Question:

Could we use this Varicella zoster virus (VV037) antigen to stimulate VZV-specific CD4+ T-cells in blood from latent or acute infected patients to analyse this specific T-cell response by flow cytometry?

Resolution:

Sounds like a noble experiment. I don't see any major problems other than solubility. If the solubility is limiting, then try cleaving into smaller peptides (maybe using CnBr). The buffer can be changed to a more physiologically compatible one via dialysis or G25 chromatography.