Digital health coaching to improve patient preparedness for elective lower limb arthroplasty: a quality improvement project

Major surgery carries high risks with comorbidities, frailty and health risk behaviours meaning patients are often unprepared for the physiological insult. Since 2018, the Prepwell programme at South Tees Hospitals NHS Foundation Trust has supported patients to improve their preoperative health and fitness. In April 2020, the face-to-face service was suspended due to the pandemic, leading to the team implementing a three-tiered remote digital support pathway, including digital health coaching via a mobile phone application.

METHODS

Patients scheduled for elective lower limb arthroplasty were offered 8 weeks of digital health coaching preoperatively. Following consent, participants were assigned a personal health coach to set individual behaviour change goals supported by online resources, alongside a digitally delivered exercise programme. Participants completed self-assessment questionnaires at Entry to, and Exit from, the programme, with outcome data collected 21 days postoperatively. The primary outcome was the change in Patient Activation Measure (PAM).

RESULTS

Fifty-seven of 189 patients (30.2%) consented to referral for digital health coaching. Forty participants completed the 8-week programme. Median PAM increased from 58.1 to 67.8 (p=0.002). Thirty-five per cent of participants were in a non-activated PAM level at Entry, reducing to 15% at Exit with no participants in PAM level 1 at completion. Seventy-one percent of non-activated participants improved their PAM by one level or more, compared with 45% for the whole cohort. Median LOS was 2 days, 1 day less than the Trust's arthroplasty patient population during the study period (unadjusted comparison).

CONCLUSIONS

Digital health coaching was successfully implemented for patients awaiting elective lower limb arthroplasty. We observed significant improvements in participants' PAM scores after the programme, with the largest increase in participants with lower activation scores at Entry. Further study is needed to confirm the effects of digital health coaching in this and other perioperative groups.

SARS-CoV-2 antibody response duration and neutralization following natural infection

Background

The role of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) neutralizing antibody response from natural infection and vaccination, and the potential determinants of this response are poorly understood. Characterizing this antibody response and the factors associated with neutralization can help inform future prevention efforts and improve clinical outcomes in those infected.

Objectives

The goals of this study were to prospectively evaluate SARS-CoV-2 antibody levels and the neutralizing antibody responses among naturally infected adults and to determine demographic and behavioral factors independently associated with these responses.

Methods

Serum was collected from seropositive individuals at baseline, four-weeks, and three-months following their first study visit to be evaluated for antibody levels. Detection of neutralizing antibodies was performed at baseline. Participant demographic and behavioral information was collected via web questionnaire prior to their first visit.

Results

At baseline, higher antibody levels were associated with better neutralization capacity, with 83% of participants having detectable neutralizing antibodies. We found an age-dependent effect on antibody level and neutralization capacity with participants over 65 years having significantly higher levels. Ethnicity, heart disease, autoimmune disease, and COVID symptoms were associated with higher antibody levels, but not with increased neutralization capacity. Work environment during the pandemic correlated with increased neutralization capacity, while kidney or liver disease and traveling out of state after February 2020 correlated with decreased neutralization capacity, however neither correlated with antibody levels.

Conclusions

Our data show that natural infection by SARS-CoV-2 can induce a humoral response reflected by high antibody levels and neutralization capacity.

Abstract 4055: CD40L stimulates melanoma infiltrating B cells and enhances ex vivo TIL expansion

Adoptive transfer of tumor infiltrating lymphocytes (TIL) is a feasible and effective therapy for melanoma and lung cancer[1,2]. Multiple factors may determine the quality of the TIL product including components of the tumor microenvironment. In this work, we analyzed the role of melanoma infiltrating B cells in the context of TIL expansion based on their documented association with response to other types of immunotherapies[3]. We stimulated melanoma infiltrating B cells using human recombinant CD40L on the first day of ex-vivo TIL expansion. Samples were expanded from cryopreserved melanoma tumor single cell suspensions, in high dose IL-2 alone (standard protocol), or in high dose IL-2 plus CD40L. After 48h, analysis of activation markers on the CD40-expressing cells by flow cytometry was performed. For further investigation of the changes induced by CD40L stimulation, TIL expansion cultures (+/- CD40L) were analyzed using scRNA-seq (10X Genomics Chromium NextGEM Single Cell 5’ v2 and V(D)J Reagent kits; Illumina NovaSeq 6000 instrument with S4 sequencing flow cell) at 48h of culture (n=7 patients). The TIL expansion success rate was 68% with the CD40L treatment condition compared to 36% with the standard protocol. TILs cultured in the presence of CD40L expanded to on average three times more than with the standard protocol (P ≤ 0.01). Treatment with CD40L increased the percentage of CD39- CD69- T cells (P ≤ 0.05). Within the tumor digests, a higher percentage of B cells, including switched memory B cells (CD27+ IgD− ), was associated with successful TIL expansion (P=0.04). scRNA-seq analysis demonstrated different clustering patterns within the B cell compartment based on culture conditions. No clear partition was observed for other cell types, including the myeloid compartment. B cells displayed 126 DEGs associated to CD40L addition, CCL22, CD83, EBI3 and CD58 were among the upregulated genes in the CD40L-treated B cells. Other cell types experienced minimal to no change in transcriptomic profiles. B cell clusters were sub-classified based on CD27 and IgD expression[4], showing a predominance of naïve and switched memory B cells. Our results show that higher presence of B cells within tumors is associated with better TIL expansion, suggesting an interplay between T and B cells, and providing rationale for the design of improved TIL expansion protocols based on B cell stimulation with CD40L. This work has been supported in part by the Flow Cytometry, Genomics and Biostatistics and Bioinformatics Core Facilities at Moffitt Cancer Center, an NCI designated Comprehensive Cancer Center (P30-CA076292). We acknowledge Moffitt’s Melanoma Center of Excellence and the Mark Foundation for the financial support. [1] Sarnaik, A.A. et al. JCO 39, 2656-2666 (2021). [2] Creelan, B. et al. Nat Med 27, 1410-1418 (2021). [3] Cabrita, R. et al. Nature 577, 561-565 (2020). [4] Sanz, I. et al. Front Immunol 10, 2458 (2019).

Citation Format: Renata Ariza Marques Rossetti, Leticia Tordesillas, Matthew Beatty, Dongliang Du, Yian Ann Chen, Amod Sarnaik, Shari Pilon-Thomas, Daniel Abate-Daga. CD40L stimulates melanoma infiltrating B cells and enhances ex vivo TIL expansion. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4055.

Fucosylation of HLA-DRB1 regulates CD4+ T cell-mediated anti-melanoma immunity and enhances immunotherapy efficacy

Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs); thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the major histocompatibility complex (MHC)-II protein HLA-DRB1 in melanoma cells, triggering CD4+ T cell-mediated increases in itICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-programmed cell death protein 1 (PD1) responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity and, importantly, suggest that L-fucose is a powerful agent for safely increasing itICs and immunotherapy efficacy in melanoma.

Severe maternal morbidity in Scotland

Using a cohort study design, we analysed 17 diagnoses and 9 interventions (including critical care admission) as a composite measure of severe maternal morbidity for pregnancies recorded over 14 years in Scotland. There were 762,918 pregnancies, of which 7947 (10 in 1000 pregnancies) recorded 9345 severe maternal morbidity events, 2802 episodes of puerperal sepsis being the most common (30%). Severe maternal morbidity incidence increased from 9 in 1000 pregnancies in 2012 to 17 in 1000 pregnancies in 2018, due in part to puerperal sepsis recording. The odds ratio (95%CI) for severe maternal morbidity was higher for: older women, for instance 1.22 (1.13-1.33) for women aged 35-39 years and 1.44 (1.27-1.63) for women aged > 40 years compared with those aged 25-29 years; obese women, for instance 1.13 (1.06-1.21) for BMI 30-40 kg.m-2 and 1.32 (1.15-1.51) for BMI > 40 kg.m-2 compared with BMI 18.5-24.9 kg.m-2 ; multiple pregnancy, 2.39 (2.09-2.74); and previous caesarean delivery, 1.52 (1.40-1.65). The median (IQR [range]) hospital stay was 3 (2-5 [1-8]) days with severe maternal morbidity and 2 (1-3 [1-5]) days without. Forty-one women died during pregnancy or up to 42 days after delivery, representing mortality rates per 100,000 pregnancies of about 365 with severe maternal morbidity and 1.6 without. There were 1449 women admitted to critical care, 807 (58%) for mechanical ventilation or support of at least two organs. We recorded an incidence of severe maternal morbidity higher than previously published, possibly because sepsis was coded inaccurately in our databases. Further research may determine the value of this composite measure of severe maternal morbidity.

Passively scanned, single-fiber optical coherence tomography probes for gastrointestinal devices

BACKGROUND/OBJECTIVES

Optical coherence tomography (OCT) uses low coherence interferometry to obtain depth-resolved tissue reflectivity profiles (M-mode) and transverse beam scanning to create images of two-dimensional tissue morphology (B-mode). Endoscopic OCT imaging probes typically employ proximal or distal mechanical beam scanning mechanisms that increase cost, complexity, and size. Here, we demonstrate in the gastrointestinal (GI) tracts of unsedated human patients, that a passive, single-fiber probe can be used to guide device placement, conduct device-tissue physical contact sensing, and obtain two-dimensional OCT images via M-to-B-mode conversion.

MATERIALS AND METHODS

We designed and developed ultrasmall, manually scannable, side- and forward-viewing single fiber-optic probes that can capture M-mode OCT data. Side-viewing M-mode OCT probes were incorporated into brush biopsy devices designed to harvest the microbiome and forward-viewing M-mode OCT probes were integrated into devices that measure intestinal potential difference (IPD). The M-mode OCT probe-coupled devices were utilized in the GI tract in six unsedated patients in vivo. M-mode data were converted into B-mode images using an M-to-B-mode conversion algorithm. The effectiveness of physical contact sensing by the M-mode OCT probes was assessed by comparing the variances of the IPD values when the probe was in physical contact with the tissue versus when it was not. The capacity of forward- and side-viewing M-mode OCT probes to produce high-quality B-mode images was compared by computing the percentages of the M-to-B-mode images that showed close contact between the probe and the luminal surface. Passively scanned M-to-B-mode images were qualitatively compared to B-mode images obtained by mechanical scanning OCT tethered capsule endomicroscopy (TCE) imaging devices.

RESULTS

The incorporation of M-mode OCT probes in these nonendoscopic GI devices safely and effectively enabled M-mode OCT imaging, facilitating real-time device placement guidance and contact sensing in vivo. Results showed that M-mode OCT contact sensing improved the variance of IPD measurements threefold and side-viewing probes increased M-to-B-mode image visibility by 10%. Images of the esophagus, stomach, and duodenum generated by the passively scanned probes and M-to-B-mode conversion were qualitatively superior to B-mode images obtained by mechanically scanning OCT TCE devices.

CONCLUSION

These results show that passive, single optical fiber OCT probes can be effectively utilized for nonendoscopic device placement guidance, device contact sensing, and two-dimensional morphologic imaging in the human GI tract in vivo. Due to their small size, lower cost, and reduced complexity, these M-mode OCT probes may provide an easier avenue for the incorporation of OCT functionality into endoscopic/nonendoscopic devices.

Feasibility and Safety of Tethered Capsule Endomicroscopy in Patients With Barrett's Esophagus in a Multi-Center Study

BACKGROUND & AIMS

Tethered capsule endomicroscopy (TCE) involves swallowing a small tethered pill that implements optical coherence tomography (OCT) imaging, procuring high resolution images of the whole esophagus. Here, we demonstrate and evaluate the feasibility and safety of TCE and a portable OCT imaging system in patients with Barrett's esophagus (BE) in a multi-center (5-site) clinical study.

METHODS

Untreated patients with BE as per endoscopic biopsy diagnosis were eligible to participate in the study. TCE procedures were performed in unsedated patients by either doctors or nurses. After the capsule was swallowed, the device continuously obtained 10-μm-resolution cross-sectional images as it traversed the esophagus. Following imaging, the device was withdrawn through mouth, and disinfected for subsequent reuse. BE lengths were compared to endoscopy findings when available. OCT-TCE images were compared to volumetric laser endomicroscopy (VLE) images from a patient who had undergone VLE on the same day as TCE.

RESULTS

147 patients with BE were enrolled across all sites. 116 swallowed the capsule (79%), 95/114 (83.3%) men and 21/33 (63.6%) women (P = .01). High-quality OCT images were obtained in 104/111 swallowers (93.7%) who completed the procedure. The average imaging duration was 5.55 ± 1.92 minutes. The mean length of esophagus imaged per patient was 21.69 ± 5.90 cm. A blinded comparison of maximum extent of BE measured by OCT-TCE and EGD showed a strong correlation (r = 0.77-0.79). OCT-TCE images were of similar quality to those obtained by OCT-VLE.

CONCLUSIONS

The capabilities of TCE to be used across multiple sites, be administered to unsedated patients by either physicians or nurses who are not expert in OCT-TCE, and to rapidly and safely evaluate the microscopic structure of the esophagus make it an emerging tool for screening and surveillance of BE patients. Clinical trial registry website and trial number: NCT02994693 and NCT03459339.

Early recovery of myeloid-derived suppressor cells after allogeneic hematopoietic cells: comparison of post-transplantation cyclophosphamide to standard graft-versus-host disease prophylaxis

BACKGROUND

Allogeneic hematopoietic cell transplantation (alloHCT) using haploidentical donors (haploHCT) with post-transplantation cyclophosphamide (PTCy) for augmented graft-versus-host disease (GVHD) prophylaxis has emerged as a robust platform to expand donor options with acceptable levels of GVHD and graft failure. The mechanism by which PTCy mitigates GVHD risk is partly explained by preferential cytotoxicity based on aldehyde dehydrogenase levels and up-regulation of regulatory T cells, but is incompletely understood. Myeloid-derived suppressor cells are important mediators of T-cell function and are up-regulated by cyclophosphamide exposure.

OBJECTIVES

We hypothesized that this cell type may play a role in GVHD protection in children undergoing haploHCT/PTCy.

STUDY DESIGN

We prospectively collected samples in the first month after alloHCT from children undergoing standard of care (SOC) alloHCT with matched donors and tacrolimus-based GVHD prophylaxis (N=11) and PTCy recipients (N=11). MDSC recovery was compared using flow cytometry, and MDSC suppressive function was assessed at the peak of MDSC quantitative recovery post-alloHCT.

RESULTS

Groups were well matched for conditioning regimen and stem cell source. PTCy recipients exhibited more robust MDSC recovery, particularly polymorphonuclear-MDSCs than SOC recipients, with preservation of T-cell suppressive function. This corresponded to significantly lower incidence of Grade II-IV acute GVHD (9.1% versus 27.3%) and moderate/severe chronic GVHD (0% versus 27.3%) in PTCy recipients. Patients who developed GVHD had decreased MDSC-mediated T-cell suppression, as well as higher levels of IL-10, a cytokine closely linked to GVHD biology.

CONCLUSION

Overall, these findings provide support for the role of MDSCs in mediating GVHD protection after PTCy-based haploHCT.

385 Identification and enrichment of neoantigen-reactive T cells to optimize adoptive cell transfer with tumor-infiltrating lymphocytes (TIL)

Background

Adoptive cell transfer (ACT) using tumor-infiltrating lymphocytes (TIL) has achieved an overall response rate of 39% in metastatic melanoma patients at Moffitt Cancer Center. In these trials, a substantial fraction of patients were non-responders by RECIST, but demonstrated a mixed response to therapy. These results suggest that the infused TIL product contained tumor-reactive T cells with therapeutic potential, which could be further optimized to improve ACT with TIL. We hypothesized that outcomes might be improved by identifying and enriching neoantigen-reactive TIL within bulk products. The purpose of this study is to define approaches to optimize ACT with TIL, by identifying, enriching, and analyzing neoantigen reactive TIL from the ACT infusion product of previously treated metastatic melanoma patients.

Methods

Patient-derived cryopreserved tumor tissue, PBMC, and TIL from completed metastatic melanoma TIL trials were used for this study. Whole exome and RNA sequencing were performed on DNA and RNA extracted from tumor tissue and compared to DNA from autologous PBMC. Genetic sequencing and gene expression data were utilized to determine protein-modifying somatic mutations. Peptides were then predicted for their ability to be presented on MHC molecules, prioritized, and up to 192 custom 25-mers were synthesized per patient sample. Neoantigen peptides were loaded onto patient-derived dendritic cells (DC) and co-cultured with autologous TIL. These TIL were then sorted by FACS on their ability to upregulate 41BB and OX40 and expanded through the rapid expansion protocol (REP). Enriched TIL were subsequently screened for neoantigen reactivity by 41BB/OX40 upregulation, cytokine release, and degranulation.

Results

Protein-altering somatic mutations from metastatic melanoma tissues ranged from 49 to 1631 mutations (median = 389). On average, 16.2% of TIL were sorted for upregulation of 41BB/OX40 upon co-culture with DC pulsed with the neoantigen peptide pool (range: 2.7–31.1%). CD4+ TIL displayed a 3.75-fold upregulation of 41BB/OX40, while CD8+ TIL saw a 1.88-fold increase (n=6). This coincided with substantial production of IFNγ, TNFα, and granzyme B (n=6). Neoantigen-reactive (41BB+/OX40+) and non-reactive (41BB-/OX40-) TIL expanded to similar degrees in REP (average of 639-fold vs. 611-fold; n=6). Restimulation of enriched neoantigen-specific TIL resulted in superior pro-inflammatory functionality (granzyme B, IFNγ, and TNFα) when compared to non-reactive TIL.

Conclusions

TIL from metastatic melanoma patient samples were successfully enriched for neoantigen-reactive TIL, which maintained increased reactivity against these predicted peptides upon restimulation when compared non-reactive TIL. These data support further investigation into the use of neoantigen-enriched TIL products to enhance efficacy of ACT.

Trial Registration

NCT01005745, NCT01659151, NCT01701674

Ethics Approval

NCT01005745 was approved by USF IRB approval number Ame5_107905.NCT01659151 was approved by Advarra IRB approval number 14.03.0083.NCT01701674 was approved by USF IRB approval number Ame13_Pro00009061.All participants gave informed consent before taking part.

195 Stimulation of tumor infiltrating B-cells improves ex-vivo TIL expansion for melanoma immunotherapy

Background

The immunogenic nature of melanoma has been exploited for the development of adoptive transfer of ex-vivo expanded tumor infiltrating lymphocytes (TIL). This adoptive cell transfer therapy has overall response rates of around 50%. Multiple factors may determine the quality of the TIL product including components of the tumor microenvironment. B-cells are frequently found in melanoma metastasis, and display signs of antigen experience. Recently, B-cell tumor infiltration has been associated with improved clinical responses to immune checkpoint inhibitors,1 2 but their role in TIL therapy remains unexplored. Considering the potential role of B cells, we aim to develop strategies to enhance the quality of TIL products through B-cell stimulation during ex-vivo TIL expansion.

Methods

We stimulated melanoma infiltrating B-cells using human recombinant CD40L on the first day of ex-vivo TIL expansion. Thirteen samples were expanded from melanoma tumor single cell suspensions, in high dose IL-2 alone (standard protocol), or in high dose IL-2 plus CD40L. After up to four weeks of expansion, the TIL phenotype was analyzed by flow cytometry.

Results

The expansion success rate from the frozen tumor digests was 69% (95% CI: 38.6–90.9%) in the CD40L treatment condition compared to 23% with the standard protocol. Also, TILs cultured in the presence of CD40L expanded to higher numbers than with the standard protocol (P = 0.02). Interestingly, most of the samples expanded with CD40L had a significant increase in the percentage of CD4+ T cells (P = 0.03), but not to the detriment of the absolute number of CD8+ T cells. Treatment with CD40L increased the percentage of effector memory-like T cells (P = 0.03) and of CD39- CD69- T cells (P < 0.05), which were recently associated with response to TIL therapy.3

Conclusions

This preliminary work demonstrates that the stimulation with CD40L at the initiation of TIL culture leads to enhanced TIL expansion and an increase in CD4+ T cells with an effector memory-like and stem-like phenotype. Our group and others have previously described cases of patients who had tumor regression after receiving TIL therapy that were predominantly CD4+ T cells, suggesting that expansion of the CD4+ TIL repertoire may enhance TIL therapy.4

Acknowledgements

This work has been supported in part by the Flow Cytometry, Genomics and Biostatistics and Bioinformatics Core Facilities at Moffitt Cancer Center, an NCI designated Comprehensive Cancer Center (P30-CA076292). We acknowledge Moffitt’s Melanoma Center of Excellence for the financial support.

References

Cabrita R, Lauss M, Sanna A. Tertiary lymphoid structures improve immunotherapy and survival in melanoma. Nature 2020;577:561–565.

Petitprez F, de Reynies A, Keung EZ. B cells are associated with survival and immunotherapy response in sarcoma. Nature 2020;577:556–560.

Krishna S, Lowery FJ, Copeland AR. Stem-like CD8 T cells mediate response of adoptive cell immunotherapy against human cancer. Science 2020;370:1328–1334.

Friedman KM, Prieto PA, Devillier LE. Tumor-specific CD4+ melanoma tumor-infiltrating lymphocytes. J Immunother 2012;35:400–408.

Ethics Approval

The study was approved by Advarra IRB, approval number MCC20559.

384 An investigation into the role of CD4+ tumor-infiltrating lymphocytes (TIL) in metastatic melanoma patients with a complete response to adoptive cell therapy

Background

Immunotherapy for cancer has long been focused on the generation of CD8+ cytotoxic T lymphocyte responses, independent of their dynamic CD4+ T cell counterpart. One promising approach, adoptive cell transfer (ACT) of tumor-infiltrating lymphocytes (TIL), has yielded response rates ranging from 28–55%.1–2 Investigation into the role of CD4+ TIL in this setting remains critically underexplored as an opportunity to improve upon these successes.

Methods

Two metastatic melanoma patients (PT1 and PT2) were treated with TIL on a completed clinical trial at Moffitt Cancer Center (NCT01005745). Tumor recognition by TIL was assessed via co-culture with tumor. Whole exome (WES) and RNA Sequencing were performed on cryopreserved tumor sections and mutant peptide-MHC binding was predicted. TIL were stimulated with antigen presenting cells (APCs) loaded with neoantigen-derived 25mer peptides and sorted based on 41BB/OX40 upregulation, followed by functional immunologic assays. TCR sequencing was conducted on patient peripheral blood as well as isolated neoantigen-specific TIL clones to determine persistence in vivo and cognate peptide-MHC targets were determined empirically.

Results

PT1, infused with predominantly CD4+ TIL (88%), achieved a complete response (CR) despite lack of IFNγ detection with conventional in vitro tumor co-culture methods. Infusion product TIL were sorted by upregulation of OX40 and 41BB upon stimulation with APCs loaded with the mutant peptide pool. Neoantigen reactivity arose from a single peptide sequence, which conferred recognition by a CD4+ TIL clone, which comprised 17% of the infusion product and enriched to greater than 80% after sorting via FACS. These CD4+ TIL produced IFNγ, TNFα, and granzyme B in response to peptide-loaded APCs in an HLA-DR dependent manner. TCRβ overlap revealed this CD4+ clone peaked at two weeks post-infusion (40%) and persisted after infusion for at least six weeks. PT2 was infused with highly reactive, primarily CD8+ (88%) TIL and also achieved a CR. Isolated CD4+ TIL were also responsive to tumor antigens in the context of MHC Class II in vitro. Tumor-reactive CD4+ TIL were enriched by IFNγ capture and delayed xenograft growth in vivo (p<0.01). Neoantigen peptides stimulated predominantly CD4+ TIL to upregulate OX40/41BB and produce IFNγ, TNFα, and granzyme B.

Conclusions

Investigation of these case studies demonstrated evidence of CD4+ TIL involvement in complete clinical responses after ACT. Ongoing studies will define the precise role of tumor-reactive CD4+ T cells in the anti-tumor immune response and provide the framework for future investigation into their function and therapeutic efficacy.

Trial Registration

NCT01005745

References

Bailey SR, et al. Human CD26high T cells elicit tumor immunity against multiple malignancies via enhanced migration and persistence. Nat Commun 2017;8(1):1961.

Tran E, et al. Cancer immunotherapy based on mutation-specific CD4+ T cells in a patient with epithelial cancer. Science 2014;344(6184):641–5.

Ethics Approval

Approved by USF IRB approval number Ame5_107905. All participants gave informed consent before taking part.

Systemic and intravesical adoptive cell therapy of tumor-reactive T cells can decrease bladder tumor growth in vivo

BACKGROUND

The therapeutic armamentarium of bladder cancer has been recently enriched with the introduction of new therapies including immune checkpoint inhibitors, receptor tyrosine kinase inhibitors and antibody drug conjugates, however treatment responses and duration of responses are still less than expected. Adoptive cellular therapy (ACT) using tumor-infiltrating lymphocytes (TILs) has potential to treat bladder cancer, as previously demonstrated by successful expansion of tumor reactive T cells from human bladder tumors.

METHODS

A model system using OT-I T cells and an ovalbumin expressing MB49 tumor cell line (MB49OVA) was developed to study ACT in bladder cancer. Systemic ACT-treated mice were given T cells intravenously after lymphodepleting chemotherapy and followed by interleukin (IL)-2 administration. Intravesical ACT treated mice were given T cells directly into the bladder, without chemotherapy or IL-2. TILs were isolated from MB49 orthotopic tumors and expanded ex vivo in IL-2. Immune cell infiltrates were analyzed by flow cytometry. T cell infiltration was studied using a CXCR3 blocking antibody.

RESULTS

Systemic ACT-treated mice had a decrease in tumor growth, increase in T cell infiltration and long-term immune protection compared with control-treated mice. OT-I T cells delivered intravesically were able to control tumor growth without lymphodepleting chemotherapy or IL-2 in MB49OVA orthotopic tumors. Intravesical delivery of TIL expanded from MB49 tumors was also able to decrease tumor growth in mice with MB49 orthotopic tumors. Blocking CXCR3 on OT-I T cells prior to intravesical delivery decreased T cell infiltration into the tumor and prevented the control of tumor growth.

CONCLUSIONS

This study demonstrates how TIL therapy can be used in treating different stages of bladder cancer.

Abstract 1513: A case study investigation into the role of CD4+ tumor-infiltrating lymphocytes in a metastatic melanoma patient with a complete response to adoptive cell therapy

Immunotherapy for cancer has long been focused on the generation of CD8+ cytotoxic T lymphocyte responses, independent of their dynamic CD4+ T cell counterpart. One promising approach, adoptive cell transfer (ACT) of tumor-infiltrating lymphocytes (TIL), has yielded response rates ranging from 28-55%. Although lasting and complete responses have been achieved, there is substantial opportunity for improvement. Investigation into the role of CD4+ TIL in this setting remains critically underexplored. CD4+ T cells recognize tumor antigen presented on MHC Class II either directly on tumor cells or indirectly through antigen presenting cells (APCs) and are able to elicit potent anti-tumor responses under the appropriate conditions. Here, we present a case study of a metastatic melanoma patient who received adoptive transfer of a predominantly (88%) CD4+ TIL product. This patient demonstrated a complete response (CR) to therapy despite a lack of detection of IFNg in the infusion product in vitro when these TIL were co-cultured with autologous tumor prior to ACT. Tumor recognition was also absent when CD8+ TIL were isolated and stimulated directly with HLA-matched tumor lines, indicating a lack of recognition of shared melanoma antigens presented on MHC Class I. Longitudinal analysis of the peripheral blood of this patient confirmed that the infused CD4+ TIL persisted after therapy for at least six weeks. Whole exome sequencing (WES) performed on the TIL surgical specimen discovered 88 non-synonymous single nucleotide variants (SNVs) as candidate neoantigens. Predicted binding of the resulting mutant peptides to autologous HLA molecules generated a predominantly MHC Class II restricted profile, with 81.8% of variants capable of MHC Class II presentation and greater than half exclusive to MHC Class II only. CD4+ TIL were screened for tumor antigen recognition by upregulation of OX40 and 41BB after stimulation with autologous APCs loaded with mutant peptides. Nearly half (49.2%) of CD4+ TIL responded to tumor-derived peptides. These CD4+ TIL were then sorted into tumor-reactive and non-reactive subsets for further clonal analysis of phenotype and transcriptional profile (scRNASeq) of these T cells in order to characterize the nature of the CD4+ TIL response to tumor antigen. Overall, thorough interrogation of this patient's case study demonstrated evidence of CD4+ TIL involvement in a complete clinical response after ACT. Ongoing studies will define the precise role of tumor-reactive CD4+ T cells in the anti-tumor immune response and provide the framework for future investigation into their function and therapeutic efficacy.

Citation Format: MacLean Hall, Pat Innamarato, Amy Mackay, Holly Branthoover, Alex Alfaro, Carolyn Rich, Allison Richards, Jonathan Hensel, Matthew Beatty, John Mullinax, Amod A. Sarnaik, Shari Pilon-Thomas. A case study investigation into the role of CD4+ tumor-infiltrating lymphocytes in a metastatic melanoma patient with a complete response to adoptive cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1513.

Intralesional injection of rose bengal augments the efficacy of gemcitabine chemotherapy against pancreatic tumors

BACKGROUND

Chemotherapy regimens that include the utilization of gemcitabine are the standard of care in pancreatic cancer patients. However, most patients with advanced pancreatic cancer die within the first 2 years after diagnosis, even when treated with standard of care chemotherapy. This study aims to explore combination therapies that could boost the efficacy of standard of care regimens in pancreatic cancer patients.

METHODS

In this study, we used PV-10, a 10% solution of rose bengal, to induce the death of human pancreatic tumor cells in vitro. Murine in vivo studies were carried out to examine the effectiveness of the direct injection of PV-10 into syngeneic pancreatic tumors in causing lesion-specific ablation. Intralesional PV-10 treatment was combined with systemic gemcitabine treatment in tumor-bearing mice to investigate the control of growth among treated tumors and distal uninjected tumors. The involvement of the immune-mediated clearance of tumors was examined in immunogenic tumor models that express ovalbumin (OVA).

RESULTS

In this study, we demonstrate that the injection of PV-10 into mouse pancreatic tumors caused lesion-specific ablation. We show that the combination of intralesional PV-10 with the systemic administration of gemcitabine caused lesion-specific ablation and delayed the growth of distal uninjected tumors. We observed that this treatment strategy was markedly more successful in immunogenic tumors that express the neoantigen OVA, suggesting that the combination therapy enhanced the immune clearance of tumors. Moreover, the regression of tumors in mice that received PV-10 in combination with gemcitabine was associated with the depletion of splenic CD11b+Gr-1+ cells and increases in damage associated molecular patterns HMGB1, S100A8, and IL-1α.

CONCLUSIONS

These results demonstrate that intralesional therapy with PV-10 in combination with gemcitabine can enhance anti-tumor activity against pancreatic tumors and raises the potential for this strategy to be used for the treatment of patients with pancreatic cancer.

The Factors Affecting Expansion of Reactive Tumor Infiltrating Lymphocytes (TIL) From Bladder Cancer and Potential Therapeutic Applications

Tumor infiltrating lymphocytes (TIL) therapy was shown to provide durable objective response in patients with metastatic melanoma. As a fundamental first step to bring TIL therapy to clinical use, identification of patients whose tumors yield optimal numbers of reactive TIL is indispensable. We have previously shown that expansion of tumor reactive TIL from primary bladder tumors and lymph node metastases is feasible. Here, we performed TIL harvesting from additional surgical specimens (additional 31 primary tumors and 10 lymph nodes) to generate a heterogenous cohort of 53 patients with bladder cancer (BC) to evaluate the tumor characteristics that lead to tumor-reactive TIL expansion. Among a total of 53 patients, overall TIL growth from tumor samples were 37/53 (69.8%) and overall anti-tumor reactive TIL were 26/35 (74.3%). Mixed urothelial carcinoma is associated with higher anti-tumor reactivity of expanded TIL than pure urothelial carcinoma (89.5% vs. 56.3%, p=0.049). The anti-tumor reactivity of expanded TIL from primary tumors previously treated with BCG immunotherapy were lower (33.3% vs. 82.6%, p=0.027) although T-cell phenotype (CD3+, CD4+, CD8+, and CD56+) was similar regardless prior of BCG therapy. Addition of agonistic 4-1BB antibody in culture media with IL-2 improved the number of expanded TIL from primary tumors previously treated with BCG immunotherapy. There was no significant difference between basal and luminal subtype tumors in terms of viable and reactive TIL growth. Our study demonstrates that TIL expansion is feasible across all BC patients and BC subtypes, and we suggest that TIL therapy can be a reasonable treatment strategy for various manifestations of BC.

Expansion of tumor-infiltrating lymphocytes (TIL) from penile cancer patients

Penile cancer is a rare but highly lethal cancer, and therapeutic options for patients presenting with lymph nodal disease are very limited. Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TIL) was shown to provide durable objective response in patients with metastatic melanoma and TIL have been expanded from solid tumors at rates between 70 and 90% depending on the specific diagnosis. We evaluated whether TIL could be expanded from surgical specimens of patients with penile cancer. Tumor samples from metastatic lymph nodes obtained at the time of inguinal lymph node dissection were collected, minced into fragments, placed in individual wells of a 24-well plate, and propagated in high dose IL-2 for four weeks. The phenotype of expanded TILs was assessed by flow cytometry and their anti-tumor reactivity was assessed by IFN-γ ELISA. TIL were expanded from 11 out of 12 (91.6%) samples of metastatic lymph nodes. Expanded TIL were predominantly CD3⁺ (mean 67.5%, SD 19.4%) with a mean of 46.8% CD8⁺ T cells (SD 21.1%). Five out of 11 samples (45.4%) from expanded TIL secreted IFN-γ in response to autologous tumor. TIL expansion and phenotype of expanded T cell lymphocytes were independent of previous HPV infection and treatment with neoadjuvant chemotherapy. This is the first report demonstrating successful expansion of tumor-reactive TIL from penile cancer patients, which support development of ACT strategies using TIL for the treatment of advanced and recurrent penile cancer.

Development and Validation of Risk Scores for All-Cause Mortality for a Smartphone-Based "General Health Score" App: Prospective Cohort Study Using the UK Biobank

Background

Given the established links between an individual’s behaviors and lifestyle factors and potentially adverse health outcomes, univariate or simple multivariate health metrics and scores have been developed to quantify general health at a given point in time and estimate risk of negative future outcomes. However, these health metrics may be challenging for widespread use and are unlikely to be successful at capturing the broader determinants of health in the general population. Hence, there is a need for a multidimensional yet widely employable and accessible way to obtain a comprehensive health metric.

Objective

The objective of the study was to develop and validate a novel, easily interpretable, points-based health score (“C-Score”) derived from metrics measurable using smartphone components and iterations thereof that utilize statistical modeling and machine learning (ML) approaches.

Methods

A literature review was conducted to identify relevant predictor variables for inclusion in the first iteration of a points-based model. This was followed by a prospective cohort study in a UK Biobank population for the purposes of validating the C-Score and developing and comparatively validating variations of the score using statistical and ML models to assess the balance between expediency and ease of interpretability and model complexity. Primary and secondary outcome measures were discrimination of a points-based score for all-cause mortality within 10 years (Harrell c-statistic) and discrimination and calibration of Cox proportional hazards models and ML models that incorporate C-Score values (or raw data inputs) and other predictors to predict the risk of all-cause mortality within 10 years.

Results

The study cohort comprised 420,560 individuals. During a cohort follow-up of 4,526,452 person-years, there were 16,188 deaths from any cause (3.85%). The points-based model had good discrimination (c-statistic=0.66). There was a 31% relative reduction in risk of all-cause mortality per decile of increasing C-Score (hazard ratio of 0.69, 95% CI 0.663-0.675). A Cox model integrating age and C-Score had improved discrimination (8 percentage points; c-statistic=0.74) and good calibration. ML approaches did not offer improved discrimination over statistical modeling.

Conclusions

The novel health metric (“C-Score”) has good predictive capabilities for all-cause mortality within 10 years. Embedding the C-Score within a smartphone app may represent a useful tool for democratized, individualized health risk prediction. A simple Cox model using C-Score and age balances parsimony and accuracy of risk predictions and could be used to produce absolute risk estimations for app users.

Expanded Tumor-infiltrating Lymphocytes From Soft Tissue Sarcoma Have Tumor-specific Function

Adoptive cell transfer (ACT) with tumor-infiltrating lymphocytes (TILs) can generate durable clinical responses in patients with metastatic melanoma and ongoing trials are evaluating efficacy in other advanced solid tumors. The aim of this study was to develop methods for the expansion of tumor-reactive TIL from resected soft tissue sarcoma to a degree required for the ACT. From 2015 to 2018, 70 patients were consented to an institutional review board-approved protocol, and fresh surgical specimens were taken directly from the operating room to the laboratory. Fragments of the tumor (1 mm3) or fresh tumor digest were placed in culture for a period of 4 weeks. Successfully propagated TIL from these cultures were collected and analyzed by flow cytometry. TIL were cocultured with autologous tumor and function was assessed by measurement of interferon-γ in the supernatant by enzyme-linked immunosorbent assay. Initial TIL cultures were further expanded using a rapid expansion protocol. Nearly all specimens generated an initial TIL culture (91% fragment method, 100% digest method). The phenotype of the TIL indicated a predominant CD3+ population after culture (43% fragment, 52% digest) and TIL were responsive to the autologous tumor (56% fragment, 40% digest). The cultured TIL expanded to a degree required for clinical use following rapid expansion protocol (median: 490-fold fragment, 403-fold digest). The data demonstrate the feasibility of TIL culture from fresh soft tissue sarcoma. The derived TIL have tumor-specific reactivity and can be expanded to clinically relevant numbers. An active ACT clinical trial using the methods described in this report is now approved for patients with metastatic soft tissue sarcoma.

T-cells produce acidic niches in lymph nodes to suppress their own effector functions

The acidic pH of tumors profoundly inhibits effector functions of activated CD8 + T-cells. We hypothesize that this is a physiological process in immune regulation, and that it occurs within lymph nodes (LNs), which are likely acidic because of low convective flow and high glucose metabolism. Here we show by in vivo fluorescence and MR imaging, that LN paracortical zones are profoundly acidic. These acidic niches are absent in athymic Nu/Nu and lymphodepleted mice, implicating T-cells in the acidifying process. T-cell glycolysis is inhibited at the low pH observed in LNs. We show that this is due to acid inhibition of monocarboxylate transporters (MCTs), resulting in a negative feedback on glycolytic rate. Importantly, we demonstrate that this acid pH does not hinder initial activation of naïve T-cells by dendritic cells. Thus, we describe an acidic niche within the immune system, and demonstrate its physiological role in regulating T-cell activation.

Abstract 2178: Expansion of tumor-specific tumor-infiltrating lymphocytes (TIL) from head and neck tumors

Background: Until recently, treatment options for patients with head and neck cancer include a combination of surgery, chemotherapy and radiation. Although the combined use of these treatment options modestly improves survival, combination therapy increases toxicity. Overall survival of these treatment regimens for patients with advanced head and neck cancer is just over 10 months. Even with the newly approved and vastly more tolerable use of anti-PD-1 immunotherapy, survival is only extended by 3-5 months. In comparison, adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TIL) has improved the median overall survival in patients with metastatic melanoma to 52 months. The goal of this study was to test the feasibility of expanding tumor-reactive TIL from head and neck tumors for the development of a clinical trial.

Methods: Primary tumors were resected from 20 head and neck cancer patients. Tumors were minced into small fragments (1-3 mm3) and plated in high dose IL-2. After 4 weeks, expanded TIL were phenotyped by flow cytometry and tested for tumor reactivity by IFN-gamma production after co-culture of TIL with autologous tumor digest. IFN-gamma levels were determined by ELISA. Reactive TIL were expanded using a rapid expansion protocol (REP).

Results: The mean expansion of TIL per fragment was 1.96 × 106. From 20 primary tumors, seven were contaminated and discarded. TIL were successfully expanded from 11/13 (85%) evaluable tumors. The phenotype of expanded TIL consisted of CD3− CD56+ NK cells and CD3+ T cells. Tumor-specific reactivity was analyzed for seven samples. TIL expanded from three (43%) tumors were predominantly CD8+ and were reactive against autologous tumor as determined by IFN-gamma ELISA. Expansion of TIL during REP resulted in an average 600-fold increase in cell numbers (range of 61 - 1,774 fold) and led to the depletion of NK cells and an increase of CD3+ T cells.

Conclusions: In this study, we have demonstrated the feasibility of growing tumor-reactive TIL from head and neck tumors. This study raises the potential for the implementation of ACT with TIL for the treatment of head and neck cancer patients.

Citation Format: Luz Nagle, Amy Mackay Weber, MacLean Hall, Matthew Beatty, J. Trad Wadsworth, Caitlin McMullen, Krupal Patel, Kathryn Vorwald, Christine Chung, Shari Pilon-Thomas. Expansion of tumor-specific tumor-infiltrating lymphocytes (TIL) from head and neck tumors [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 2178.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Optical coherence tomography-guided laser marking with tethered capsule endomicroscopy in unsedated patients

Tethered capsule endomicroscopy (TCE) is an emerging screening technology that comprehensively obtains microstructural OCT images of the gastrointestinal (GI) tract in unsedated patients. To advance clinical adoption of this imaging technique, it will be important to validate TCE images with co-localized histology, the current diagnostic gold standard. One method for co-localizing OCT images with histology is image-targeted laser marking, which has previously been implemented using a driveshaft-based, balloon OCT catheter, deployed during endoscopy. In this paper, we present a TCE device that scans and targets the imaging beam using a low-cost stepper motor that is integrated inside the capsule. In combination with a 4-laser-diode, high power 1430/1450 nm marking laser system (800 mW on the sample and 1s pulse duration), this technology generated clearly visible marks, with a spatial targeting accuracy of better than 0.5 mm. A laser safety study was done on swine esophagus ex vivo, showing that these exposure parameters did not alter the submucosa, with a large, 4-5x safety margin. The technology was demonstrated in living human subjects and shown to be effective for co-localizing OCT TCE images to biopsies obtained during subsequent endoscopy.

Expansion of tumor infiltrating lymphocytes (TIL) from bladder cancer

Advanced bladder cancer patients have limited therapeutic options resulting in a median overall survival (OS) between 12 and 15 months. Adoptive cell therapy (ACT) using tumor infiltrating lymphocytes (TIL) has been used successfully in treating patients with metastatic melanoma, resulting in a median OS of 52 months. In this study, we investigated the feasibility of expanding TIL from the tumors of bladder cancer patients. Primary bladder tumors and lymph node (LN) metastases were collected. Tumor specimens were minced into fragments, placed in individual wells of a 24-well plate, and propagated in high dose IL-2 for four weeks. Expanded TIL were phenotyped by flow cytometry and anti-tumor reactivity was assessed after co-culture with autologous tumor digest and IFN-gamma ELISA. Of the 28 transitional cell bladder or LN tumors collected, 14/20 (70%) primary tumors and all of the LN metastases demonstrated TIL expansion. Expanded TIL were predominantly CD3⁺ (median 63%, range 10-87%) with a median of 30% CD8 + T cells (range 5-70%). TIL secreted IFN-gamma in response to autologous tumor. Addition of agonisitic 4-1BB antibody improved TIL expansion from primary bladder tumors regardless of pre-treatment with chemotherapy. This study establishes the practical first step towards an autologous TIL therapy process for therapeutic testing in patients with bladder cancer.

Cereblon, a molecular target of lenalidomide (IMiDs), negatively regulates T cell activation (IRM7P.715)

Thalidomide analogs classified as immunomodulatory drugs (IMiDs) are rapidly emerging T-cell stimulants for the treatment of cancer. Cereblon, an E3-Ub ligase receptor with no known immune regulatory function, is the first identified target of IMiDs. The drug is hypothesized to have antagonistic properties by interfering with substrate recruitment to the thalidomide-binding domain in cereblon, and agonistic activity through an exposed ring that may recruit new proteins to the Ub complex. To explore this further at the molecular level, we studied immune regulation in cereblon deficient mice (crbn-/-), which exhibited an expanded white blood cell and neutrophil compartment, and higher numbers of peripheral and splenic lymphocytes. Mature crbn-/- T cells were capable of proliferation and IL-2 production following CD3 ligation in the absence of CD28 co-ligation. This positively associates with proximal phosphorylation events including pZap70, pAKT, pro-survival Bcl-XL and Bcl-2 protein expression, and corresponds with decreased pro-apoptotic proteins Bim, Bad, and Bax. Consistent with this data in a lethal graft-versus-host (GVHD) model, MHC-class I mismatched T cells from crbn-/- mice showed shortened post-transplant survival, greater weight-loss, and higher IFN-γ compared to transplanted wild-type T-cells. These data suggest that native targets of cereblon restrain the activation threshold of T-cells and that IMiD-associated blockade of cereblon leads to T-cell potentiation.

A behaviorally selective class of thiophene-containing benzodiazepine receptor ligands

In a continued effort to probe the role of the aromatic rings in classical 1,4-benzodiazepine (BDZ) ligand pharmacology, a series of new thiophene-containing benzodiazepine receptor (BDZR) ligands were synthesized. As a first step in determining the binding profile and selectivity to BDZR functional subtypes, the affinities in two central nervous system (CNS) regions, cerebellum, in which a single 'Type I' BDZR could be labeled; and spinal cord, in which we have previously demonstrated some receptor heterogeneity, were determined. These compounds were also assessed for their compliance with a recently developed three dimensional pharmacophore for recognition and activation of the 'Type I' BDZR, using the techniques of computational chemistry. The computations showed all ligands synthesized fulfilled the minimum requirements for recognition, further validating the current pharmacophore. Using the criteria for activation, the new ligands were all predicted to be agonists at the cerebellar 'Type I' BDZR. Since the compounds showed reasonable affinity, the behavioral profile of one of them at five in vivo endpoints was determined. This compound demonstrated more behavioral selectivity than the typical 1,4-BDZ ligand. While they fulfilled the requirements for agonist activity at the 'Type I' BDZR, these ligands showed significantly greater delocalization in the electron density distribution in the lowest unoccupied molecular orbital (LUMO), so that either aromatic ring could serve as an electron accepting site, not just the one comparable to the more classical BDZR agonist, flunitrazepam. It is possible that the ability of the second ring in the tested compound (5a) to also function as an electron acceptor can affect the recognition and activation of other receptor types leading to the more discriminate behavioral profile of this thiophene analog compared to flunitrazepam.

Cholesterol interactions with tetracosenoic acid phospholipids in model cell membranes: role of the double-bond position

The synthesis and thermotropic properties of 1,2-di-(9Z)-9-tetracosenoylphosphatidylcholine [delta 9-PC(24:1,24:1), 1], 1,2-di-(5Z)-5-tetracosenoylphosphatidylcholine [delta 5-PC(24:1,24:1), 2], and 1,2-di-(15Z)-15- tetracosenoylphosphatidylcholine [delta 15-PC(24:1,24:1), 3] are reported. Liposomes prepared from these phospholipids differ from those of the natural sponge phospholipids, 1,2-di-(5Z,9Z)-5,9-hexacosadienoylphosphatidylcholine (4a) and the corresponding ethanolamine (4b), both of which virtually exclude cholesterol from their bilayers. The behavior of 1 and 2 is similar to that of 1,2-di-(6Z,9Z)-6,9-hexacosadienoylphosphatidylcholine (5), which exhibits a partial molecular interaction with cholesterol. In the case of 3, cholesterol appears to interact with the saturated acyl chain regions of this phospholipid in a manner similar to that of its interaction with DPPC acyl chains. This study delineates the effect of the double-bond location in long fatty acyl chains of phospholipids on their interactions with cholesterol.