Recycled addition of CD4+ T cell-rich population for induction of human autologous cytotoxic T lymphocytes: A practically efficient method.

When CD4(+) T cell-rich population appears in theinitial trial in induction cultures of humanautologous cytotoxic T lymphocytes (CTL), the cultureresults frequently in no or weak killing activity andtherefore usually be discarded as an ;unsuccessful'CTL induction culture. However, addition of theinitial CD4(+) T cell-rich population enabledefficient induction of the autologous CTL in theensuing trials. The CTL thus generated exhibitedstronger killing activities against autologous braintumor cells and ovarian tumor cells than previouslyobserved. This simple recycling of the primed butinert CD4(+) T cell-rich population for CTLinduction will promote clinical practice of adoptiveimmunotherapy of human tumors with autologous CTL.