human c peptide elisa kit  (R&D Systems)

Journal: JCI Insight

Article Title: Modeling immune responses to autologous and allogeneic human stem cell–derived islet grafts in vivo

doi: 10.1172/jci.insight.200738

Figure Lengend Snippet: ( A and B ) Human immune system reconstitution in cohort 1 ( A ) and 2 ( B ); human chimerism is measured as the percentage of human CD45 + cells among total CD45 + cells. Each symbol represents an individual animal. In A , a hollow triangle represents an allogeneic mouse not injected with polyclonal T cells. ( C ) CD34 – nonadherent fetal liver cells reprogramming into iPSCs using Klf4, Oct3/4, Sox2, and c-Myc transcription factors delivered via the nonintegrating Sendai virus, with examples of iPSC colonies. Scale bar: 200 µm. ( D ) iPSC-to-β cell differentiations performed in the study. ( E ) Circulating C-peptide levels in autologous (cohort 1 and 2) and allogeneic grafts. In autologous cohort 1 and 2, n = 2/3 and n = 3/12 mice were injected with IAR-TCR + T cells that did not infiltrate the grafts, respectively, and n = 5/6 allogeneic mice were injected with additional in vitro activated polyclonal T cells from a mouse with the same HIS. In E , the asterisk indicates the level of significance (* P < 0.05) when comparing the percentage of circulating C-peptide in allogeneic and autologous cohort 2 at weeks 12 and 15 after β cell transplantation. ( F ) Correlation between percentage of C-peptide + cells in islet before transplant and circulating human C-peptide levels 12 and 15 weeks later. In A , B , and E , data show the mean ± SEM. In F , different groups are represented with the same symbols as E, and each symbol represents the mean of the group. Statistical analysis was performed using a mixed-effects model with Geisser-Greenhouse correction and Tukey’s post hoc test for E and a simple linear regression for F . C-1, cohort 1; C-2, cohort 2.

Article Snippet: Circulating human C-peptide was measured on 20 μL of plasma, isolated from whole blood, using the STELLUX Chemi Human C-peptide ELISA kit (Alpco).

Techniques: Injection, Virus, In Vitro, Transplantation Assay

Journal: JCI Insight

Article Title: Modeling immune responses to autologous and allogeneic human stem cell–derived islet grafts in vivo

doi: 10.1172/jci.insight.200738

Figure Lengend Snippet: ( A ) Endocrine cell populations found in the grafts, represented as percentage of total endocrine cells. ( B and C ) Comparison of C-peptide + ( B ) and C-peptide + NKX6.1 + cells ( C ) among cells found in the islet region between autologous (cohort 1, cohort 2) and allogeneic grafts. ( D ) Representative images of endocrine cell subpopulations in autologous grafts from cohort 1. Scale bar: 100 µm. ( E ) Representative images of endocrine cell subpopulations and CD57 expression in the grafts of autologous cohort 2. Scale bar: 100 µm. ( F ) Quantification of CD57 + cells in the grafts. ( G ) Quantification of CD57 expression among SC-islet cell subtypes. For D and E , markers used for analysis are indicated in the figure. In autologous cohorts 1 and 2, n = 2 and n = 3 mice were injected with IAR-TCR + T cells, respectively; n = 5 allogeneic mice were injected with additional in vitro activated polyclonal T cells (a hollow triangle represents the allogeneic mouse not injected with additional polyclonal T cells, and autologous mice injected with IAR-TCR + T cells are represented as solid circles). Mean ± SEM; 1-way ANOVA/Tukey’s post hoc test was used for B , C , and F . * P < 0.05, ** P < 0.01. C-1, cohort 1; C-2, cohort 2; SST, somatostatin.

Article Snippet: Circulating human C-peptide was measured on 20 μL of plasma, isolated from whole blood, using the STELLUX Chemi Human C-peptide ELISA kit (Alpco).

Techniques: Comparison, Expressing, Injection, In Vitro

Journal: JCI Insight

Article Title: Modeling immune responses to autologous and allogeneic human stem cell–derived islet grafts in vivo

doi: 10.1172/jci.insight.200738

Figure Lengend Snippet: ( A ) Quantification of CD45 + cell proliferation in autologous and allogeneic grafts. ( B ) Example of CD45 + cell proliferation in allogeneic grafts. Scale bar: 100 µm. ( C ) Quantification of CD3 + cell proliferation in autologous and allogeneic grafts. ( D and E ) Quantification of glucagon + α ( D ) and C-peptide + β ( E ) cell proliferation in autologous and allogeneic grafts. ( F ) Example of α and β cell proliferation in allogeneic grafts. Scale bar: 100 µm. ( G ) Example of CD45 + α and β cell proliferation in autologous grafts. n = 5 allogeneic mice were injected with additional in vitro activated polyclonal T cells (a hollow triangle represents the allogeneic mouse not injected with polyclonal T cells). Scale bar: 100 µm. Panel in F represents a lower-magnification view of the area shown in , visualized with different markers. Data shown as mean ± SEM; statistical analysis was performed with an unpaired 2-tailed t test for A and C – E . * P < 0.05. C-1, cohort 1; C-2, cohort 2.

Article Snippet: Circulating human C-peptide was measured on 20 μL of plasma, isolated from whole blood, using the STELLUX Chemi Human C-peptide ELISA kit (Alpco).

Techniques: Injection, In Vitro

Journal: bioRxiv

Article Title: BLAST: A blue light-assisted secretion toolkit tunable by reversible protein-protein interactions

doi: 10.64898/2026.03.30.715452

Figure Lengend Snippet: Secretion of therapeutic proteins with a-BLAST and d-BLAST. (a) The human preproinsulin (preproINS) construct contains a signal peptide, B-chain (yellow), C-peptide (dark gray), and A-chain (yellow), with engineered Furin cleavage sites flanking the C-peptide for maturation. To facilitate efficient processing within the Golgi apparatus, Furin protease was co-transfected with the BLAST modules. (b) Kinetic profiling of light-induced insulin secretion. Summary graphs of secreted C-peptide levels, quantified by ELISA, as a proxy for insulin secretion from a-BLAST (left) and d-BLAST (right). Both systems exhibited significant, time-dependent insulin release starting from 2 h of illumination (8.2-fold for a-BLAST, 8.4-fold for d-BLAST), reaching maximal induction at 24 h (13.8-fold for a-BLAST, 19.3-fold for d-BLAST). (c) Plasmid configurations for IL-12 secretion. Schematic of the heterodimeric cytokine IL-12-a-BLAST (left) and d-BLAST-IL-12 (right) constructs. (d) Kinetic profiling of light-induced IL-12 secretion. Summary graphs showing IL-12 secretion levels measured by ELISA. Significant secretion was observed starting at 3 h for a-BLAST (2.5-fold) and 2 h for d-BLAST (2.2-fold). At the 24 h time point, d-BLAST (4.7-fold) demonstrated a slightly higher dynamic range compared to a-BLAST (4.5-fold). Open circles represent individual measurements from three biologically independent samples. Data are presented as means ± S.D. Statistical significance was assessed using one-way ANOVA followed by Tukey’s multiple comparisons test (ns = not significant, * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001).

Article Snippet: Secreted human C-peptide levels in the supernatant were quantified using a Human C-peptide ELISA Kit (R&D Systems; Catalog #DICP00).

Techniques: Construct, Transfection, Enzyme-linked Immunosorbent Assay, Plasmid Preparation

Journal: The Journal of Clinical Endocrinology and Metabolism

Article Title: Prenatal Concentrations of Perfluoroalkyl Substances and Maternal Beta Cell Function at 7 to 9 Years of Follow-Up

doi: 10.1210/clinem/dgaf143

Figure Lengend Snippet: Percent change (95% CI) in maternal metabolic composite measures of beta cell function and insulin resistance, including (A) PI:INS ratio, (B) PI:CP ratio, (C) HOMA-IR, (D) TyG index, per doubling of second trimester plasma PFOA, PFOS, PFHxS, PFNA, PFDA, and PFUnDA concentrations. Models were adjusted for maternal age at index pregnancy, pre-pregnancy BMI, race and ethnicity, education at index pregnancy, diet quality assessment score at index pregnancy, and smoking status at follow-up. Abbreviations: CP, C-peptide; HOMA-IR, Homeostatic Model of Insulin Resistance; INS, insulin; PFDA, perfluorodecanoic acid; PFHxS, perfluorohexane sulfonic acid; PFNA, perfluorononanoic acid; PFOA, perfluorooctanoic acid; PFOS, perfluorooctanesulfonic acid; PFUnDA, perfluoroundecanoic acid; PI, proinsulin; TyG, triglyceride-glucose.

Article Snippet: C-peptide and mature human insulin concentrations were measured with C-peptide Chemiluminescence ELISA kits (#80-CPTHU-CH01, ALPCO Diagnostics, Salem, New Hampshire; RRID: AB_3665034) and Human Insulin Chemiluminescence ELISA kits (#80-INSHU-CH01, ALPCO Diagnostics, Salem, New Hampshire; RRID: AB_2894946) according to manufacturer's instructions.

Techniques: Cell Function Assay, Clinical Proteomics

Journal: The Journal of Clinical Endocrinology and Metabolism

Article Title: Prenatal Concentrations of Perfluoroalkyl Substances and Maternal Beta Cell Function at 7 to 9 Years of Follow-Up

doi: 10.1210/clinem/dgaf143

Figure Lengend Snippet: Percent change (95% CI) in fasted maternal metabolic measures 7 to 9 years later including (A) proinsulin, (B) insulin, (C) C-peptide, (D) HbA1c, (E) fasting glucose per doubling of second trimester plasma PFOA, PFOS, PFHxS, PFNA, PFDA, and PFUnDA concentrations. Models were adjusted for maternal age at index pregnancy, pre-pregnancy BMI, race and ethnicity, education at index pregnancy, diet quality assessment score at index pregnancy, and smoking status at follow-up. Abbreviations: HbA1c, hemoglobin A1c; PFDA, perfluorodecanoic acid; PFHxS, perfluorohexane sulfonic acid; PFNA, perfluorononanoic acid; PFOA, perfluorooctanoic acid; PFOS, perfluorooctanesulfonic acid; PFUnDA, perfluoroundecanoic acid.

Article Snippet: C-peptide and mature human insulin concentrations were measured with C-peptide Chemiluminescence ELISA kits (#80-CPTHU-CH01, ALPCO Diagnostics, Salem, New Hampshire; RRID: AB_3665034) and Human Insulin Chemiluminescence ELISA kits (#80-INSHU-CH01, ALPCO Diagnostics, Salem, New Hampshire; RRID: AB_2894946) according to manufacturer's instructions.

Techniques: Clinical Proteomics