T cell responses in melanoma patients after vaccination with tumor-mRNA transfected dendritic cells

We have developed an individualized melanoma vaccine based on autologous dendritic cells (DCs) transfected with autologous tumor-mRNA. The vaccine targets the unique spectrum of tumor antigens in each patient and may recruit multiple T cell clones. In a recent phase I/II trial, we demonstrated T cell responses against vaccine antigens in 9/19 patients evaluable by T cell assays. Here, we report a follow-up study that was conducted to characterize interesting T cell responses and to investigate the effects of long-term booster vaccination. Two patients were selected for continued vaccine therapy. The clinical follow-up suggested a favorable clinical development in both patients. The immunological data (T cell proliferation/IFNgamma ELISPOT/Bioplex cytokine assays) indicated sustained T cell responses and suggested an enhancing effect of booster vaccinations. Both CD4(+) and CD8(+) T cell responses were demonstrated. From post-vaccination samples, we generated 39 T cell clones that responded specifically to stimulation by mRNA-transfected DCs and 12 clones that responded to mock-transfected DCs. These data clearly indicate a two-component vaccine response, against transfected and non-transfected antigens. T cell receptor (TCR) clonotype mapping, performed on 11 tDC-specific clones, demonstrated that 10/11 clones had different TCRs. The results thus indicate a broad spectrum T cell response against antigens encoded by the transfected tumor-mRNA. We generally observed mixed Th1/Th2 cytokine profiles, even in T cell clones that were confirmed to be derived from a single cell. This finding suggests that cytokine patterns after cancer vaccination may be more complex than indicated by the classic Th1/Th2 dichotomy.     

The immunological response and post-treatment survival of DC-vaccinated melanoma patients are associated with increased Th1/Th17 and reduced Th3 cytokine responses

Introduction

Immunization with autologous dendritic cells (DCs) loaded with a heat shock-conditioned allogeneic melanoma cell lysate caused lysate-specific delayed type hypersensitivity (DTH) reactions in a number of patients. These responses correlated with a threefold prolonged long-term survival of DTH⁺ with respect to DTH^? unresponsive patients. Herein, we investigated whether the immunological reactions associated with prolonged survival were related to dissimilar cellular and cytokine responses in blood.

Materials and methods

Healthy donors and melanoma patient’s lymphocytes obtained from blood before and after vaccinations and from DTH biopsies were analyzed for T cell population distribution and cytokine release.

Results/discussion

Peripheral blood lymphocytes from melanoma patients have an increased proportion of Th3 (CD4⁺ TGF-β⁺) regulatory T lymphocytes compared with healthy donors. Notably, DTH⁺ patients showed a threefold reduction of Th3 cells compared with DTH^? patients after DCs vaccine treatment. Furthermore, DCs vaccination resulted in a threefold augment of the proportion of IFN-γ releasing Th1 cells and in a twofold increase of the IL-17-producing Th17 population in DTH⁺ with respect to DTH^? patients. Increased Th1 and Th17 cell populations in both blood and DTH-derived tissues suggest that these profiles may be related to a more effective anti-melanoma response.

Conclusions

Our results indicate that increased proinflammatory cytokine profiles are related to detectable immunological responses in vivo (DTH) and to prolonged patient survival. Our study contributes to the understanding of immunological responses produced by DCs vaccines and to the identification of follow-up markers for patient outcome that may allow a closer individual monitoring of patients.     

Functional analysis of tumor-specific Th cell responses detected in melanoma patients after dendritic cell-based immunotherapy

Recently, we have demonstrated that tumor-specific CD4+ Th cell responses can be rapidly induced in advanced melanoma patients by vaccination with peptide-loaded monocyte-derived dendritic cells. Most patients showed a T cell reactivity against a melanoma Ag 3 (MAGE-3) peptide (MAGE-3(243-258)), which has been previously found to be presented by HLA-DP4 molecules. To analyze the functional and specificity profile of this in vivo T cell response in detail, peptide-specific CD4+ T cell clones were established from postvaccination blood samples of two HLA-DP4 patients. These T cell clones recognized not only peptide-loaded stimulator cells but also dendritic cells loaded with a recombinant MAGE-3 protein, demonstrating that these T cells were directed against a naturally processed MAGE-3 epitope. The isolated CD4+ Th cells showed a typical Th1 cytokine profile upon stimulation. From the first patient several CD4+ T cell clones recognizing the antigenic peptide used for vaccination in the context of HLA-DP4 were obtained, whereas we have isolated from the second patient CD4+ T cell clones which were restricted by HLA-DQB1*0604. Analyzing a panel of truncated peptides revealed that the CD4+ T cell clones recognized different core epitopes within the original peptide used for vaccination. Importantly, a DP4-restricted T cell clone was stimulated by dendritic cells loaded with apoptotic or necrotic tumor cells and even directly recognized HLA class II- and MAGE-3-expressing tumor cells. Moreover, these T cells exhibited cytolytic activity involving Fas-Fas ligand interactions. These findings support that vaccination-induced CD4+ Th cells might play an important functional role in antitumor immunity.     

Clinical response after intradermal immature dendritic cell vaccination in metastatic melanoma is associated with immune response to particulate antigen

Metastatic melanoma is poorly responsive to treatment, and immunotherapeutic approaches are potentially beneficial. Predictors of clinical response are needed to identify suitable patients. We sought factors associated with melanoma-specific clinical response following intradermal vaccination with autologous melanoma peptide and particulate hepatitis B antigen (HBsAg)-exposed immature monocyte-derived dendritic cells (MDDC). Nineteen patients with metastatic melanoma received a maximum of 8, 2-weekly vaccinations of DC, exposed to HBsAg in addition to autologous melanoma peptides. A further 3 patients received an otherwise identical vaccine that did not include HBsAg. Patients were assessed 1-2 monthly for safety, disease volume, and cellular responses to HBsAg and melanoma peptide. There was no significant toxicity. Of 19 patients receiving HBsAg-exposed DC, 9 primed or boosted a cellular response to HBsAg, and 10 showed no HBsAg response. HBsAg-specific responses were associated with in vitro T cell responses to melanoma peptides and to phytohemagglutinin (PHA). Zero out of 10 non-HBsAg-responding and 4/9 HBsAg-responding patients achieved objective melanoma-specific clinical responses or disease stabilization - 1 complete and 2 partial responses and 1 case of stable disease ( P=0.018). Development of melanoma-specific cellular immunity and T cell responsiveness to mitogen were greater in the group of patients responding to HBsAg. Therefore stimulation of an immune response to nominal particulate antigen was necessary when presented by melanoma peptide-exposed immature DC, to achieve clinical responses in metastatic melanoma. Since general immune competence may be a determinant of treatment response, it should be assessed in future trials on DC immunotherapy.     

Natural Killer T Cells in Advanced Melanoma Patients Treated with Tremelimumab

A significant barrier to effective immune clearance of cancer is loss of antitumor cytotoxic T cell activity. Antibodies to block pro-apoptotic/downmodulatory signals to T cells are currently being tested. Because invariant natural killer T cells (iNKT) can regulate the balance of Th1/Th2 cellular immune responses, we characterized the frequencies of circulating iNKT cell subsets in 21 patients with melanoma who received the anti-CTLA4 monoclonal antibody tremelimumab alone and 8 patients who received the antibody in combination with MART-1_26–35 peptide-pulsed dendritic cells (MART-1/DC). Blood T cell phenotypes and functionality were characterized by flow cytometry before and after treatment. iNKT cells exhibited the central memory phenotype and showed polyfunctional cytokine production. In the combination treatment group, high frequencies of pro-inflammatory Th1 iNKT CD8⁺ cells correlated with positive clinical responses. These results indicate that iNKT cells play a critical role in regulating effective antitumor T cell activity.     

Vaccination of melanoma patients using dendritic cells loaded with an allogeneic tumor cell lysate

The aim of the present phase I/II study was to evaluate the safety, immune responses and clinical activity of a vaccine based on autologous dendritic cells (DC) loaded with an allogeneic tumor cell lysate in advanced melanoma patients. DC derived from monocytes were generated in serum-free medium containing GM-CSF and IL-13 according to Good Manufacturing Practices. Fifteen patients with metastatic melanoma (stage III or IV) received four subcutaneous, intradermal, and intranodal vaccinations of both DC loaded with tumor cell lysate and DC loaded with hepatitis B surface protein (HBs) and/or tetanus toxoid (TT). No grade 3 or 4 adverse events related to the vaccination were observed. Enhanced immunity to the allogeneic tumor cell lysate and to TAA-derived peptides were documented, as well as immune responses to HBs/TT antigens. Four out of nine patients who received the full treatment survived for more than 20 months. Two patients showed signs of clinical response and received 3 additional doses of vaccine: one patient showed regression of in-transit metastases leading to complete remission. Eighteen months later, the patient was still free of disease. The second patient experienced stabilization of lung metastases for approximately 10 months. Overall, our results show that vaccination with DC loaded with an allogeneic melanoma cell lysate was feasible in large-scale and well-tolerated in this group of advanced melanoma patients. Immune responses to tumor-related antigens documented in some treated patients support further investigations to optimize the vaccine formulation. Margarita Salcedo and Nadège Bercovici both contributed equally to this work     

Increased vaccine-specific T cell frequency after peptide-based vaccination correlates with increased susceptibility to in vitro stimulation but does not lead to tumor regression

Although in vitro sensitization assays have shown increased melanoma Ag (MA)-specific CTL reactivity after vaccination with MA peptides, clinical responses have been uncommon. This paradox questions whether data obtained from the in vitro stimulation and expansion of T cells lead to an overestimation of the immune response to vaccines. Using HLA/peptide tetramer (tHLA), we enumerated MA-specific T cell precursor frequency (TCPF) directly in PBMC from 23 melanoma patients vaccinated with gp100:209-217(210M) (g209-2M) peptide. Vaccine-specific TCPF was higher in postvaccination PBMC from seven of seven patients treated with peptide alone and four of five patients treated with peptide plus IL-12 (range of postvaccination TCPF, 0.2-2.4% and 0.2-2.5%, respectively). The increased TCPF correlated with enhanced susceptibility to in vitro stimulation with the relevant epitope. Paradoxically, no increase in postvaccination TCPF was observed in most patients who had been concomitantly treated with IL-2 (1 of 11 patients; range of postvaccination TCPF, 0.02-1.0%), a combination associated with enhanced rates of tumor regression. The lack of increase in TCPF seen in these patients corresponded to inability to elicit expansion of vaccine-specific T cells in culture. This study shows that a peptide-based vaccine can effectively generate a quantifiable T cell-specific immune response in the PBMC of cancer patients, though such a response does not associate with a clinically evident regression of metastatic melanoma.     

Ex vivo generation of human anti-melanoma autologous cytolytic T cells by dentritic cell/melanoma cell hybridomas

Due to their central role in controlling immunity, dendritic cells are logical targets for priming naive cytotoxic T lymphocytes against tumour cells. In a strictly autologous system, we fused dendritic cells with melanoma cells, both of which were derived from patients with metastatic malignant melanoma. Hybridomas were positive for major histocompatibility complex (MHC) class II, CD40, CD54, CD83, CD86, and the pro-inflammatory cytokine interleukin-12. Autologous T lymphocytes were co-incubated with hybridomas. After 6 days, in-vitro-primed T lymphocytes revealed a strong proliferation activity and released Th-1-associated, but not Th-2-associated, cytokines. Furthermore they showed effective anti-melanoma activity, resulting in death of 70 +/- 9% of autologous melanoma cells. After depletion of CD4+ cells from the mixed population of primed T lymphocytes, the remaining CD8+ cells were able to kill 63+/-8% of autologous melanoma cells. Following depletion of CD8+ cells, however, the cytotoxic capacity of the remaining T lymphocytes caused death in only 32+/-6% of autologous melanoma cells. Blocking of MHC class I, but not class II, molecules on hybridomas impaired T cell proliferation, secretion of Th-1-associated cytokines, as well as the cytotoxic activity of primed T cells. These findings strongly suggest that hybridomas deliver melanoma-associated antigens via MHC class I molecules to T lymphocytes, resulting in the generation of CD8+ cytotoxic T lymphocytes with effective anti-melanoma activity in vitro. The data may serve as a basis for the use of hybridomas in the immunotherapy of malignant melanoma in vivo.     

Patient-derived renal cell carcinoma cells fused with allogeneic dendritic cells elicit anti-tumor activity: in vitro results and clinical responses

Renal cell carcinoma (RCC) has been shown to be susceptible to immunotherapeutic treatment strategies. In the present study, patient-derived tumor cells were fused with allogeneic dendritic cells (DC) to elicit anti-tumor activity against RCC. DC from HLA-A2+ healthy donors were fused with primary RCC cells from ten patients. Phenotype of fusion cells were characterized by flow cytometer and confocal microscopy. In vitro, T cell proliferation, IFN-γ secretion and cytotocic T lymphocytes (CTL) activity elicited by allogeneic DC/RCC fusion cells were assessed. Clinically, ten patients were vaccinated with allogeneic DC/RCC fusion vaccine. The adverse effects and toxicity were observed. The clinical response was evaluated by CT scans. After fusion, the created hybrids expressed both tumor associated antigen and DC-derived molecules and could stimulate the proliferation and IFN-γ secretion of T cells as well as elicit strong CTL activity against RCC cells in vitro. In vivo, no serious adverse effects, toxicity, or signs of autoimmune disease were observed after vaccination therapy. Percentage of T lymphocyte subsets in peripheral blood of patients was increased significantly. One of ten patients exhibited a partial response with regression of lung metastases. Six patients showed stable disease with stabilization of previously progressive disease (follow up 1.5 years). The PR and SD responses, exhibited by 7/10 patients who received the allogeneic DC/RCC fusion vaccine treatment, suggest that this approach is safe and can elicit immunological responses in a significant portion of patients with RCC. J. Zhou and D. Weng contributed equally.     

Single cell analysis reveals that IL-4 receptor/Stat6 signaling is not required for the in vivo or in vitro development of CD4+ lymphocytes with a Th2 cytokine profile

The concept that IL-4 is the primary signal for Th2 lymphocyte differentiation has recently been put in doubt by studies in which the production of Th2-associated cytokines was detected in mice deficient in IL-4 synthesis or IL-4R triggering. In this study, we formally demonstrate by single cell analysis that CD4+ lymphocytes with a classical Th2 phenotype (IL-4+, IL-5+, IFN-gamma-, IL-2-) develop in significant numbers in helminth-infected mice deficient in either IL-4R alpha-chain or Stat6. While an expanded population of Th1 (IL-4-, IL-5-, IFN-gamma+, IL-2+) lymphocytes was observed in the same animals, surprisingly, cells with a mixed Th0 cytokine pattern were rare. The cytokine production phenotypes of the Th1 and Th2 subpopulations generated in infected Stat6-deficient mice were unaffected by in vitro neutralization of endogenous IL-4 or IFN-gamma. Nevertheless, while addition of exogenous rIL-12 resulted in transitory IFN-gamma production by Th2 lymphocytes from both wild-type and Stat6-deficient mice, IL-4 synthesis was preserved in the former, but temporarily ablated in the latter cells. Importantly, IL-4+ IFN-gamma- and IL-4- IFN-gamma+ populations similar to those arising in helminth-infected Stat6-deficient mice could also be generated in vitro by repetitive polyclonal stimulation of CD4+CD62Lhigh lymphocytes from uninfected mice of the same strain. Together, the results of these single cell analysis experiments demonstrate that IL-4R/Stat6 signaling, while influencing the final frequency of Th2 lymphocytes, is not essential for Th2 cell development, and suggest that this pathway has a previously unrecognized function in stabilizing Th2 populations once they have emerged.     

Phase I/II study of treatment with dendritic cell vaccines in patients with disseminated melanoma

Previous studies have suggested that immunotherapy with dendritic cell (DC) vaccines may be effective in treatment of patients with AJCC stage IV melanoma. We examined this treatment in phase I/II studies in 33 patients with good performance status and low volume disease. Nineteen patients received DCs plus autologous lysates and 14 patients DCs plus peptides from the melanoma antigens MAGE-3.A2, tyrosinase, gp100, and MART-1. Keyhole limpet hemocyanin (KLH) was used as a helper protein and influenza peptide was given as a positive control. DCs were produced from adherent cells in blood lymphocytes (monocytic DCs), grown in IL-4 and GM-CSF without a maturation step. The DCs were injected into inguinal lymph nodes at weekly intervals (×4), 2 weeks (×1), and 4-weekly intervals (×2). There were 3 responses (3 partial responses) and 1 mixed response in the 19 patients treated with DCs plus autologous lysates. No responses were seen in the group treated with DCs plus peptides. Stable disease (defined as no progression over a period of 3 months) was seen in 4 patients in group 1 and 5 patients in group 2. Treatment was not associated with significant side effects. We examined whether DTH skin tests or assays of IFN- cytokine production may be useful predictors of clinical responses. Twenty-two of 30 patients had DTH responses to KLH and 12 of 13 patients had DTH responses to the influenza peptide. Five of 15 DTH responses were seen against autologous lysates. This was strongly correlated with clinical responses. Approximately half the patients had responses to MART-1 peptide and a third to the other melanoma peptides. Similarly, cytokine production assays showed responses to influenza in 7 of 13 patients, and approximately one third of patients had responses to the other peptides. No IFN- responses were seen in 5 patients against their autologous lysates. There was no correlation between assays of IFN- production and clinical responses. The present studies suggest that autologous lysates may be more effective than the melanoma peptides used in the study as the source of antigen for DC vaccines. DTH responses to autologous lysates appear useful predictors of clinical responses, but further work is needed to identify other measures associated with clinical responses.Abbreviations DC dendritic cells - DTH delayed hypersensitivity skin tests - KLH keyhole limpet hemocyanin - CTL cytotoxic T lymphocytes     

Transcutaneous anti-influenza vaccination promotes both CD4 and CD8 T cell immune responses in humans

Induction of T cell responses has become one of the major goals in therapeutic vaccination against viral diseases and cancer. The use of the skin as target organ for vaccine has been spurred by recent implication of epithelial dendritic cells in CD8 cell cross-priming and suggests that vaccination via the transcutaneous (TC) route may be relevant in the induction of cellular immune responses. We have previously shown that TC application of nanoparticles, on human skin explants, allows targeting of epidermal dendritic cells, possibly via hair follicles. In this study, we have investigated cellular immune responses against an influenza protein-based vaccine by TC vaccination, compared with i.m. vaccination in humans. In this study on 11 healthy volunteers, we found that a newly developed protocol based on cyanoacrylate skin surface stripping induced a significant increase in IFN-gamma-producing T cells specific for influenza vaccine by ELISPOT assays. Interestingly, TC vaccination induced both effector CD4 and CD8 T cell responses, whereas i.m. injection induced strong effector CD4 in the absence of CD8 T cells, as assessed by intracellular cytokine staining and tetramer analyses. This study proposes new perspectives for the development of vaccination strategies that trigger T cell immune responses in humans.     

Autologous dendritic cell vaccine for estrogen receptor (ER)/progestin receptor (PR) double-negative breast cancer

Purpose

A wealth of preclinical information, as well as a modest amount of clinical information, indicates that dendritic cell vaccines have therapeutic potential. The aim of this work was to assess the immune response, disease progression, and post-treatment survival of ER/PR double-negative stage II/IIIA breast cancer patients vaccinated with autologous dendritic cells pulsed with autologous tumor lysates.

Methods

Dendritic cell (DC) vaccines were generated from CD14+ precursors pulsed with autologous tumor lysates. DCs were matured with defined factors that induced surface marker and cytokine production. Individuals were immunized intradermally four times. Specific delayed type IV hypersensitivity (DTH) reaction, ex vivo cytokine production, and lymphocyte subsets were determined for the evaluation of the therapeutic efficiency. Overall survival and disease progression rates were analyzed using Kaplan–Meier curves and compared with those of contemporaneous patients who were not administered DC vaccines.

Results

There were no unanticipated or serious adverse effects. DC vaccines elicited Th1 cytokine secretion and increased NK cells, CD8+ IFN-γ+ cells but decreased the percentage of CD3+ T cells and CD3+ HLA-DR+ T cells in the peripheral blood. Approximately 58% (18/31) of patients had a DTH-positive reaction. There was no difference in overall survival between the patients with and without DC vaccine. The 3-year progression-free survival was significantly prolonged: 76.9% versus 31.0% (with vs. without DC vaccine, p?Conclusion Our findings strongly suggest that tumor lysate-pulsed DCs provide a standardized and widely applicable source of breast cancer antigens that are very effective in evoking anti-breast cancer immune responses.     

Antigen-independent immune responses after dendritic cell vaccination

The ability of cultured, antigen-loaded dendritic cells (DCs) to induce antigen-specific T cell immunity in vivo has previously been demonstrated and confirmed. Immune monitoring naturally focuses on immunity against vaccine antigens and may thus ignore other effects of DC vaccination. Here we therefore focused on antigen-independent responses induced by DC vaccination of renal cell carcinoma patients. In addition to the anticipated response against the vaccine antigen KLH, vaccination with CD83⁺ monocyte-derived DCs resulted in a strong increase in the ex vivo proliferative and cytokine responses of PBMCs stimulated with LPS or BCG. In addition, LPS strongly enhanced the KLH-induced proliferative and cytokine response of PBMCs. Moreover, proliferative and cytokine responses of PBMCs stimulated with the homeostatic cytokines IL-7 and IL-15 were also clearly enhanced after DC vaccination. In contrast to LPS induced proliferation, which is well known to depend on monocytes, IL-7 induced proliferation was substantially enhanced after monocyte depletion indicating that monocytes limit IL-7 induced lymphocyte expansion. Our data indicate that DC vaccination leads to an increase in the ex vivo responsiveness of patient PBMCs consistent with a DC vaccination induced enhancement of T cell memory. Our findings also suggest that incorporation of bacterial components and homeostatic cytokines into immunotherapy protocols may be useful in order to enhance the efficacy of DC vaccination and that monocytes may limit DC vaccination induced immunity. Supported by a grant to Martin Thurnher from the kompetenzzentrum medizin tirol (kmt), a center of excellence.     

Selective growth, in vitro and in vivo, of individual T cell clones from tumor-infiltrating lymphocytes obtained from patients with melanoma

In recent clinical trials in patients with metastatic melanoma, adoptive transfer of tumor-reactive lymphocytes mediated the regression of metastatic tumor deposits. To better understand the role of individual T cell clones in mediating tumor regression, a 5' RACE technique was used to determine the distribution of TCR beta-chain V region sequences expressed in the transferred cells as well as in tumor samples and circulating lymphocytes from melanoma patients following adoptive cell transfer. We found that dominant T cell clones were present in the in vitro-expanded and transferred tumor-infiltrating lymphocyte samples and certain T cell clones including the dominant T cell clones persisted at relatively high levels in the peripheral blood of the patients that demonstrated clinical responses to adoptive immunotherapy. However, these dominant clones were either undetected or present at a very low level in the resected tumor samples used for tumor-infiltrating lymphocyte generation. These data demonstrated that there was selective growth and survival, both in vitro and in vivo, of individual T cell clones from a relatively small number of T cells in the original tumor samples. These results suggest that the persistent T cell clones played an active role in mediating tumor regression and that 5' RACE analysis may provide an important tool for the analysis of the role of individual T cell clones in mediating tumor regression. A similar analysis may also be useful for monitoring autoimmune responses.     

Repeated administration of cytosine-phosphorothiolated guanine-containing oligonucleotides together with peptide/protein immunization results in enhanced CTL responses with anti-tumor activity

The development of therapeutic anti-cancer vaccines designed to elicit CTL responses with anti-tumor activity has become a reality thanks to the identification of several tumor-associated Ags and their corresponding peptide T cell epitopes. However, peptide-based vaccines, in general, fail to elicit sufficiently strong CTL responses capable of producing therapeutic anti-tumor effects (i.e., prolongation of survival, tumor reduction). Here we report that repeated administration of synthetic oligonucleotides containing foreign cytosine-phosphorothiolated guanine (CpG) motifs increased 10- to 100-fold the CTL response to immunization with various synthetic peptides corresponding to well-known T cell epitopes. Moreover, repeated CpG administration allowed the induction of CTL to soluble protein even in the absence of additional adjuvant. Our results indicate that the potentiating effect of CpG in CTL responses required the participation of Th lymphocytes. Repeated CpG administration resulted in overt splenomegaly and lymphadenopathy with a significant increase in the numbers of CTL precursors and dendritic cells. Protein vaccination in combination with repeated CpG therapy was effective in delaying tumor cell growth and extending survival in mice bearing melanoma tumors. These findings support the contention that repeated administration of CpG-oligonucleotides enhances the effect of peptide and protein vaccines leading to potent anti-tumor responses, presumably through the induction of Th1 and dendritic cells, which are essential for optimal CTL responses. The immunostimulatory properties of CpG motifs may be key in inducing a consistent long term immunity to tumor-associated Ags when using peptides or proteins as T cell-inducing vaccines.     

Pertussis Circulation Has Increased T-Cell Immunity during Childhood More than a Second Acellular Booster Vaccination in Dutch Children 9 Years of Age

Here we report the first evaluation of T-cell responses upon a second acellular pertussis booster vaccination in Dutch children at 9 years of age, 5 years after a preschool booster vaccination. Blood samples of children 9 years of age were studied longitudinally until 1 year after the second aP booster and compared with those after the first aP booster in children 4 and 6 years of age from a cross-sectional study. After stimulation with pertussis-vaccine antigens, Th1, Th2 and Th17 cytokine responses were measured and effector memory cells (CCR7-CD45RA-) were characterized by 8-colour FACS analysis. The second aP booster vaccination at pre-adolescent age in wP primed individuals did increase pertussis-specific Th1 and Th2 cytokine responses. Noticeably, almost all T-cell responses had increased with age and were already high before the booster vaccination at 9 years of age. The enhancement of T-cell immunity during the 5 year following the booster at 4 years of age is probably caused by natural boosting due to the a high circulation of pertussis. However, the incidence of pertussis is high in adolescents and adults who have only received the Dutch wP vaccine during infancy and no booster at 4 years of age. Therefore, an aP booster vaccination at adolescence or later in these populations might improve long-term immunity against pertussis and reduce the transmission to the vulnerable newborns. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN64117538.     

Active specific immunotherapy with hapten-modified autologous melanoma cell vaccine

 We have developed a novel approach to cancer immunotherapy – an autologous whole-cell vaccine modified with the hapten dinitrophenyl (DNP). This approach elicits significant inflammatory responses in metastatic sites and some objective tumor responses. Post-surgical adjuvant immunotherapy with DNP-modified melanoma vaccine in a setting of micrometastatic disease produces significant survival prolongation in stage III melanoma patients. Histologically, the inflammatory responses of the tumor consist of infiltration by lymphocytes, the majority of which are CD8⁺, HLA-DR⁺ T cells. T cells from these lesions tend to have mRNA for interferon γ. T cell receptor analysis suggests that the tumor-infiltrating T cells are clonally expanded. DNP-modified vaccine also induces T cells in the peripheral blood, which respond to DNP-modified autologous cells in a hapten-specific, MHC-restricted manner. Moreover, a T cell line generated from these lymphocytes responded to only a single HPLC fraction of MHC-associated, DNP-modified tumor peptides. Since inflammatory responses in metastases were not consistently associated with dramatic tumor regression, we considered the possibility of immunosuppression at the tumor site. We found that mRNA for the anti-inflammatory cytokine, interleukin-10 (IL-10) is expressed in most metastatic melanoma tissues and subsequently demonstrated that IL-10 protein is produced by melanoma cells. Thus the efficacy of DNP vaccine could be further enhanced by inhibition of IL-10 production or binding. Finally, we expect these results obtained with melanoma to be applicable to other human cancers. Received: 6 August 1996 / Accepted: 20 September 1996     

C-C chemokine receptor 4 expression defines a major subset of circulating nonintestinal memory T cells of both Th1 and Th2 potential

CCR4, a chemokine receptor for macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC), has been implicated as a preferential marker for Th2 lymphocytes. Following in vitro polarization protocols, most Th2 lymphocytes express CCR4 and respond to its ligands TARC and MDC, whereas Th1 lymphocytes express CXC chemokine receptor 3 and CCR5 (but not CCR4). We show in this study that CCR4 is a major receptor for MDC and TARC on T lymphocytes, as anti-CCR4 mAbs significantly inhibit the migration of these cells to MDC and TARC. CCR4 is also highly expressed in most single-positive CD4(+) thymocytes and on a major fraction of blood nonintestinal (alpha(4)beta(7)(-)) memory CD4 lymphocytes, including almost all skin memory CD4(+) cells expressing the cutaneous lymphocyte Ag (CLA), but weakly or not expressed in other subsets in thymus and blood. Interestingly, major fractions of circulating CCR4(+) memory CD4 lymphocytes coexpress the Th1-associated receptors CXC chemokine receptor 3 and CCR5, suggesting a potential problem in using these markers for Th1 vs Th2 lymphocyte cells. Moreover, although production of Th2 cytokines in blood T cells is associated with CCR4(+) CD4 lymphocytes, significant numbers of freshly isolated circulating CCR4(+) memory CD4 lymphocytes (including both CLA(+) and CLA(-) fractions) readily express the Th1 cytokine IFN-gamma after short-term stimulation. Our results are consistent with a role for CCR4 as a major trafficking receptor for systemic memory T cells, and indicate that the patterns and regulation of chemokine receptor expression in vivo are more complex than indicated by current in vitro models of Th1 vs Th2 cell generation.