December 1, 2014
Case Study 3
List the different immunoglobulin types and explain where they are found and what their functions are. IgM – found on B cell surfaces and functions as antigen receptor IgD – also found on B-cell surfaces and functions as antigen receptor IgA – antibodies that are secreted across mucus layer to prevent microbes from penetrating cell bodies IgE – defend body from parasites and binds to allergens to initiate destruction. IgG – funtions in neutralizing, opsonation, compliment activation, antibody dependent cell-mediated cytocity, neonatal immunity, and feedback inhibition of B-cells and found in the blood. Looking over this list, do Daniel’s recurrent lung infections make sense? Why? Yes because he is lacking these antibodies to protect his body from these reoccurring lung infections. What is an antigen?
A foreign object that induces an immune response in the body. What is immunoglobulin isotope switching?
It is a biological mechanism that changes a B-cell’s production of immunoglobulin or antibodies from one class to another. How does the failure of immunological isotope switching explain the lack of IgG, IgA, and IgE in Daniel’s blood? Since IgM and IgD are the most prevalent, there aren’t enough of other antibodies to undergo isotope switching. Is this the only explanation for the lack of IgG, IgA, and IgE in Daniel’s blood? No.
Why do you think the doctor suspected the need for genetic testing? There could be genome defects that is causing something in the immune system no to produce these antibodies or the cells. What is the role of a genetic counselor?
To closely look at Daniels genes and see if this immunodeficiency has been passed down from the parents. Draw out the family pedigree that the counselor is presenting and show how this X-linked genetic disorder has passed through Susan’s family tree.
Why is the genetic counselor suggesting genetic testing for Susan’s sisters?...
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