CD19 and viral infectious disease: The formation of germinal centers and TfH cells was similar in CD1dflox/flox CD19-Cre− and CD19-Cre+ mice and in CD1dflox/flox Mb1-Cre− and Mb1-Cre+ animals, indicating that CD1d-mediated interactions between B cells and NKT cells are not required for the development of germinal centers during viral infection (Figures 2H–2K).