A novel culture environment for generating mature human dentritic cells from peripheral blood CD14(+) cells

Background: We recently demonstrated that supernatants from cultures of per ipheral blood mononuclear cells (PBMC) activated with anti-CD3-specific ant ibody (ACD3S) can induce upon brief exposure, tumor-reactive lymphocytes in cancer patients. Here, we report that ACD3S can also induce rapid and stab le maturation of dendritic cells (DC) which can be used as antigen presenti ng cells in in vitro protocols and for cancer immunotherapy in vivo. Materi als and methods: A short (4-day) priming of CD14+ monocytes with granulocyt e-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) fo llowed by only a 24 hour-incubation in ACD3S, is sufficient to generate ful ly mature and stable DC. Results: These DC (i) stimulated strong T cell pro liferative responses in the mixed lymphocyte reaction, (ii) when pulsed wit h unfractionated peptides from autologous tumor membrane extracts activated CD4+ T cells which proliferated in response to the autologous tumor and CD 8+ cytotoxic T cells (CTL) which specifically lyse autologous tumor targets and (iii) produced high levels of IL-I2. Conclusion: ACD3S-treated DC are functionally superior to monocyte-conditioned medium (MCM)-treated DC gener ated under the same short-term protocol and as efficient as DC induced by t he standard 10-day protocol. Our data present an efficient and effective me thod for generating, in a very short period of time, highly mature and func tionally competent DC.