In your new job with a biotech company, you created a new transgenic mouse strai
ID: 79530 • Letter: I
Question
In your new job with a biotech company, you created a new transgenic mouse strain that you nicknamed “I want a salary increase” (IWASI). IWASI mice constitutively express a transgene encoding a rearranged immunoglobulin heavy chain, whose transcription and translation lead to production of functional B-cell receptors (BCRs) with high affinities for a ubiquitous, murine, cell-surface antigen. In comparison with normal mice, your IWASI mice will very likely display [complete the sentence and assess the resulting statements (7-12) as either factually correct (= true) or incorrect (= false)]:
7. increased numbers of circulating B cells, because they have a growth advantage as a result of not having to rearrange their own immunoglobulin heavy chains.
8. increased apoptosis of bone marrow B cells, because of their autoreactive heavy chain expression.
9. decreased incidence of somatic hypermutation in order to reduce negative effects of autoreactivity of transgenic BCRs.
10. reduced numbers of naïve B cells exiting the bone marrow due to high levels of B-cell death during selection processes.
11. increased B-cell class switching, as a means of replacing the autoreactive heavy chain.
12. increased numbers of positively selected T cells in the thymus as a result of increased T-cell help required for B cells replacing the autoreactive heavy chain.
Explanation / Answer
7. true
8.false
9.true
10.true
11. true
12. false
The production of rearragenged b cells will prpduce more as there will be no constrain to effect it. During this process there are chances that the production of autoreactive heavy chain also increases.