However, in the absence of an adjuvant-only control beyond 20 dpv, it cannot be confirmed that stimulation of TCRαβ+ and TCRγδ+ T cells was exclusively antigen-specific and their role in protection remains more speculative. Similarly, a CD4+ T cell proliferation was detected in response to both challenge and vaccination, with the difference that T helper cells were already distinctive for vaccinated groups at 20 dpv, and could thus serve as an indicator for subsequent protection.