gigi

I know this isn't the homework help section...but those questions seemed to be a little more basic. So a hexapeptide inhibits the activity of a virus in vitro but not in vivo. Which ones of these would be a reason? 1. The peptide could not be processed by dendritic cells. 2. The peptide was too complex. 3. The hexapeptide failed to activate monocytes, macrophages, and dendritic clls. 4. The peptide was too long. 5. The peptide was insufficiently complex. 6. The induced cytokine response was too weak. 7. The hexapeptide failed to activate NK cells. 8. The peptide was too short. 9. The vaccinations did not work becase T-cell epitopes were absent. I'm thinking 1,3,5,8,and 9 are true reasons. but not sure. any ideas on this?

The DNA for an H chain in a B cell making IgE antibody for Tularemia has the following structure: 5′-5'—V8—D4—J2—Cε—Cα2—3'. How many individual rearrangements were required to go from the embryonic DNA to this B-cell DNA? I know IgM is the embryonic immunoglobin, so the rearrangements occur from that one. But I have no idea how you figure out which arrangements occur because can't there be thousands of possibilities for the IgM? Also I know IgE has an extra component on the H chain but doesn't IgM have an extra one as well or am I just imagining things? My guess was 4 individual rearrangements but I'm definitely not sure if that's correct.