Clinical Exercise on Immunity

Clinical Exercise #4: Immunity
1 Which of the following statements about T cells is false?
1 Helper T cells release cytokines, while cytotoxic T cells kill the infected cell.
2 Helper T cells are CD4+, while cytotoxic T cells are CD8+.
3 MHC II is a receptor found on most body cells, while MHC I is only found on immune cells.
4 The T cell receptor is found on both CD4+ and CD8+ T cells.
2 Based on what you know about MHC receptors, why do you think an organ transplanted from an incompatible donor to a recipient will be rejected?
If MHC molecules between the donor and the recipient differ, natural killer cells (NK) may classify the donor cells as abnormal and attack them, thus destroying the transplanted organ. Incompatibility between the MHC receptors of the recipient and the donor leads to rejection of the transplanted organ because the cells are recognized as non-self by the immune system.
3 The Rh antigen is found on Rh-positive red blood cells. An Rh-negative female can usually carry an Rh-positive fetus to term without difficulty. However, if she has a second Rh-positive fetus, her body may launch an immune attack that causes hemolytic disease of the newborn. Why do you think the hemolytic disease is only a problem during the second or subsequent pregnancies?
When a Rh-negative female has a Rh-positive fetus, the immune system of the woman produces antibodies against the foreign positive Rh antigen. During this first pregnancy, the female is able to give birth devoid of complications. The antibodies remain activated and ready to attack in case the foreign antigens appear again. Therefore, during subsequent pregnancies, the woman’s immune system records the Rh antigen of the fetus as foreign and attacks it, leading to an abortion.
4 Which of the following is both a phagocyte and an antigen-presenting cell?
5 NK cell
6 eosinophil
7 neutrophil
8 macrophage
5 Which immune cells bind MHC molecules on APCs via CD8 coreceptors on their cell surfaces?
9 TH cells
10 CTLs
mast cells
basophils
6 What “self” pattern is identified by NK cells?
altered self
missing self
normal self
non-self
The NK cells identify and destroy cells that express missing self.
7 The acquired ability to prevent an unnecessary or destructive immune reaction to a harmless foreign particle, such as a food protein, is called ________.
the TH2 response
allergy
immune tolerance
autoimmunity
8 A memory B cell can differentiate upon re-exposure to a pathogen of which cell type?
CTL
naïve B cell
memory T cell
plasma cell
9 The ________ filters foreign particles circulating in the blood.
spleen
lymph nodes
MALT
Lymph
10 Explain the difference between an epitope and an antigen.
An epitope is the part of an antigen that binds an antibody, and is recognized by the immune system of the host. On the other hand, an antigen is a foreign substance that triggers the immune system to produce antibodies to attack it. The epitope is therefore located within the antigen and acts as the binding site for the complementary antibody.
What is a naïve B or T cell?
Naïve B or T cells ...