The non-invasive extraction of this antibody and its easy accessibility within chicken eggs underlies its potential as a widespread prophylactic that does not activate the mammalian complement system. For 10 points each:
[10h] Name this evolutionary ancestor of IgG and IgE, which, unlike the former, does not bind to proteins A or G. Avians produce IgM, IgA, and this antibody that is also dominant in the blood of lungfish and reptiles.
ANSWER: IgY [or immunoglobulin Y]
[10e] Unlike IgG, IgY does not readily bind to mammalian receptors named for this region of antibodies. A truncated form of IgY in ducks lacks this region of antibodies that is contrasted with the antigen-specific Fab region.
ANSWER: Fc [accept Fc receptors; accept fragmentable crystallizable region]
[10m] That incompatibility with mammalian Fc receptors is due to IgY’s lack of this region. IgG and IgA contain this flexible, heavy-chain region that connects the Fc and Fab regions.
ANSWER: hinge region
<Kevin Thomas, Biology>