Indicate the Correct Sequence of Events in the Maturation of B

Multiple Choice

Indicate the correct sequence of events in the maturation of B and T lymphocytes.
1) Immature T cells in thymus and immature B cells in bone marrow undergo rapid mitosis under the influence of specific cytokines
2) Segments of genes that produce lymphocyte receptors are spliced and rearranged to produce almost 10¹⁸ different receptors.
3) Cells failing to produce a functional receptor are eliminated via apoptosis
4) Antigen receptors on immature T and B cells are screened during positive selection so that only useful receptors are generated.
5) After passing positive selection, T and B cells complete maturation process and start their patrol of the body for the presence of pathogens.

A) 1, 2, 3, 4, 5
B) 5, 4, 3, 2, 1
C) 1, 2, 4, 3, 5
D) 1, 4, 3, 2, 5