Abstract Several naturally occurring anti-insulin CD4 T cells were isolated from islet infiltrates of NOD mice. In accordance with the results of others, these T cells recognized the segment of the β-chain from residues 9–23. Peptides encompassing the B:(9–23) sequence bound weakly to I-Ag7 in two main contiguous registers in which two residues at the carboxyl end, P20Gly and P21Glu, influenced binding and T cell reactivity. Naturally occurring insulin-reactive T cells exhibited differing reactivities with the carboxyl-terminal amino acids, although various single residue changes in either the flanks or the core segments affected T cell responses. The insulin peptides represent another example of a weak MHC-binding ligand that is highly immunogenic, giving rise to distinct populations of autoimmune T cells.
Mutations in the gene for the transcription factor hepatocyte nuclear factor (HNF) 1alpha cause maturity-onset diabetes of the young (MODY) 3, a form of diabetes that results from defects in insulin secretion. Since the nature of these defects has not been defined, we compared insulin secretory function in heterozygous [HNF-1alpha (+/-)] or homozygous [HNF-1alpha (-/-)] mice with null mutations in the HNF-1alpha gene with their wild-type littermates [HNF-1alpha (+/+)]. Blood glucose concentrations were similar in HNF-1alpha (+/+) and (+/-) mice (7.8+/-0.2 and 7.9+/-0.3 mM), but were significantly higher in the HNF-1alpha (-/-) mice (13.1+/-0.7 mM, P < 0.001). Insulin secretory responses to glucose and arginine in the perfused pancreas and perifused islets from HNF-1alpha (-/-) mice were < 15% of the values in the other two groups and were associated with similar reductions in intracellular Ca2+ responses. These defects were not due to a decrease in glucokinase or insulin gene transcription. beta cell mass adjusted for body weight was not reduced in the (-/-) animals, although pancreatic insulin content adjusted for pancreas weight was slightly lower (0.06+/-0.01 vs. 0.10+/-0.01 microg/mg, P < 0.01) than in the (+/+) animals. In summary, a null mutation in the HNF-1alpha gene in homozygous mice leads to diabetes due to alterations in the pathways that regulate beta cell responses to secretagogues including glucose and arginine. These results provide further evidence in support of a key role for HNF-1alpha in the maintenance of normal beta cell function.
Weak major histocompatibility complex (MHC) binding of self-peptides has been proposed as a mechanism that may contribute to autoimmunity by allowing for escape of autoreactive T-cells from the thymus. We examined the relationship between the MHC-binding characteristics of a beta-cell antigen epitope and T-cell autoreactivity in a model of autoimmune diabetes.The binding of a proinsulin epitope, proinsulin-1(47-64) (PI-1[47-64]), to the MHC class II molecules I-A(g7) and I-A(k) was measured using purified class II molecules. T-cell reactivity to the proinsulin epitope was examined in I-A(g7+) and I-A(k+) mice.C-peptide epitopes bound very weakly to I-A(g7) molecules. However, C-peptide-reactive T-cells were induced after immunization in I-A(g7)-bearing mice (NOD and B6.g7) but not in I-A(k)-bearing mice (B10.BR and NOD.h4). T-cells reactive with the PI-1(47-64) peptide were found spontaneously in the peripancreatic lymph nodes of pre-diabetic NOD mice. These T-cells were activated by freshly isolated beta-cells in the presence of antigen-presenting cells and caused diabetes when transferred into NOD.scid mice.These data demonstrate an inverse relationship between self-peptide-MHC binding and T-cell autoreactivity for the PI-1(47-64) epitope in autoimmune diabetes.
Immuno-STATsTM are modular fusion proteins designed for the selective delivery of IL-2 to tumor-antigen specific CD8+ T cells. CUE-101, the first Immuno-STAT in clinical trials, is composed of a human leukocyte antigen (HLA) complex, HLA-A*0201, a peptide epitope derived from the HPV16 E7 protein, and 4 molecules of reduced affinity human interleukin-2 (IL-2) designed to bind, expand, and activate HPV16-specific CD8+ T cells for the treatment of HPV16+ cancers.
Methods
CUE-101-01 is a first-in-human study in patients with HLA-A*0201 genotype and HPV16+ recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). R/M HNSCC patients refractory to ≥ 1 platinum- or checkpoint-inhibitor-based systemic therapies received CUE-101 monotherapy. Patients with previously untreated PD-L1+ (CPS ≥ 1) R/M HNSCC received CUE-101 and pembrolizumab 200 mg. Therapy was administered every 3 weeks until disease progression or unacceptable toxicity. Escalating doses of CUE-101 monotherapy or in combination with pembrolizumab were evaluated, followed by expanded enrollment at the recommended phase 2 dose (RP2D). Objectives included evaluation of safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity.
Results
As of July 25, 2022, 62 patients have received CUE-101 ranging from 0.06 to 8 mg/kg/dose. The most common adverse events included fatigue (46%), anemia (24%), chills (24%), and hyponatremia (22%). In the monotherapy dose escalation portion, a MTD was not identified, and 4 mg/kg was chosen as the RP2D based on PK, PD, and preliminary clinical activity. CUE-101 dose escalation from 1 to 4 mg/kg in combination with pembrolizumab 200 mg has been completed with no DLTs observed and expansion of CUE-101 at 4 mg/kg with pembrolizumab is ongoing. PK data demonstrate dose-dependent increases in drug exposure that are sustained upon repeat dosing. PD data demonstrate selected expansion of HPV-16 E711-20-specific CD8+ T cells in the peripheral blood. Of the 19 evaluable patients treated with CUE-101 monotherapy at the RP2D of 4 mg/kg, 1 patient experienced partial response (PR) and 7 stable disease (SD) for ≥ 12 weeks. Of the 10 evaluable patients treated with CUE-101 plus pembrolizumab, 3 patients experienced PR (2 confirmed) and 2 patients SD for ≥ 12 weeks.
Conclusions
CUE-101 has a manageable safety profile and demonstrates activity alone and in combination with pembrolizumab.
Acknowledgements
The authors would like to thank all the patients who are participating in this study. The study is sponsored by Cue Biopharma, in collaboration with Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA and support from LG Chem, Ltd., Seoul, South Korea.
Trial Registration
ClinicalTrials. gov NCT03978689
Ethics Approval
This study was approved by Ethics and Institutional Review Boards (IRBs) at all study sites. IRB reference numbers: Advarra Pro00037736 (Moffitt Cancer Center), IRB 52744 (Stanford University School of Medicine), HRPO# 201905108 (Washington University School of Medicine), DF/HCC IRB# 19-374 (Massachusetts General Hospital), WIRB STUDY00008948 (University of Washington, Seattle), IRB 191714 (Vanderbilt University Medical Center Vanderbilt-Ingram Cancer Center), 2019-087 Karmanos Cancer Institute, WIRB 2000026098 (Yale Cancer Center), 2019-0578 (The University of Texas MD Anderson Cancer Center), WIRB 1908869642 (University of Arizona Cancer Center), WIRB IRB00112341(Winship Cancer Institute/Emory University), IRB 20-073 (Memorial Sloan Kettering Cancer Center), IRB00255391 (Johns Hopkins University School of Medicine), IRB(IRBMED) HUM00165746 (University of Michigan Comprehensive Cancer Center), IRB0001113 (US Oncology Inc./Affiliated Oncologists, LLC), WCG IRB00000533 (Gabrail Cancer Center), IRB000001113 (George Washington University Cancer Center).
This report details the biochemical features of natural peptides selected by the H-2Kd class I MHC molecule. In normal cell lines, the length of the naturally processed peptides ranged from 8 to 18 amino acids, although the majority were 9-mers (16% were longer than nine residues). The binding motif for the 9-mer peptides was dominated by the presence of a tyrosine at P2 and an isoleucine/leucine at the P9 position. The P2 residue contributed most towards binding; and the short peptides bound better and formed longer-lived cell surface complexes than the long peptides, which bound poorly and dissociated rapidly. The longer peptides did not exhibit this strictly defined motif. Trimming the long peptides to their shorter forms did not enhance binding and conversely, extending the 9-mer peptides did not decrease binding. The long peptides were present on the cell-surface bound to H-2Kd (Kd) and were not intermediate products of the class I MHC processing pathway. Finally, in two different TAP-deficient cells the long peptides were the dominant species, which suggested that TAP-independent pathways selected for long peptides by class I MHC molecules.
Background. Insulin-dependent diabetes mellitus (IDDM) is the second most prevalent chronic illness of children. Investigation of the treatment of IDDM is hindered by the lack of a reproducible and easily maintained non-human primate model of this disorder. Methods. We induced IDDM in 11 juvenile cynomolgus monkeys after a single (150 mg/kg) intravenous injection of streptozotocin (STZ). All diabetic monkeys were treated with insulin twice daily, based on a sliding scale. Subcutaneous vascular access ports were surgically placed in each monkey to facilitate serial blood sampling and drug administration. Allogeneic pancreatic islet cells from unrelated donors were subsequently transplanted into the mesenteric circulation of all STZ-treated monkeys. Results. Mild, transient nausea and vomiting occurred in all animals after STZ injection; however, no additional signs of toxicity occurred. Within 36 hr, all monkeys required twice daily administration of exogenous insulin to maintain a non-ketotic state. Serum C-peptide levels decreased from >1.2 ng/ml before STZ, to between 0.0 and 0.9 ng/ml after STZ, confirming islet cell destruction. Animals were maintained in an insulin-dependent state for up to 147 days without any observable clinical complications. Subcutaneous vascular access port patency was maintained up to 136 days with a single incidence of local infection. Islet cell transplantation resulted in normoglycemia within 24 hr. Serum C-peptide levels increased (range: 2-8 ng/ml) for 6-8 days in immune competent animals, and for 39-98 days after transplant in immunosuppressed monkeys. Conclusions. IDDM can be consistently induced and safely treated in juvenile cynomolgus monkeys. Chronic vascular access can be maintained with minimal supervision and complications. This model is appropriate for studies investigating potential treatments for IDDM including islet cell transplantation.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
