Induction of anti-tumour lymphocytes in cancer patients after brief exposure to supernatants from cultures of anti-CD3-stimulated allogeneic lymphocytes

Chemotherapy ± cetuximab modulates peripheral immune responses in metastatic colorectal cancer

OBJECTIVE

To identify changes in peripheral immune responses in patients with metastatic colorectal cancer (mCRC) treated with irinotecan/5-fluorouracil/leucovorin (IFL) alone or in combination with cetuximab (C-IFL).

METHODS

Peripheral blood mononuclear cells (PBMCs) collected from healthy donors (n = 20) and patients with mCRC receiving treatment with either IFL (n = 30) or C-IFL (n = 30) were tested for cytokine production upon polyclonal stimulation with anti-CD3 monoclonal antibody, T cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR) and T regulatory cell (Treg) frequency. The respective results were evaluated over two treatment cycles and further assessed in relation to response to treatment.

RESULTS

PBMCs prior to treatment exhibited significantly lower production of IL-2, IFN-γ, IL-12 and IL-18 cytokines and lower auto-MLR responses, whereas Treg frequency, IL-4, IL-10 cytokines were increased compared to healthy donors. During treatment, IL-2, IFN-γ, IL-12, IL-18 and auto-MLR responses increased, while Treg frequency and IL-10 secretion decreased significantly compared to the baseline. Responders to treatment exhibited a significantly higher increase in IL-2, IFN-γ, IL-12 and IL-18 production and auto-MLR responses, and higher decrease in IL-4, IL-10 secretion and Treg frequency. Among all patient subgroups analysed, responders to C-IFL demonstrated significantly higher increase in auto-MLR responses, IL-12 and IL-18 secretion and higher decrease in Treg frequency.

CONCLUSION

The disturbed immune parameters observed in patients with mCRC at presentation can be significantly improved during treatment with IFL and this effect can be potentiated by the addition of cetuximab. Monitoring of the peripheral immune system function could be used as surrogate marker in predicting treatment-related outcome.

Combined treatment with bevacizumab and standard chemotherapy restores abnormal immune parameters in advanced colorectal cancer patients

BACKGROUND

Bevacizumab, a monoclonal antibody (mAb) targeting vascular endothelial growth factor (VEGF), has produced promising results when combined with chemotherapy in the treatment of advanced colorectal cancer (CRC). The aim of the present study was to define the immunological profile of metastatic CRC patients at baseline and following chemotherapy with either irinotecan/5-fluorouracil/leucovorin (IFL) alone or IFL in combination with.bevacizumab (B-IFL).

METHODS

Peripheral blood mononuclear cells (PBMCs) obtained from healthy donors (HD) (n = 20) and patients (n = 40) were tested for T-cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR), and cytokine production following stimulation with anti-CD3 mAb.

RESULTS

PBMCs obtained from CRC patients prior to treatment exhibited lower auto-MLR responses and low production of IL-2, IFN-γ, IL-12 and IL-18 cytokines, whereas IL-4 and IL-10 cytokines were increased as compared to HD (p < 0.001, for all parameters) following in vitro stimulation with anti-CD3 mAb. During treatment, and in particular in week 12 of evaluation, IL-2 (p < 0.001 for both IFL and B-IFL groups), IFN-γ (p < 0.001 for IFL and p = 0.001 for B-IFL), IL-12 (p < 0.001 for both IFL and B-IFL) and IL-18 (p < 0.001 for both IFL and B-IFL) production, as well as auto-MLR responses increased (p < 0.001 for both IFL and B-IFL), whereas IL-4 (p < 0.001 for IFL and p = 0.001 for B-IFL) and IL-10 [p < 0.001 for IFL and p = 0.067 (non-significant) for B-IFL] production decreased over baseline in the two treatment groups, yet their respective values never reached those of HD. Moreover, IL-2, IFN-γ production, and auto-MLR were higher in the B-IFL over the IFL treatment group (p < 0.001, p < 0.04, p < 0.001, respectively).

CONCLUSION

Our study demonstrates that the abnormal immune parameters observed in metastatic CRC patients at presentation can substantially improve during treatment with either IFL or B-IFL. The immune parameters examined can provide a sensitive and valuable tool for monitoring immune function in CRC patients, and could be applied as surrogate markers predicting treatment-related outcome.

Products of anti-CD3/anti-CD28 activated lymphocytes induce differentiation and maturation of dendritic cells and have adjuvant-like activity in vitro and in vivo

Dendritic cells (DC) orchestrate immune responses under direction of cytokines/chemokines in their microenvironment. To investigate the influence of that generated during T cell activation, we stimulated peripheral blood mononuclear cells (PBMC) with anti-CD3 and anti-CD28 coated beads and tested cell-free culture supernatants (lymphocyte conditioned medium, LCM) for cytokine/chemokine composition and biologic activity. LCM contained a battery of mediators important in the biology of myeloid (mDC) and plasmacytoid (pDC) DC. LCM differentiated monocytes into functional immature mDC, and induced maturation of immature mDC. LCM also augmented maturation and IFNalpha-production of CpG-treated pDC. Functional activity of LCM-derived DC was confirmed by their ability to enhance in vitro recall T cell responses and substantially augment in vivo cellular and humoral immune responses to various vaccines in non-human primates. These results demonstrate that products of anti-CD3/anti-CD28 stimulated PBMC generate biologically active DC in vitro and function as a vaccine adjuvant in vivo.

Tumor-specific CD4+ T lymphocytes from cancer patients are required for optimal induction of cytotoxic T cells against the autologous tumor

This study focuses on the specific CD4+ T cell requirement for optimal induction of cytotoxicity against MHC class II negative autologous tumors (AuTu) collected from patients with various types of cancer at advanced stages. CD4+ T cells were induced in cultures of cancer patients' malignant effusion-associated mononuclear cells with irradiated AuTu (mixed lymphocyte tumor cultures (MLTC)) in the presence of recombinant IL-2 and recombinant IL-7. Tumor-specific CD4+ T cells did not directly recognize the AuTu cells, but there was an MHC class II-restricted cross-priming by autologous dendritic cells (DCs), used as APC. CD8+ CTL, also induced during the MLTC, lysed specifically AuTu cells or DCs pulsed with AuTu peptide extracts (acid wash extracts (AWE)) in an MHC class I-restricted manner. Removal of CD4+ T cells or DCs from the MLTC drastically reduced the CD8+ CTL-mediated cytotoxic response against the AuTu. AWE-pulsed DCs preincubated with autologous CD4+ T cells were able, in the absence of CD4+ T cells, to stimulate CD8+ T cells to lyse autologous tumor targets. Such activated CD8+ T cells produced IL-2, IFN-gamma, TNF-alpha, and GM-CSF. The process of the activation of AWE-pulsed DCs by CD4+ T cells could be inhibited with anti-CD40 ligand mAb. Moreover, the role of CD4+ T cells in activating AWE-pulsed DCs was undertaken by anti-CD40 mAb. Our data demonstrate for the first time in patients with metastatic cancer the essential role of CD4+ Th cell-activated DCs for optimal CD8+ T cell-mediated killing of autologous tumors and provide the basis for the design of novel protocols in cellular adoptive immunotherapy of cancer, utilizing synthetic peptides capable of inducing T cell help in vivo.