Question

1. What benefit can human stem cells provide to individuals with a genetically determine immunodeficiency? How would the process work? Can individuals receive their own stem cells?

2. Fill in the blanks with the missing information about primary and secondary lymphoid organs:

   The ___________ is the site of T cell development and maturation. The ________ is the site of B cell differentiation and hematopoesis.

   The ___________ are the sites where immune responses are mounted to antigens in the lymph. The _____________ is where immune responses are mounted to antigens in the blood. The ___________ is lymphoid tissue that responds to antigen in the digestive, respiratory, and urogenital systems. Epithelial cells lacking microvilli that transport the antigens to these tissues are known as ________.

3. Describe the structure of the B-cell receptor (BCR). How is the BCR able to trigger a signal transduction pathway when its cytoplasmic tail is only 3 amino acids in length? Outline BCR signal transduction from the point of antigen binding through the NF-κB pathway. What is the result of signal transduction events from the BCR?
4. What is agammaglobulinemia? What enzyme is mutated in these patients and what is this enzyme’s function? What happens to people with this disorder?
5. What is Lck and why is it important? What would happen to a T cell if a mutation were introduced in Lck?
6. Define the following and give an example for each:
   1. cytokine
   2. interleukin
   3. chemokine
   4. chemoattractant

Answer 1

1) Stem Cell therapy refers to the use of stem cells to treat various diseases. In immunodeficiency condition, the body fails to fight against the infections due to the absence of B cells, T cells, and lymphocytes. As a result, the body is prone to various infectious disease. In order to overcome this genetic disorder, stem cell therapy has been employed. Stem cells are pluripotent cells that have the capacity to develop into any type of cells.

Stem cells are fused with pluripotent immune cells. The stem cells are injected into the immunodeficient host. These injected cells develop into immune cells such as B cells, T cells etc which is essential for the immunity. Thus, the immune system develops and making the individual capable to fight against the infectious agent.

Umbilical cord-derived mesenchymal stem cells are the most used cells for stem cell therapy. These cells will not be identified by the host. Therefore, stem cell from the host itself is used for the therapy. This type of therapy is called autologous stem cell therapy.

2) The Thymus is the site for T cell development and maturation. The site for the development and differentiation of B cells is Bone marrow(for adults) and liver (for the fetus).

Secondary Lymphoid organs are the site for the antigen gets mounted in the lymph. Lymphocytes in the blood will get mounted to the antigen. Mucosa-associated lymphoid tissue (MALT) protects the digestive, respiratory, and urogenital system tract from various infectious agents. Epithelial cells lacking microvilli that transport the antigens to these tissues are known as Microfold cells