Published: October 2nd, 2018
The goal of the protocol is to show longitudinal intravital real-time tracking of thymocytes by laser scanning microscopy in thymic implants in the anterior chamber of the mouse eye. The transparency of the cornea and vascularization of the graft allows for continuously recording progenitor cell recruitment and mature T-cell egress.
The purpose of the method being presented is to show, for the first time, the transplant of newborn thymi into the anterior eye chamber of isogenic adult mice for in vivo longitudinal real-time monitoring of thymocytes´ dynamics within a vascularized thymus segment. Following the transplantation, laser scanning microscopy (LSM) through the cornea allows in vivo noninvasive repeated imaging at cellular resolution level. Importantly, the approach adds to previous intravital T-cell maturation imaging models the possibility for continuous progenitor cell recruitment and mature T-cell egress recordings in the same animal. Additional advantages of the system are the transparency of the grafted area, permitting macroscopic rapid monitoring of the implanted tissue, and the accessibility to the implant allowing for localized in addition to systemic treatments. The main limitation being the volume of the tissue that fits in the reduced space of the eye chamber which demands for lobe trimming. Organ integrity is maximized by dissecting thymus lobes in patterns previously shown to be functional for mature T-cell production. The technique is potentially suited to interrogate a milieu of medically relevant questions related to thymus function that include autoimmunity, immunodeficiency and central tolerance; processes which remain mechanistically poorly defined. The fine dissection of mechanisms guiding thymocyte migration, differentiation and selection should lead to novel therapeutic strategies targeting developing T cells.
Intrathymic T-cell differentiation and T-cell subpopulation selection constitute key processes for the development and maintenance of cell-mediated immunity in vertebrates1. This process involves a complex sequence of tightly organized events including the recruitment of progenitors from bloodstream, cell proliferation and migration, differential expression of membrane proteins, and massive programmed cell death for subsets selection. The result is the release of mature T-cells reactive to an ample spectrum of foreign antigens while displaying minimized responses to self-peptides, which end-up colonizing the peripheral lymphoid organs of the in....
The Institutional Animal Care and Use Committee (IACUC) of the University of Miami approved all the experiments according to IACUC guidelines.
1. Isolation and Trimming of Newborn Thymi
Thymus from newborn mice were isolated from B6.Cg-Tg(CAG-DsRed*MST)1Nagy/Jas mice as described in this protocol (Steps 1.1-1.9). In these transgenic mice, the chicken beta actin promoter directs the expression of the red fluorescent protein variant DsRed. MST under the influence of the cytomegalovirus (CMV) immediate early enhancer facilitating the tracking of implants.
To prevent tissue rejection, isogenic individuals .......
Due to the importance of the T-cell maturation process for individual immune competency4 and the presumed impact of precursor cell dynamics on mature T-cells produced by the thymus2,3, extensive efforts have been invested to develop alternatives to the classical fixed tissue snapshot approach.
Although tissue slices and other explants are clearly superior in reproducing tissue architecture than monolayers or agg.......
This work was supported by NIH grants R56DK084321 (AC), R01DK084321 (AC), R01DK111538 (AC), R01DK113093 (AC), and R21ES025673 (AC), and by the BEST/2015/043 grant (Consellería de Educació, cultura i esport, Generalitat valenciana, Valencia, Spain) (EO). Authors thank the SENT team at the Universidad Católica de Valencia San Vicente Mártir, Valencia, Spain and Alberto Hernandez at Centro de Investigación Príncipe Felipe, Valencia, Spain for their help with video filming and editing.....
|Isofluorane vaporizer w/isofluorane
|Kent Scientific Corp
|Dissecting scope w/light source
|Fine dissection forceps
|Medium dissection forceps
|Curved tip fine dissection forceps
|40 mm 18G needles
|Disposable transfer pipette
|Heat pad and heat lamp
|Kent Scientific Corp
|60 mm sterile dish
|Sterile 1x PBS pH(7,4)
|Drugs for pain management
|Saline solution or Viscotears
|TCS SP5 II
|Laminar flow hood
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