Michiel C. van Aalderen1, Rene A.W. van Lier2 and Pleun Hombrink2 1Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centre (AUMC), Amsterdam 1105 AZ, The Netherlands 2Adaptive Immunity Laboratory and Landsteiner Laboratory of the AUMC at Sanquin Blood Supply Foundation, Amsterdam 1066 CX, The Netherlands Correspondence: m.c.vanaalderen{at}amsterdamumc.nl