Question: Why are more reads expressed/mapped for human TRB than TRA?
Answer: When viewing results from the Chromium V(D)J Application in Loupe V(D)J Browser, there are both biological and technical reasons why different levels of human T-cell receptor alpha (TRA) vs T-cell receptor beta (TRB) transcripts may be detected within a single cell.
- Biological: TRA transcripts are generally expressed at a lower level than TRB transcripts, although this is cell-type dependent. For example, anti-EBV specific T cells from a healthy donor have higher levels of TRA expression than TRB expression.
- Technical: TRA transcripts are longer than TRB, and thus the assembly of TRA may be more difficult, limiting the ability to detect TRA in single cells.