In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

[EX Q]:  MHC tetramers , which constitute a labeled MHC - peptide ligand suitable for binding to the Ag - specific receptor on T cells , provide a novel approach for the detection and characterization of such rare cells .
[EX A]: MHC tetramers

[EX Q]:  Our data demonstrate that , in the context of this macrophage line , E12 induces expression of EBF and together these transcription factors coordinately regulate numerous B lineage - associated genes .
[EX A]: transcription factors

[EX Q]:  OBJECTIVE : T lymphocytes can be activated by soluble factors such as cytokines or through direct cell - cell interactions .
[EX A]:
soluble factors