V(D)J Recombination and Immune Diversity

The video tutorial explains the adaptive immune system, focusing on T and B cells. It details the V(D)J recombination process, crucial for developing diverse antigen receptors. The tutorial covers the structure and function of immunoglobulins and T cell receptors, emphasizing the role of recombination signal sequences and the 12/23 rule. It describes the function of RAG enzymes in DNA cleavage and repair, highlighting potential errors and their implications for immune function.

What are the two major types of lymphocytes involved in the adaptive immune system?

• Dendritic cells and Basophils

• Macrophages and Neutrophils

• T cells and B cells

• Eosinophils and Monocytes

What is the primary purpose of V(D)J recombination in the immune system?

• To destroy pathogens

• To activate immune cells

• To generate diverse antigen receptors

• To produce antibodies

Which part of the immunoglobulin is encoded by VDJ gene rearrangements?

• Light chain

• Heavy chain

• Variable region

• Constant region

What is the estimated number of possible Ig or TCR molecules?

• 1 million

• 10 million

• 100 million

• 1 billion

What are recombination signal sequences (RSSs) composed of?

• Heptamer and nonamer elements

• Exons and introns

• Codons and anticodons

• Promoters and enhancers

What is the 12/23 rule in V(D)J recombination?

• Recombination occurs between two 12 base pair spacers

• Recombination occurs between one 12 base pair spacer and one 23 base pair spacer

• Recombination occurs between two 23 base pair spacers

• Recombination occurs only in the presence of RAG1 and RAG2

Which enzymes are responsible for initiating DNA cleavage in V(D)J recombination?

• Helicase

• DNA polymerase

• Ligase

• RAG1 and RAG2

What is the main pathway for repairing DNA double-strand breaks during V(D)J recombination?

• Homologous recombination

• Base excision repair

• Non-homologous end-joining (NHEJ)

• Mismatch repair

What happens to the excised signal circle (ECS) during cell division?

• It is lost

• It is repaired

• It is replicated

• It is integrated into the genome

What is the consequence of disruptions in the RAG1 or RAG2 genes?

• Uncontrolled cell division

• Enhanced immune response

• Defective V(D)J recombination

• Increased antibody production