Antibodies That Bind with High Affinity to Some Viral Surface

Multiple Choice

Antibodies that bind with high affinity to some viral surface proteins require heavy chain CDR3 loops of unusual length. Whereas the average human heavy chain CDR3 length is ~15 amino acids, antibodies with V_H CDR3 loops of >30 amino acids are readily detected in the repertoire. These antibody heavy chains with CDR3 lengths of >30 amino acids would likely be missing in individuals lacking:

A) RAG-1 and RAG-2
B) DNA-dependent protein kinase (DNA-PK)
C) The nuclease, Artemis
D) The Ku70:Ku80 complex
E) Terminal deoxy nucleotidyl transferase (TdT)