Sure. You can expand T cells against a particular antigen and latter check for TCR chain usage. We expand T cells in vitro by stimulating them with antigen-loaded DC.
Nice! Really, immune response in vitro results to enrichment of clones, specific to particular antigen. This unequivocally can be demonstrated by increase in frequency of anigenspecific clones by limiting dilution method. However, unlikely Jodie had in view so artificial situation.