Optimisation, harmonisation and standardisation of the direct mycobacterial growth inhibition assay using cryopreserved human peripheral blood mononuclear cells by Tanner, R, Smith, SG, Van Meijgaarden, KE, Giannoni, F, Wilkie, M, Gabriele, L, Palma, C, Dockrell, HM, Ottenhoff, THM, McShane, H