14. Which of the following is NOT a required step in B and T lymphocyte development?
(A) Proliferative expansion of precursor cells
(B) Cell surface expression of complete antigen receptor complexes
(C) Positive selection
(D) Activation of precursors by foreign antigens
(E) Pre-antigen receptor expression.
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統計: 尚無統計資料
統計: 尚無統計資料