Purchase this article with an account.
Kazuho Isamu; Expression of TLT-2 on T cells and macrophages in corneal allografts.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6728.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
B7-H3 belongs to the B7 superfamily, a group of molecules that co-stimulate or down-modulate T-cell responses. Triggering receptor expressed on myeloid cells-like transcript-2 (TLT-2) has been identified as a B7-H3 receptor. We have previously reported that B7-H3 is constitutively expressed in ocular tissue both in normal and in graft-bearing eyes and B7-H3/TLT-2 pathway is necessary for corneal allograft survival. B7-H3/TLT-2 pathway maintains acceptance of corneal allografts by inducing allo-specific anterior chamber-associated immune deviation (ACAID) as a systemic effect and suppressing allo-reactive CD4+ T cells within the eye as a local effect. To further determine a role for B7-H3/TLT-2 pathway in the eye after corneal transplantation, we analyzed the expression and localization of TLT-2 in corneal grafts.
Normal corneas of C57BL/6 were transplanted orthotopically into the normal eyes of BALB/c mice. Allogeneic corneal graft-bearing eyes were removed from recipient. Normal BALB/c eyes mice and syngeneic corneal grafts-bearing eyes were used as controls. Expression of TLT-2 on CD4, CD8 and CD11b cells in normal eyes and in graft-bearing eyes was assessed immunohistochemically by confocal microscopy.
TLT-2 was not expressed in normal eye. TLT-2+CD11b+ cells, TLT-2+CD4+, and TLT-2+CD8+ cells were present in the corneal stroma of allografts. Numbers of TLT-2+CD4+ and TLT-2+CD8+ cells were higher in the rejected allografts and accepted allografts than in the syngeneic grafts. Numbers of TLT-2+CD4+ cells were significantly higher than that of TLT-2+CD8+ cells in the accepted allografts (**P < 0.01). Numbers of TLT-2+CD8+ cells were significantly higher in the rejected allografts than in the accepted allografts (*P < 0.05).
TLT-2 is not expressed in normal ocular tissue, but expression was seen on infiltrating macrophages and T cells after corneal allo-transplantation. Since our previous data revealed that blockade of TLT-2 accelerated corneal allograft rejection, TLT-2 expressed on macrophages and T cells infiltrating into the corneal allografts may contribute to immune regulation..
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only