Augmenting antibody response to EGF-depleting immunotherapy: Findings from a phase I trial of CIMAvax-EGF in combination with nivolumab in advanced stage NSCLC

Background

CIMAvax-EGF is an epidermal growth factor (EGF)-depleting immunotherapy which has shown survival benefit as a switch maintenance treatment after platinum-based chemotherapy in advanced non-small cell lung cancer (NSCLC). The primary objective of this trial is to establish the safety and recommended phase II dose (RP2D) of CIMAvax-EGF in combination with nivolumab as second-line therapy for NSCLC.

Methods

Patients with immune checkpoint inhibitor-naive metastatic NSCLC were enrolled using a “3+3” dose-escalation design. Toxicities were graded according to CTCAE V4.03. Thirteen patients (one unevaluable), the majority with PD-L1 0%, were enrolled into two dose levels of CIMAvax-EGF.

Findings

The combination was determined to be safe and tolerable. The recommended phase 2 dose of CIMAvax-EGF was 2.4 mg. Humoral response to CIMAvax-EGF was achieved earlier and in a greater number of patients with the combination compared to historical control. Four out of 12 evaluable patients had an objective response.

Seq-ing the source of radiation-induced anti-tumor immunogenicity in patient tumors

Translational studies in a small number of patients have demonstrated a clinical benefit when combining radiation and immunotherapy. These findings are supported by correlative data showing that transcriptional changes to the tumor microenvironment following radiotherapy are associated with responses. Yet, given limited access to patient specimens following treatment, few studies have addressed how radiation primes anti-tumor immunity at single cell resolution, thus limiting our understanding of the source of radiation-induced changes within tumors. Here, we acquired renal cell carcinoma (RCC) tumors from patients treated with stereotactic body radiation therapy (SBRT) followed by nephrectomy in a pilot study (NCT01892930), to evaluate radiation-induced transcriptional changes to immune and RCC cells by single-cell RNA sequencing. We hypothesized that SBRT-induced interferon (IFN) and immune-activating signals, previously detected by bulk sequencing and array platforms, would localize to the dense lymphocyte infiltrate characterized in RCC and that the transcriptional signatures in SBRT-treated RCC would reflect increased immune recognition. Single-cell transcriptomics uncovered increased frequency of mature T cells in irradiated tumors, including increased expression of IFN-gamma and granzymes, as well as PD1 and other exhaustion markers. Additionally, irradiated-RCC cells expressed more IFN-gamma receptor and were enriched for IFN signaling and antigen processing pathways. Collectively, these results indicate radiation may improve anti-tumor immunity by increasing both T cell activity and tumor cell sensitivity to pro-inflammatory cytokines and cytolysis in human malignancies.

Abstract PO-038: Hide and Seq: Radiation-induced immunogenicity of patient tumors revealed by single cell analysis

Robust preclinical investigations into radiation-induced immunogenicity has led to increased enthusiasm for combining radiation with immunotherapy. Promising results in a limited number of patients treated with radiotherapy and immune-activating strategies has supported the initiation of over 150 ongoing clinical trials. Yet, due to reduced availability of patient samples following treatment, tumor tissue in particular, there has been sparse investigation of the impact of radiation on immunogenicity in human malignancies. While murine models have revealed important insights into understanding radiation-induced immunogenic mechanisms, inherent differences in radiation sensitivity between mice and humans limit translation to patients. To determine the impact of radiation on patient tumor cells we analyzed samples from renal cell carcinoma (RCC) patients treated with stereotactic body radiation therapy (SBRT) in a pilot study (NCT01892930). Previous data showed radiation induced surface presentation of tumor-associated antigens in resected irradiated tumors. Bulk transcriptomic data of in situ-irradiated tumors showed evidence of immune activation, including increased interferon-gamma (IFNG) signaling, as well as increased T cell clonality and higher abundance of T cells clones with similar binding affinities predicted by dominant motif analysis. We hypothesized that the tumor response to in situ irradiation included increased transcript abundance for tumor antigen genes and antigen-presentation machinery, as well as a response to IFNG signaling. Tumor cell comparisons following single-cell RNA sequencing uncovered RCC cell-specific responses to in situ irradiation. Irradiated RCC tumor cells expressed higher levels of genes encoding MUC-1 and carbonic anhydrase 9, as well as higher expression of calreticulin and genes encoding MHC class 1 molecules: HLA-A, HLA-B, and HLA-C; furthermore, gene set enrichment identified enhancement of antigen processing and presentation pathways. Additionally, irradiated tumor cells expressed higher levels of the IFNG receptor, its downstream targets, and the enrichment of several interferon response gene sets. Collectively, these results indicate radiation may improve tumor recognition through both increased antigen expression and surface presentation as well as sensitize tumor cells to immunogenic cytokines and T cell-mediated cytolysis in human malignancies, such as RCC.

Citation Format: Jacky L. Chow, Nicholas Hoffend, Madeline Gaudieri, Scott Abrams, Thomas Schwaab, Anurag Singh, Jason Muhitch. Hide and Seq: Radiation-induced immunogenicity of patient tumors revealed by single cell analysis [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-038.

Abstract CT130: Evidence for synergistic immune responses in the first-in-human (FIH) combination of B cell-activating immunotherapy (IO) with anti-PD1 immune checkpoint inhibitor nivolumab (N) as 2nd-line therapy in patients (pts) with advanced non-small cell lung cancer (aNSCLC)

Introduction: While combined immunotherapeutic activation of B and T cells is predicted to synergistically enhance both humoral and cell-mediated immunity, this has not been previously tested in human cancer patients. To assess this, we conducted the FIH trial combining B cell-activating IO (CIMAvax-EGF (C)) with T cell-activating IO (PD-1 blockade with nivolumab (N)). C activates B cells to produce endogenous anti-epidermal growth factor (EGF) antibodies (Abs) that deplete EGF from circulation. As a single agent maintenance therapy in aNSCLC, C prolonged overall survival (OS) in a randomized phase III trial. We now present immune correlates of improved OS with this novel combination. Methods: We reported safety and preliminary efficacy data from 13 pts from the phase I study of C+N (AACR 2019). Serial blood samples were analyzed by Luminex for dynamic changes in circulating cytokines and proteins implicated in EGF signaling, and by flow cytometry for peripheral blood mononuclear cell immunophenotype. Cox regression analysis was used to analyze association with OS. Results: 71% of pts achieved anti-EGF Ab titers of >1:4000 after 3 doses of C, compared to historical controls of 39% with C alone. Baseline increase in CD8+ naive T cells, memory B cells, and decrease in MDSC and Th17 T cells all significantly correlated with better OS. Baseline increase of inflammatory cytokines/markers (IL7, IL15, IFNα, IL8, sCD40L and CRP) significantly correlated with worse OS. Despite enrichment for pts with tumor proportion score (TPS) PD-L1 0%, median OS (mOS) of the intent-to-treat population (pts who received at least 1 dose of C+N, n=13) was 13.7 months (mo) vs. 9.9 mo in Checkmate 057 aNSCLC pts with tumor proportion score (TPS) PD-L1 <10%. mOS of per-protocol pts (all 4 loading doses of C+N given over 8 weeks, n=11) was 18.5 mo. In contrast to Checkmate 057 results, where OS benefit of N favored aNSCLC with KRAS mutation (KRASm), C+N showed better mOS of 22.4 mo in EGFR/ALK/KRAS wildtype (wt) pts versus 12.3 mo in KRASm/STKwt pts. Conclusion: This study provides evidence for synergistic effects of combining B and T cell activating IO in aNSCLC pts. C+N generated higher anti-EGF titers in more pts at an earlier time point vs. C alone, which is the first demonstration in pts of enhancement of Ab responses by immune checkpoint blockade. Immune analysis identified new specific immune cell populations and inflammatory markers that significantly correlate with OS with C+N that have not been previously identified with C or N as single agents. C+N improved OS compared to historical controls of aNSCLC pts receiving N in phase III trials. Of particular note, C+N showed better OS in pts with EGFR/ALK/KRAS wt aNSCLC versus KRASm/STKwt pts. The Phase II portion of the study is ongoing.

Citation Format: Tania Crombet, Jason Muhitch, Circe Mesa, Rachel Evans, Danay S. Hernandez, Patricia L. Luaces, Zaima Mazorra, Orestes Morales, Carlos Cedeno, Aileen Cinquino, Daniel T. Fisher, Kelvin Lee, Mary Reid, Grace Dy. Evidence for synergistic immune responses in the first-in-human (FIH) combination of B cell-activating immunotherapy (IO) with anti-PD1 immune checkpoint inhibitor nivolumab (N) as 2nd-line therapy in patients (pts) with advanced non-small cell lung cancer (aNSCLC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT130.

Initial correlative studies from a trial of cetuximab and pembrolizumab in metastatic colorectal cancer (mCRC)

4062

Background: Cetuximab is an EGFR-targeting IgG1 mAb. Pre-clinical data suggests cetuximab induces CD8+ cytotoxic T-cell (CTL) infiltration of tumors. We hypothesized that augmentation of CTLs in the tumor microenvironment (TME) may provide the proper milieu for effective PD-1 inhibition in metastatic colorectal cancer (mCRC). We conducted a phase Ib/II study of cetuximab with the PD-1 antibody, pembrolizumab, in mCRC. Correlative blood and tissue samples were collected to assess the impact of this treatment on CTLs, as well as potential compensatory alterations in regulatory T-cells (Tregs) and suppressive MDSCs (NCT02713373). Methods: 3 week treatment cycles included pembrolizumab at 200 mg on day 1 and cetuximab 250 mg/m2 following the 400 mg/m2 loading dose. Tumor biopsies were obtained at baseline and at c4d1 (Day 64). Peripheral blood (PB) was drawn at baseline, c2d1 (day 22) and c4d1 (Day 64). Flow cytometry was performed within 24 hours with additional samples stored for future analysis. In the present analysis, we assessed changes in levels of the cellular populations of interest between cycle 4 and cycle 1. Results: Forty-two RAS-wt patients were enrolled through October 2019. Paired tumor tissues were successfully analyzed for 16 patients and PB for 38. Intratumoral CTLs (CD3+CD8+) increased significantly (+47%, p < .05). In PB, there was a slight overall decrease in PB CTLs (-5%, p = NS) and a significant decrease in CD8+CD45RO+PD1+ cells (-42%, p < .05). We saw simultaneous decreases in PD-1+ CTLs in the tumor and PB. There was a trend for increase in Tregs (CD4+ Cd25+ FoxP3+) in PB (+11%, p = NS), but an overall increase in the Teff:Treg ratio (+30%, p = NS). CD4+CTLA4+ cells significantly increased (+37%, p < .05). Granulocytic MDSCs (CD11b+CD14−CD33+HLADR−) in PB decreased significantly on-treatment (-30%, p < 0.5). The sample size and tissue limitations prohibited meaningful evaluation of tissue Tregs and MDSCs via the present methods. Conclusions: Cetuximab and pembrolizumab induced dynamic changes in the TME and PB. The treatment associated increase in intratumoral CTLs was particularly pronounced, consistent with their local expansion and/or influx. This was accompanied by a decrease in PB CTLs. Decreases in multiple PD-1+ lymphoid populations were observed in both tumor and PB, notably PD-1+ CTLs. Of note, we saw a synchronous increase in immunosuppressive CD4+CTLA4+ T-cells in PB. Patient outcomes are pending maturation. Further analyses are planned, coupled with integration of clinical data. Clinical trial information: NCT02713373 .

Interim analysis of a pilot study: Impact of high-dose, single fraction radiation on immunogenicity of sipuleucel-T in metastatic castration resistant prostate cancer patients

e16538

Background: Sipuleucel-T is known to have modest anti-tumor activity in pts with metastatic castration resistant prostate cancer (mCRPC). Synergy of radiotherapy and immunotherapy has been reported. We conducted a pilot study to assess the impact of radiation on immunogenicity of Sipuleucel-T. Methods: Pts with minimally symptomatic mCRPC and bone metastases were eligible. Pts received Sipuleucel-T every 2 wks x 3 infusions. 8 Gy RT to 1 bone lesion was given 2 days after the first infusion. Peripheral blood was collected at D0, 7d after each infusion, 3 and 6 m. Primary endpoint is the effect of RT on immunogenicity of Sipuleucel-T. Secondary endpoints were safety, PSA changes and survival. We will evaluate T cell proliferation and cytolytic response at baseline and post-treatment using thymidine incorporation assay, IFN-y ELISPOT and flow cytometry. Results: From 10/2013 to 7/2018, a total of 15 pts were enrolled. Median age was 69 years (59-77). 10 pts (67%) had GS > = 8 disease. 7 pts (47%) failed prior abiraterone or enzalutamide. 13 pts completed treatment per protocol (2 withdrew). During a median follow-up of 48 mos, the 3-year overall survival was 48% (95% CI, 21-71); median survival was 30.7 mos (95% CI, 14.6-NR). No PSA responses were observed. 11 pts had post-treatment imaging (non-mandatory). 10 had PD and 1 had SD. 10 pts (67%) had Grade 1-2 drug-related AEs (most common: dizziness and hematoma 20%). No DLT or grade 3-5 drug-related AEs were observed. Conclusions: Sipuleucel-T plus RT is well tolerated. Median overall survival in this limited subset of pts was encouraging, when compared with historical data (25.8 mos in IMPACT trial). The evaluation of immune response is ongoing. (Funded by DENDREON; ClinicalTrials.gov ID: NCT01833208) Clinical trial information: NCT01833208.

Total cellular protein presence of the transcription factor IRF8 does not necessarily correlate with its nuclear presence

The transcription factor interferon regulatory factor-8 (IRF8) plays an essential role in myeloid differentiation and lineage commitment, based largely on molecular and genetic studies. The detection of IRF8 in specific cell populations by flow cytometry (FCM) has the potential to provide new insights into normal and pathologic myelopoiesis, but critical validation of this protein-based approach, particularly in human samples, is lacking. In this study, the assessment of total cellular IRF8 presence was compared to its specific nuclear presence as assessed by imaging flow cytometry (IFC) analysis. Peptide neutralization of the IRF8-specific antibody that has been predominantly used to date in the literature served as a negative control for the immunofluorescent labeling. Expression of total IRF8 was analyzed by total cellular fluorescence analogous to the mean fluorescence intensity readout of conventional FCM. Additionally, specific nuclear fluorescence and the similarity score between the nuclear image (DAPI) and the corresponding IRF8 image for each cell were analyzed as parameters for nuclear localization of IRF8. IFC showed that peptide blocking eliminated binding of the IRF8 antibody in the nucleus. It also reduced cytoplasmic binding of the antibody but not to the extent observed in the nucleus. In agreement with the similarity score data, the total cellular IRF8 as well as nuclear IRF8 intensities decreased with peptide blocking. In healthy donor peripheral blood subpopulations and a positive control cell line (THP-1), the assessment of IRF8 by total cellular presence correlated well with its specific nuclear presence and correlated with the known distribution of IRF8 in these cells. In clinical samples of myeloid-derived suppressors cells derived from patients with renal carcinoma, however, total cellular IRF8 did not necessarily correlate with its nuclear presence. Discordance was primarily associated with peptide blocking having a proportionally greater effect on the IRF8 nuclear localization versus total fluorescence assessment. The data thus indicate that IRF8 can have cytoplasmic presence and that during disease its nuclear-cytoplasmic distribution may be altered, which may provide a basis for potential myeloid defects during certain pathologies.

Abstract 4225: Dynamic control of tumor vasculature with direct observation using intravital microscopy

Introduction

Intravital microscopy (IVM) provides in vivo real-time imaging of tumor-associated vasculature. Our group was the first to use IVM successfully in human subjects to image melanoma associated vessels. In this preclinical study, we hypothesized that intravenous (IV) nicardipine increases observable blood flow to tumor through vasodilatation and therefore may facilitate drug delivery.

Methods

Standard window chambers for IVM were implanted into female BALB/c mice. The murine colon cancer cell line CT26HA was inoculated in the skin within the chamber. Fluorescein isothiocyanate dextran (FITC-dex) was injected IV to enhance vessel observation prior to nicardipine (8 μg/mouse). Observations were performed at 100x magnification using a modified Olympus microscope for 10 minutes. Naïve mice were used for control observations. Mice bearing CT26HA were observed on post-inoculation day 5, 12 and 20. Vessel architecture and vessel diameter in response to nicardipine were compared.

Results

In non-CT26HA bearing mice, nicardipine resulted in a greater than 10% increase in skin vessel diameters directly measured using IVM (pre-nicardipine diameter 82.4 ± 3.6 μm versus post-nicardipine diameter 93.0 ± 3.9 μm. In CT26HA bearing mice, abnormal vessels were observed as early as day 7 even in the absence of a solid tumor mass. Vessel abnormalities included haphazard areas of increased vessel density, aberrant vessel branching patterns, nonfunctional vessels, and altered flow rates. Following nicardipine injection, the diameter of larger tumor-associated vessels did not increase and remained constant (pre: 111.2 ± 2.7 μm vs post: 109.1 ± 3.3 μm). Paradoxically, for smaller vessels (&lt; 20 μm), tumor-associated vessels vasoconstricted following nicardipine injection and returned to baseline diameter after approximately five minutes. Blood flow in these small vessels decreased or stopped during this observation.

Conclusions

Observation of dynamic vessel changes from vasoactive agents is feasible using IVM. For tumor-associated vessels, nicardipine was not shown to increase vessel diameter and counterintuitively decreased diameters of smaller vessels. Implication on drug delivery from vasoactive agents will lead to further pre-clinical study of applications for human IVM.

Citation Format: Emmanuel M. Gabriel, Daniel Fisher, Minhyung Kim, Colin Powers, Anthony Visioni, Jason Muhitch, Joseph Skitzki. Dynamic control of tumor vasculature with direct observation using intravital microscopy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4225.

Enhancing the antitumor effects of adoptive cell transfer immunotherapy using preconditioning thermal ablation (TUM7P.956)

A major challenge facing T cell based immunotherapeutic strategies is the limited trafficking of cytotoxic T cells at vascular checkpoints within the tumor microenvironment. Here, we report the use of radiofrequency ablation (RFA; 90°C, 1min), a cytoreductive strategy used clinically to treat unresectable tumors, as a pre-conditioning regimen to overcome deficient CD8 T trafficking across tumor vasculature. RFA pre-treatment caused a concomitant decrease in the number of Foxp3+CD4+CD25+ regulatory T cells while bolstering CD8 T cells in tumor draining lymph nodes and the non-ablated region within the tumor microenvironment. Taking advantage of the immunostimulatory activities of RFA, adoptive transfer of antigen-specific T cells was performed 6 hours post-RFA in implantable murine tumors (B16.F10 melanoma or CT26 colorectal tumors). Increased trafficking of adoptively transferred T cells was observed in both the tumor draining lymph node and tumor microenvironment. Improved trafficking was associated with a robust increase in antigen-restricted apoptosis of tumor cell targets and significantly enhanced overall survival without recurrence. Further investigation revealed that adoptive T cell transfer following RFA elicited a durable tumor-specific memory response. Taken together, these findings suggest that thermal ablative regimens may have clinical potential as an adjuvant to augment the efficacy of T cell-based cancer immunotherapies.

Negative impact of myeloid-derived suppressor cells on CD8 effector T cell trafficking within the tumor microenvironment (TUM4P.924)

The success of immunotherapy and, unexpectedly, chemotherapy and radiation hinges on cytotoxic T cells gaining access to tumor targets. These observations have prompted interest in developing strategies to improve T cell trafficking in tumors. Here, we report that the ability of tumor vessels to respond to IL-6-dependent preconditioning regimens that boost CD8 effector T cell homing is temporally and inversely related to the expansion of myeloid-derived suppressor cells (MDSC) within the tumor microenvironment. Using real-time intravital imaging and immunofluorescence histology, IL-6 therapies were shown to convert vessels from T cell-low to -high recruitment sites in murine tumors with minimal MDSC infiltration (i.e., CT26 colorectal, B16 melanoma, EMT6 mammary tumors). This conversion requires induction of the ICAM-1 trafficking molecule on tumor vessels. Conversely, mammary (4T1, AT-3 and PyMT-MMTV) and pancreatic (Pan02) tumors with high MDSC burdens were refractory to IL-6 therapies, but became responsive after acute MDSC depletion. To further investigate contributions of MDSC to poor trafficking, IL-6-responsive tumors were admixed at a ratio of 2:1 with MDSC from tumor-bearing mice. Sustained elevation of MDSC in admixed tumors resulted in failure to support increased T cell trafficking in response to IL-6-dependent therapy. Taken together, these findings identify a novel role for MDSC in immune evasion by limiting T cell trafficking at tumor vascular loci.

Delivery of signal 0 by dendritic cell-derived IL-6 promotes naïve T cell trafficking across high endothelial venules (P5098)

Dendritic cells (DC) are master regulators of adaptive immunity, providing cognate antigen (signal 1) and costimulation (signal 2) required for T cell activation in addition to cytokines (IL-12, TNF, IL-1 and IL-6; signal 3) that drive T cell expansion. Here we show that DC play an unexpected role in shaping the size of the naive T cell pool within draining nodes by promoting trafficking across vascular checkpoints termed high endothelial venules (HEV). Immunization with bone marrow-derived mouse DCs matured ex vivo by TLR4 or TLR9 agonists (LPS and ODN-CpG, respectively), but not a TLR2 agonist (Pam3CSK4), increased the density of two HEV homing molecules, peripheral lymph node addressin (PNAd) and intercellular adhesion molecule-1 (ICAM-1). Elevated PNAd and ICAM-1 supported increased trafficking of naïve T cells early in the adaptive immune response (12-48 h), preceding the peak phase of proliferative expansion of endothelial cells lining HEV in draining nodes. Loss of a single cytokine, IL-6, from CD11c+CD11b+CD8α- immunizing DC abrogated the early effects on HEV adhesion. Induction of HEV adhesion further required CCR7 chemokine receptor-dependent access of IL-6-producing DCs to afferent lymphatics at the immunization site. We propose that DC-derived IL-6 functions as a previously unrecognized signal 0 to fine-tune HEV adhesion, thereby increasing the probability that rare Ag-specific T cells receive activating signals during the initial phase of adaptive immunity.

Overcoming obstacles to naïve T lymphocyte trafficking in tumor-draining lymph nodes (46.47)

Effective tumor immune responses rely on trafficking of rare tumor-specific T cells to tumor-draining lymph nodes (TdLN) where they undergo activation and expansion, and subsequently to tumor tissues to gain access to neoplastic targets. Here, we evaluated the trafficking of naïve CD8 T cells to TdLN. Lymphocyte entry into TdLN was diminished by ~50% in mice bearing B16 melanoma, suggesting a localized mechanism of immune escape. Intravital microscopy revealed that while normal proportions of lymphocytes initiated tethering and rolling in high endothelial venules (HEV) of TdLN (34%), the fraction of lymphocytes that transitioned from rolling to firm arrest was reduced compared to unchallenged lymph nodes (8 and 20%, respectively). Diminished trafficking in TdLN was attributed to suboptimal presentation of the CCL21 chemokine in HEV. We further determined that inflammatory cues triggered by systemic thermal therapy (STT, 39.5 ± 0.5°C, 6 h) could restore normal T cell entry in TdLN, paralleling our previous findings in non-tumor-challenged mice. Improved homing was due to a reduction in rolling velocity and an increase in proportion of T cells undergoing firm arrest. STT was further shown to enhance the display of trafficking molecules required for firm arrest, i.e., CCL21 and ICAM-1 in HEV. These findings suggest that therapeutic targeting of HEVs for improved entry of naïve T cells in TdLN may be a novel strategy to overcome immune evasion.

Dendritic cells act through IL-6 to enhance naïve T cell trafficking across high endothelial venules during adaptive immunity (173.18)

Dendritic cells (DC) are as master regulators of the adaptive immune response, providing both cognate antigen and costimulation required for T cell activation as well as cytokines (e.g., IL-12, TNF, and IL-6) that drive T cell expansion and differentiation. While the role of DCs in T cell activation is well known, here we show that DCs play an unexpected role in shaping the T cell repertoire within inflamed lymph nodes (LN) by promoting trafficking across vascular gateways termed high endothelial venules (HEV). Immunization of mice with bone marrow-derived DCs matured ex vivo by TLR4 and 9 agonists (LPS and ODN-CpG, respectively), but not a TLR2 agonist (Pam3CSK4), increased the intravascular density of two hallmark adhesion molecules, peripheral lymph node addressin (PNAd) and intercellular adhesion molecule-1 (ICAM-1), selectively in HEVs of inflamed LNs. Increased PNAd and ICAM-1 display occurred rapidly after immunization (within 12 h) and coincided with improved trafficking of naïve and central memory T cells as well as increased LN size. PNAd and ICAM-1 expression reverted to homeostatic levels 24-48 h post immunization. Remarkably, increased adhesion molecule expression was abrogated by loss of a single cytokine, IL-6, from immunizing DCs. These findings suggest a model whereby IL-6-producing DC actively promote trafficking in HEVs, thereby increasing the probability that naïve T cells come into contact with cognate antigen-loaded DCs in inflamed LN.

Interferon inhibitory activity in patients with multiple sclerosis

BACKGROUND

Interferon inhibitory activity (IIA) is a logical candidate for explaining neutralizing antibody-negative partial responsiveness to interferon beta in multiple sclerosis (MS), but its role has not been evaluated.

OBJECTIVE

To investigate the role of IIA and soluble interferon-alpha/beta receptor (sIFNR) in determining response of patients with MS to interferon beta therapy.

DESIGN

Parallel-group, open-label study.

SETTING

Baird Multiple Sclerosis Center, Buffalo, NY. Patients Blood was obtained before and 24 hours after injection of interferon beta-1a from 38 anti-interferon beta neutralizing antibody-negative patients with relapsing-remitting MS and 16 untreated healthy controls. On the basis of clinical parameters of response to interferon beta therapy, the patients were divided into stable or good-responder (n = 20) and active or partial-responder (n = 18) groups.

MAIN OUTCOME MEASURES

Quantitative analyses of magnetic resonance imaging were obtained; the IIA and sIFNR levels were measured using bioassay and enzyme-linked immunosorbent assay, respectively.

RESULTS

The IIA and sIFNR levels were elevated in MS patients compared with controls (P<.001). The IIA levels were higher in active or partial responders compared with stable or good responders (P<.001); the sIFNR levels were not different between groups. The Extended Disability Status Score and T2 lesion volumes were higher in the active or partial-responder group compared with the stable or good-responder group. Interferon beta-1a did not have short-term effects on the IIA and sIFNR levels. In univariate general linear model and stepwise regression analyses, IIA levels were associated with T2 lesion volume.

CONCLUSION

The levels of IIA are associated with increased MS disease activity and with responsiveness to interferon beta therapy in anti-interferon beta neutralizing antibody-negative MS patients.