प्रतियोगी घर वापस आना Assays आंत रेखा टी सेल प्रवासन अध्ययन

Summary

प्रतियोगी घर वापस आना प्रयोगों के लिए सीधे एक माउस में दो अलग अलग सेल आबादी के प्रवासी गुण का आकलन करने की अनुमति देते हैं. यहाँ हम पूर्व vivo उत्पन्न आंत – रेखा बनाम गैर पेट रेखा टी कोशिकाओं के प्रवास की तुलना द्वारा इस प्रक्रिया का वर्णन.

Abstract

In order to exert their function lymphocytes need to leave the blood and migrate into different tissues in the body. Lymphocyte adhesion to endothelial cells and tissue extravasation is a multistep process controlled by different adhesion molecules (homing receptors) expressed on lymphocytes and their respective ligands (addressins) displayed on endothelial cells ^{1 2}. Even though the function of these adhesion receptors can be partially studied ex vivo, the ultimate test for their physiological relevance is to assess their role during in vivo lymphocyte adhesion and migration. Two complementary strategies have been used for this purpose: intravital microscopy (IVM) and homing experiments. Although IVM has been essential to define the precise contribution of specific adhesion receptors during the adhesion cascade in real time and in different tissues, IVM is time consuming and labor intensive, it often requires the development of sophisticated surgical techniques, it needs prior isolation of homogeneous cell populations and it permits the analysis of only one tissue/organ at any given time. By contrast, competitive homing experiments allow the direct and simultaneous comparison in the migration of two (or even more) cell subsets in the same mouse and they also permit the analysis of many tissues and of a high number of cells in the same experiment.

Here we describe the classical competitive homing protocol used to determine the advantage/disadvantage of a given cell type to home to specific tissues as compared to a control cell population. We chose to illustrate the migratory properties of gut-tropic versus non gut-tropic T cells, because the intestinal mucosa is the largest body surface in contact with the external environment and it is also the extra-lymphoid tissue with the best-defined migratory requirements. Moreover, recent work has determined that the vitamin A metabolite all-trans retinoic acid (RA) is the main molecular mechanism responsible for inducing gut-specific adhesion receptors (integrin a4b7and chemokine receptor CCR9) on lymphocytes. Thus, we can readily generate large numbers of gut-tropic and non gut-tropic lymphocytes ex vivoby activating T cells in the presence or absence of RA, respectively, which can be finally used in the competitive homing experiments described here.

Protocol

पेट घर वापस आना और नियंत्रण टी कोशिकाओं के एक पूर्व vivo पीढ़ी (चित्रा 1 देखें) जंगली प्रकार चूहों से एक तिल्ली mashing द्वारा splenocytes पृथक. 5 400 x जी 'पीबीएस में कोशिकाओं निलंबन और अपकेंद्रित्र Resuspend निकालें स?…

Discussion

हालांकि घर वापस आना प्रयोगों किसी भी ऊतक में कुल सेल आबादियों के प्रवास के बारे में बहुत ही मूल्यवान जानकारी प्रदान करते हैं, यह ध्यान में रखा जाना चाहिए कि इन assays सीधे endothelial आसंजन विश्लेषण नहीं करते हैं ?…

Materials

Animals: C57BL/6mice are commonly used for T cell isolation. In addition, CD45.1 and Thy1.1 congenic strains are available through Jackson Laboratories (Bar Harbor, ME).

Culture media: IMDM (Iscove’s Modified Dulbecco’s Medium + L-Glutamine + Hepes) plus 10% heat-inactivated FBS (Fetal Bovine Serum, low endotoxin, Gibco®, Invitrogen, Carlsbad, CA) supplemented with 100 U/ml penicillin, 100 mg/ml streptomycin (HyClone Antibiotics, Waltham, MA), 0.5 mg/ml fungizone/amphotericin B (Gibco), and 50 mM b-mercaptoethanol.

ACK Red Blood Cell Lysis buffer(RBC, 10 mM KHCO₃, 150 mM NH₄Cl, 0.1 mM EDTA, pH 8.0), adjust to pH 7.2-7.4 and store at room temperature).

PBS (Phosphate Buffered Saline, Hyclone, Waltham, MA).

Flow cytometry (FACS) media(PBS or IMDM + 2% FBS + 5 mM EDTA). When staining using Selectin-Fc chimeras, media with 2 mM Ca⁺⁺ should be used in all steps (including FACS acquisition). IMDM is recommended in this case.

T cell labeling and adoptive transfer: CFSE(carboxyfluorescein diacetate, succinimidyl ester), CMTMR ((5-(and-6)-(((4-chloromethyl)benzoyl)amino) tetramethylrhodamine) from Molecular Probes®, Invitrogen, Carlsbad, CA). 1000 x stocks should be made in DMSO (5 mM CFSE, 20 mM CMTMR) and stored at -20°C.

Polyclonal T cell activation: 24-well or 96-well plates (tissue-culture treated, polystyrene, flat-bottom with lid, BD Falcon, Franklin Lakes, NJ) are incubated for 2 hours at 37°C with 50 ml PBS, respectively, containing anti-CD3 plus anti-CD28 antibodies (10 mg/mL each). Then, culture plates are washed twice with PBS and used immediately for T cell culture. Alternatively, Dynabeads coated with anti-CD3/anti-CD28 (Dynal, Invitrogen, Carlsbad, CA) can be used for T cell activation instead of plate-bound antibodies.

Flow cytometry (FACS) staining: Polyclonal activation: CD3 (1452C11), CD28 (37.51). Lineage mAb: CD4 (L3T4), CD8a (Ly-2), Thy1.2 (CD90.2/53-1.2), CD45.2 (104). Gut-homing receptors: purified CCR9 (CD199/eBioCW-1.2, eBioscience, San Diego, CA), a4b7(LPAM-1/DATK3), isotype control (IgG2a, k). Skin-homing receptors: P-selectin-Fc (Purified Mouse P-Selectin – IgG Fusion Protein, BD Pharmingen, San Jose, CA), E-selectin-Fc (Recombinant Mouse E-Selectin/Fc Chimera, R&D Systems, Minneapolis, MN) plus corresponding secondary reagent goat F(ab’)2 anti-human IgG R-PE (Invitrogen, Carlsbad, CA).

All-trans retinoic acid(Sigma, St. Louis, MO)is resuspended in absolute ethanol or DMSO using a yellow bulb or an indirect source of light during the preparation. Store aliquots in glass vials at -80°C and protected from light at all times. Synthetic RAR-agonists: Am80(Wako Chemicals, Richmond, VA).