CD4 and neoplasm: This is in accord with our previous observation that the secondary response to the parental B16F10 tumour in mice injected with B16FasL is due to a T helper-dependent Ab response [6]: following depletion of Treg, inoculation of mice with B16F10 cells results in stimulation of CD4+ T cell responses capable of tumour rejection in approximately 70% of vaccinated mice [16].