(Solved): In order to pass the first and second checkpoints in \( \alpha: \beta \) T-cell development, (first ...

In order to pass the first and second checkpoints in \( \alpha: \beta \) T-cell development, (first checkpoint) and (second checkpoint) must be expressed at the surface of the developing thymocyte. However, surface expression alone is insufficient to pass each of these checkpoints. The thymocyte must also receive a signal through the . Once this signal has been received, the thymocyte can continue to the next stage of development. For the first checkpoint, this is becoming a and becoming a for the second checkpoint. mature double-positive thymocyte * the pre-T-cell receptor \( { }^{+} \) CD3-associated ITAMs *