Question: Question 1 1.1 The First Checkpoint In B-cell Maturation Is The Signaling From The Pre-B-cell Receptor (Pre-BCR) And Occurs Only In B-cells That Have Effectively Re-arranged The Ig Heavy-chain Locus. What Happens To The B Cells That Fail The Recombination Of The Ig Heavy-chain Locus And Do Not Express The Pre-B Cell Receptor On The Surface Of The Cell? …

Question 1

1.1
The first checkpoint in B-cell maturation is the signaling from thepre-B-cell receptor (Pre-BCR) and occurs only in B-cells that haveeffectively re-arranged the Ig heavy-chain locus. What happens tothe B cells that fail the recombination of the Ig heavy-chain locusand do not express the pre-B cell receptor on the surface of thecell?
A. They turn off the recombination of the Ig heavy chain genes onthe second Chromosome
B. They undergo apoptosis
C. They start the recombination of the light chain

1.2
Which of the following statements about CD8 T cell response is NOTcorrect?
A. CD8 + T cell activation is enhanced by costimulation
B. CD8 + effector function is less dependent on costimulation thanCD4 + effector function
C. Activation of CD8 + T cells is dependent on CD4 + T helpercell
D. CD8 + T cell activation is induced by recognition of MHC I bypeptide
E. The number of virus-specific CD8 + T cells can increase by up to10,000-fold
D. They try to re-arrange the receptor, a process calledreceptor-edditing
E. They become anergic

1.3
CD4 + (single positive) T cells are derived from
A. CD4- CD8- (double negative) thymocytes expressing a receptorwith affinity for peptide + MHC I
B. CD4 + CD8 + double positive thymocytes expressing a receptorwith affinity for peptide + MHC II
C. CD8 + single positive thymocytes expressing a receptor withaffinity for peptide + MHC II
D. CD4 + regulatory T cells that receive costimulation in thethymus
E. CD4- CD8- (double negative) thymocytes expressing a receptorwith affinity for peptide + MHC II