These are the questions that were either submitted to me by email or on the cards from class. This page was last updated on October 19th. I could not find it in the book. The complement fragments C3a, C4a and C5a are called anaphylatoxins because they bind to the surface of mast cells and basophils and cause the cells to degranulate, releasing histamine and other compounds. As you may know, usually anaphylaxis is localized causing hay fever, asthma, allergic eczema, hives, etc.
Systemic anaphylaxis is a shock-like condition that can be fatal.
It is believed that all of the blood cells arise from a pluripotent stem cell, which is present in the bone marrow. You will be responsible for the mechanism of rearrangement at the level that was described in class. I didn't go into the biochemistry of the rearrangements, and you won't be responsible for that. Germ line DNA means DNA that has not undergone any of the deletions that form the active antibody genes. In class I drew V2 joined with J3 as an example, but any V region can join with any J region.