subsequently tdt-positive thymocytes become detectable around 19 to 20 wk , and in such glands the peak of proliferative activity is seen among tdt+ , ccd3+ cells which appear to acquire , in a regular sequence , cytoplasmic beta f1 ( tcr-beta ) , mcd3 , and tcr-alpha beta ( wt31 positivity ) together with the loss of tdt and ki67 positivity .
C0007634
cells
C0010834
cytoplasmic