In vitrodendritic cell-induced T cell responses to B cell chronic lymphocytic leukaemia enhanced by IL-15 and dendritic cell–B-CLL electrofusion hybrids

Abstract

SUMMARYHLA class II-restricted proliferative and cytotoxic T cell (CTL) responses to B cell chronic lymphocytic leukaemia (B-CLL) can be generated using autologous dendritic cells (DCs) pulsed with tumour cell lysate. In this study a number of different approaches were used to optimize further the in vitro system. First, the effects of a variety of maturation agents were studied. The addition of TNF-a , polyriboinosinic polyribocytidylic acid (Poly(I:C)) and LPS to autologous DCs resulted in the emergence of only a small percentage of CD83 + DCs, IFN-a having no demonstrable effect. Only the addition of Poly(I:C) to DCs resulted in modestly increased specific cytotoxicity to B-CLL targets, IFN-a and LPS having no effect. Secondly, T cells were pretreated with IL-15, prior to culturing with lysate-pulsed autologous DCs. A significant increase in T cell activation ( P = 0·038), IFN-g secretion ( P = 0·030) and specific cytotoxicity to B-CLL targets ( P = 0·006) was demonstrated compared to untreated T cells. Thirdly, monocyte derived DCs electrofused with B-CLL B cells were compared with lysate-pulsed DCs. T cells stimulated by fused DCs generated higher levels of specific cytotoxicity to autologous B-CLL B cell targets than those stimulated by lysate pulsed DCs ( P = 0·013). Blocking studies demonstrated inhibition of this cytotoxicity by both anti-CD4 ( P = 0·062) and anti-CD8 monoclonal antibodies ( P = 0·018), suggesting the generation of both HLA class I-and HLA class II-restricted CTL responses. In summary, in vitro B-CLL-specific T cell responses can be enhanced further by preincubating T cells with IL-15 and using autologous fused DC-B-CLL hybrids instead of autologous lysate-pulsed DCs. These preliminary data require confirmation with larger numbers of patients. Such an approach, however, may eventually provide effective immunotherapy for treatment of B-CLL.

Expression of RHAMM/CD168 and other tumor-associated antigens in patients with B-cell chronic lymphocytic leukemia

“…a lectin such as Pokeweed mitogen (PWM), was observed in a mixed lymphocyte reaction after single presensitization. The impaired T-cell reactivity in B-CLL patients might be explained by the influence of CD19 + /CD5 + leukemic cells or T regulatory cells on T-cell function as well as on the DC population (5,51) and might be overcome by specific adjuvants, such as IL-12, IL-15 or sCD40L (52,53). After 2 weeks of presensitization, we observed CD8 + T-cells reactive to PWM, IMP peptide or RHAMM/CD168 peptide in another cohort of B-CLL patients (Figs.…”

In vivoanti-tumor effect of hybrid vaccine of dendritic cells and esophageal carcinoma cells on esophageal carcinoma cell line 109 in mice with severe combined immune defi ciency

“…In this experiment, the fusion vaccine EC109-DC, was made from amalgamation of DC, which was induced by combining cytokine from CD34+ hematopoietic stem cells isolated from the cord blood, and the EC109 by traditional Consequently, it is more effective and practical to fuse vaccine with DC than a single antigen in theory [12][13][14] . Some curative effects of fusion vaccine with DC have been seen in clinic experiments [15][16][17][18][19][20][21][22][23][24][25] .…”

Allogeneic dendritic cells pulsed with tumor lysates or apoptotic bodies as immunotherapy for patients with early-stage B-cell chronic lymphocytic leukemia

“…However, Goddard et al have shown that with the appropriate culture conditions, including additional cytokines, morphologically and functionally normal DCs can be generated from patients with B-CLL. 10,11 CLL-DCs were morphologically and phenotypically immature, lacking the maturation antigen CD83 and the costimulatory molecule CD80 and therefore being unable to induce a significant response in an allogeneic mixed lymphocyte reaction (MLR) with a reduced ability to release IL-12 and driven to a Th2 response. Only weak T-cell responses against unstimulated CLL cells have been observed in autologous MLRs.…”

“…[8][9][10] The stimulation of T cells by tumor cell lysate-pulsed DCs has been demonstrated in vitro in B-CLL. 10,11 We therefore wondered if the application of ex vivogenerated dendritic cells (DCs) pulsed with tumor lysates or apoptotic bodies might help to improve the antileukemic immune response in B-CLL patients.…”