 and become committed to the B-cell lineage.

Defects in antigen receptor gene rearrangement can result in SCID (severe combined immunodeficiency). Infants with RS-SCID (radiation-sensitive SCID) generally require treatment by bone marrow transplantation from a healthy donor. In this treatment, hematopoietic stem cells from the donor will give rise to normal B and T lymphocytes, thereby restoring normal immune function. However, the bone marrow transplantation treatment does not alter the high incidence of cancer in these patients. Why not?

What is the basic structure of the antibody molecule?

M/C Which statement is the best with respect to how the mouse activates the interferon (INF) pathway with this virus based on the graph below? Infection of mice that are wild type or have the indicated protein or cell deletions 120 100 80 % Survival 40 60 60 20 20 0 0 2 4 T 6 Days after infection wild type RIGI minus Toll receptor minus INF a/ẞ minus CD8 T cell minus INF a/ẞ + CD8 T cell minus 8 10 12 Toll receptors are required for activation of the INF pathway. The INF pathway is activated through recognition of the virus by RIGI. Both Toll receptors and RIGI are required for activation of the INF pathway. Neither Toll receptors or RIGI are likely involved in INF pathway activation.

What is a meaning and significance of the main immunoglobulin isotypes?

What is the role of histocompatibility antigens in humans and where are they located?

How antibodies take advantage between prokaryotic and eukaryotic cells?

MHC polymorphism at individual MHC genes appears to have been strongly selected by evolutionary pressures. In other words, there appears to be selection for maintaining hundreds to thousands of different alleles of each MHC gene in the population. This notion is based on the observation that nucleotide differences between alleles that lead to amino acid substitutions are more frequent than those that are silent substitutions (i.e., not changing the amino acid sequence of the protein). In addition, the positions within the MHC protein where most of the allelic sequence variation occurs are not randomly distributed, but are concentrated in certain regions of the MHC protein. This latter point indicates: That some nucleotide sequences within the MHC genes are hot-spots for mutation That MHC genes are more susceptible to point mutations than to larger nucleotide deletions That MHC allelic polymorphism has been driven by selection for diversity in peptide binding specificity That MHC genes…