Quiz 2 Pathophysiology Bio 323 Name: Please be brief and concise. Points will be
ID: 268008 • Letter: Q
Question
Quiz 2 Pathophysiology Bio 323 Name: Please be brief and concise. Points will be deducted for spelling and grammatical errors. Use the backside for additional space. Q1 wbat is the relationsbip between MHC and HLA? Q2 Janet bad a bad of the Flu. A week later sbe got a sore tbroat. On examination tbe lymph gland on ber neck were swollen and the WBC count was 16.3 (pormal 5.1-9.7). Explain the reason for ber swollen glands and the iocreased WBC count Q3 Tom's grandmotber is diagposed with breast cancer. Her surgeon orders biopsies of several lympb nodes from ber neigbboring parts of the body. Tom wonders wby, since ber breast capcer is localized in tbe breast and not lymph podes. What do you tell bim? Q4 wbat are TSA's (Tumor specifié antigens)? Give rwo examples of such antigens and explain tbeir role in tbe treatment and mapagementExplanation / Answer
Q-1) Ans: MHC or major histocompatibility complex are a group of cell surface protein and can be classified into two types: MHC I & MHC II. All nucleated cells in the body contains MHC I but, MHC II are typically expressed by antigen presenting cells, such as macrophage, dendritic cells, B cells.
Now generally when a pathogen enters the body, these antigen presenting cells engulf those pathogens and breaks them into small peptides called antigens. Then they load these antigens to their cell surface as a marker through the MHC receptor (MHC II). So that cytotoxic T cells or T-helper cell-mediated B cells can recognize and kill it.
Now, HLA or human leukocyte antigen is a gene complex encoding the major histocompatibility complex proteins of humen. HLAs corresponding to MHC class I (A, B, and C) present peptides from inside the cell. For example, if the cell is infected by a virus, the HLA system brings fragments of the virus to the surface of the cell so that the cell can be destroyed by the immune system. These peptides are produced from digested proteins that are broken down in the proteasomes. These particular peptides are small polymers, about 9 amino acids in length. Foreign antigens presented by MHC class I attract killer T-cells (also called CD8 positive or cytotoxic T-cells) that destroy cells. MHC class I proteins associate with ?2-microglobulin.
HLAs corresponding to MHC class II (DP, DM, DOA, DOB, DQ, and DR) present antigens from outside of the cell to T-lymphocytes. These particular antigens stimulate the multiplication of T-helper cells (also called CD4 positive T cells), which in turn stimulate antibody-producing B-cells to produce antibodies to that specific antigen. Self-antigens are suppressed by regulatory T cells. HLAs corresponding to MHC class III encode components of the complement system.
Q-4) Ans: Tumor-specific antigen: As the name suggests, these are the antigens produced by tumor cells and it triggers immunity. Tumor antigens are very helpful as they serve as a tumor marker and acts as a potential candidate in cancer therapy.
Any protein produced in a tumour cell that has an abnormal structure due to mutation can act as a tumor antigen. Such abnormal proteins are produced due to mutation of the concerned gene. Mutation of protooncogenes and tumor suppressors which lead to abnormal protein production are the cause of the tumor and thus such abnormal proteins are called tumor-specific antigens. Examples of tumor-specific antigens include the abnormal products of ras and p53 genes. In contrast, mutation of other genes unrelated to the tumor formation may lead to synthesis of abnormal proteins which are called tumor-associated antigens.
Two examples of tumor-specific antigen are:
a) Epithelial tumor antigen (ETA): found in case of Breast cancerRelated Questions
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