Human In Vitro Suppression as Screening Tool for the Recognition of an Early State of Immune Imbalance
Summary
Tregs are potent suppressors of the immune system. There is a lack of unique surface markers to define them, hence, definitions of Tregs are primarily functional. Here we describe an optimized in vitro assay capable of identifying immune imbalance in subjects at risk to develop T1D.
Abstract
Regulatory T cells (Tregs) are critical mediators of immune tolerance to self-antigens. In addition, they are crucial regulators of the immune response following an infection. Despite efforts to identify unique surface marker on Tregs, the only unique feature is their ability to suppress the proliferation and function of effector T cells. While it is clear that only in vitro assays can be used in assessing human Treg function, this becomes problematic when assessing the results from cross-sectional studies where healthy cells and cells isolated from subjects with autoimmune diseases (like Type 1 Diabetes-T1D) need to be compared. There is a great variability among laboratories in the number and type of responder T cells, nature and strength of stimulation, Treg:responder ratios and the number and type of antigen-presenting cells (APC) used in human in vitro suppression assays. This variability makes comparison between studies measuring Treg function difficult. The Treg field needs a standardized suppression assay that will work well with both healthy subjects and those with autoimmune diseases. We have developed an in vitro suppression assay that shows very little intra-assay variability in the stimulation of T cells isolated from healthy volunteers compared to subjects with underlying autoimmune destruction of pancreatic β-cells. The main goal of this piece is to describe an in vitro human suppression assay that allows comparison between different subject groups. Additionally, this assay has the potential to delineate a small loss in nTreg function and anticipate further loss in the future, thus identifying subjects who could benefit from preventive immunomodulatory therapy1. Below, we provide thorough description of the steps involved in this procedure. We hope to contribute to the standardization of the in vitro suppression assay used to measure Treg function. In addition, we offer this assay as a tool to recognize an early state of immune imbalance and a potential functional biomarker for T1D.
Protocol
Discussion
As the only unique feature to Tregs, suppressive function should be tested reliably and uniformly between subjects at different phases of disease development within the same and between different studies. We offer details of the suppression assay developed in our laboratory as our contribution to the standardization of this assay. In our extensive optimization study, we have determined that T cell stimulation with anti-human CD3-coated beads (UCHT1 clone, in concentration of 1μg/ml (as opposed to commercially availabl…
Declarações
The authors have nothing to disclose.
Acknowledgements
This study was supported by Max McGee National Research Center for Juvenile Diabetesat Medical College of Wisconsin and Children’s Research Institute of Wisconsin. The funders had no role in study design, data collection and analysis, or preparation of the manuscript.
Materials
| Name of the reagent or instrument | Company | Catalogue number | Comments (optional) |
|---|---|---|---|
| Ficoll-Paque PLUS | Amersham Pharmacia Biotech | 17-1440-03 | |
| DPBS-1X | Gibco | 14190-144 | |
| Trypan Blue | Invitrogen | 15250-061 | |
| anti-CD4 microbeads | Miltenyi | 130-045-101 | |
| Pre-separation filters | Miltenyi | 130-041-407 | |
| LS column | Miltenyi | 130-042-401 | |
| EDTA | Invitrogen | 15575-020 | |
| BSA | Sigma-Aldrich | B4287 | |
| Anti-human CD4-APCCy7 (clone RPA-T4) | BD Pharmingen | 557852 | |
| Anti-human CD25-PE (clone M-A251; IL-2Rα) | BD Pharmingen | 555432 | |
| Anti-human CD8-FITC (clone RPA-T8) | BD Pharmingen | 555366 | |
| Anti-human CD14-FITC (clone M5E2; LPS receptor) | BD Pharmingen | 555397 | |
| Anti-human CD32-FITC (clone FLI8.26; FcγR-type II) | BD Pharmingen | 555448 | |
| Anti-human CD116-FITC (clone M5D12; GM-CSFRα chain) | BD Pharmingen | 554532 | |
| Dynalbeads M-450 tosylactivated | Invitrogen | 140-13 | |
| Anti-human CD3 | Ancell | 144-024 | |
| Buffer1 | Homemade | 0.1M Na2B4O7 pH7.6 | |
| Buffer2 | Homemade | PBS/2mM EDTA/ 0.1% BSA pH7.4 | |
| Buffer3 | Homemade | 0.2M Tris/0.1% BSA pH8.5 | |
| Complete RPMI media | Homemade | RPMI 1640 media 2 mM L-glutamine 5 mM HEPES 100 U/μg/ml peni/strept 0.5 mM sodium pyruvate | |
| [3H] thymidine | Perkin Elmer | NET027Z005MC | |
| human pooled AB serum | Atlanta Biologicals | S40110 | |
| Multiscreen harvest plate | Millipore | MAHFC1H60 | |
| Microscint 20 | Perkin Elmer | 6013621 |
Referências
- Barge, A., Cravotto, G., Gianolio, E., Fedeli, F. How to determine free Gd and free ligand in solution of Gd chelates. A technical note. Contrast Med. Mol. Imaging. 1, 184-188 (2006).
- Nagaraja, T. N., Croxen, R. L., Panda, S., Knight, R. A., Keenan, K. A., Brown, S. L., Fenstermacher, J. D., Ewing, J. R. Application of arsenazo III in the preparation and characterization of an albumin-linked, gadolinium-based macromolecular magnetic resonance contrast agent. J. Neurosci. Methods. 157, 238-245 (2006).
- Supkowski, R. M., Horrocks, W. D. On the determination of the number of water molecules, q, coordinated to europium(III) ions in solution from luminescence decay lifetimes. Inorg. Chim. Acta. 340, 44-48 (2002).
- Menjoge, A. R., Kannan, R. M., Tomalia, D. A. Dendrimer-based drug and imaging conjugates: design considerations for nanomedical applications. Drug Discovery Today. 15, 171-185 (2010).
- Que, E. L., Chang, C. J. Responsive magnetic resonance imaging contrast agents as chemical sensors for metals in biology and medicine. Chem. Soc. Rev. 39, 51-60 (2010).
- Uppal, R., Caravan, P. Targeted probes for cardiovascular MR imaging. Future Med. Chem. 2, 451-470 (2010).
- Major, J. L., Meade, T. J. B. i. o. r. e. s. p. o. n. s. i. v. e. Bioresponsive, cell-penetrating, and multimeric MR contrast agents. Acc. Chem. Res. 42, 893-903 (2009).
- Datta, A., Raymond, K. N. Gd-hydroxypyridinone (HOPO)-based high-relaxivity magnetic resonance imaging (MRI) contrast agents. Acc. Chem. Res. 42, 938-947 (2009).
- Leôn-Rodríguez, L. M. D., Lubag, A. J. M., Malloy, C. R., Martinez, G. V., Gillies, R. J., Sherry, A. D. Responsive MRI agents for sensing metabolism in vivo. Acc. Chem. Res. 42, 948-957 (2009).
- Castelli, D. D., Gianolio, E., Crich, S. G., Terreno, E., Aime, S. Metal containing nanosized systems for MR-molecular imaging applications. Coord. Chem. Rev. 252, 2424-2443 (2008).
- Caravan, P., Ellison, J. J., McMurry, T. J., Lauffer, R. B. Gadolinium(III) chelates as MRI contrast agents: structure, dynamics, and applications. Chem. Rev. 99, 2293-2352 (1999).
- Lauffer, R. B. Paramagnetic metal complexes as water proton relaxation agents for NMR imaging: theory and design. Chem. Rev. 87, 901-927 (1987).
- Yoo, B., Pagel, . An overview of responsive MRI contrast agents for molecular imaging. Front. Biosci. 13, 1733-1752 (2008).
- Pandya, S., Yu, J., Parker, D. Engineering emissive europium and terbium complexes for molecular imaging and sensing. Dalton Trans. 23, 2757-2766 (2006).
- Nwe, K., Xu, H., Regino, C. A. S., Bernardo, M., Ileva, L., Riffle, L., Wong, K. J., Brechbiel, M. W. A new approach in the preparation of dendrimer-based bifunctional diethylenetriaminepentaacetic acid MR contrast agent derivatives. Bioconjugate Chem. 20, 1412-1418 (2009).
- Nwe, K., Bernardo, M., Regino, C. A. S., Williams, M., Brechbiel, M. W. Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates. Bioorg. Med. Chem. 18, 5925-5931 (2010).
- Caravan, P., Das, B., Deng, Q., Dumas, S., Jacques, V., Koerner, S. K., Kolodziej, A., Looby, R. J., Sun, W. -. C., Zhang, Z. A lysine walk to high relaxivity collagen-targeted MRI contrast agents. Chem. Commun. , 430-432 (2009).
- Leôn-Rodríguez, L. M. D., Kovacs, Z. The synthesis and chelation chemistry of DOTA-peptide conjugates. Bioconjugate Chem. 19, 391-402 (2008).
- Boswell, C. A., Eck, P. K., Regino, C. A. S., Bernardo, M., Wong, K. J., Milenic, D. E., Choyke, P. L., Brechbiel, M. W. Synthesis, characterization, and biological evaluation of integrin αVβ3-targeted PAMAM dendrimers. Mol. Pharm. 5, 527-539 (2008).
