BI301 - The Generation of Lymphocyte Antigen Receptors

A developing T cell may by chance express both an αβ heterodimer and a γδ heterodimer if all the loci recombine successfully.

False

Which of the following factors involved in antigen-receptor recombination could be deleted without completing ablating antigen receptor formation?

A. Artemis
B. TdT
C. RAG-2
D. Ku
E. XRCC4

B. TdT

Both B and T cells can undergo somatic hypermutation of their antigen receptor in the context of an immune response in order to enhance antigen affinity.

False

Which of the following is not true concerning the evolutionary history of the adaptive immune system?

A. Adaptive immunity arose abruptly in evolution.
B. Fruitflies and mosquitoes exhibit diversity in the secreted Dscam protein by alternative splicing of a vast array of different exons, while freshwater snails exhibit diversity in FREP genes by differential accumulation of genomic mutations in these genes.
C. Jawless fish recombine VLR genes during DNA replication to engender diversity in these genes, which are expressed on lymphocytes and have GPI-anchored and secreted forms.
D. RAG-1 arose from transposases while the RSSs it recognizes arose from terminal repeats from DNA transposons.
E. MHC class I and class II genes arose before T cells and immunoglobulins in cartilaginous fish.

E. MHC class I and class II genes arose before T cells and immunoglobulins in cartilaginous fish.