In vitro dendritic cell-induced T cell responses to B cell chronic lymphocytic leukaemia enhanced by IL-15 and dendritic cell-B-CLL electrofusion hybrids.
HLA 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-alpha, polyriboinosinic polyribocytidylic acid (Poly(I:C)) and LPS to autologous DCs resulted in the emergence of only a small percentage of CD83+ DCs, IFN-alpha having no demonstrable effect. Only the addition of Poly(I:C) to DCs resulted in modestly increased specific cytotoxicity to B-CLL targets, IFN-alpha 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-gamma 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.
Goddard
R V
RV
Plymouth Postgraduate Medical School, Derriford Combined Laboratory, Derriford Hospital, Plymouth, Devon, UK.
Prentice
A G
AG
Copplestone
J A
JA
Kaminski
E R
ER
D001402:B-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines; D002459:Cell Fusion; D003713:Dendritic Cells / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D006825:Hybridomas; D016898:Interferon-alpha / Q000494:pharmacology; D019409:Interleukin-15 / Q000276:immunology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D011119:Polynucleotides / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D019496:Cancer Vaccines; D015395:Histocompatibility Antigens Class I; D016898:Interferon-alpha; D019409:Interleukin-15; D008070:Lipopolysaccharides; D011119:Polynucleotides; D014409:Tumor Necrosis Factor-alpha; C049667:poly(rI).poly(dC)