Ocular Mucosal CD11b+ and CD103+ Mouse Dendritic Cells under Normal Conditions and in Allergic Immune Responses

Abstract

Steady state dendritic cells (DC) found in non-lymphoid tissue sites under normal physiologic conditions play a pivotal role in triggering T cell responses upon immune provocation. CD11b+ and CD103+ DC have received considerable attention in this regard. However, still unknown is whether such CD11b+ and CD103+ DC even exist in the ocular mucosa, and if so, what functions they have in shaping immune responses. We herein identified in the ocular mucosa of normal wild-type (WT) and Flt3-/- mice the presence of a CD11b+ DC (i.e., CD11c+ MHCII+ CD11b+ CD103- F4/80+ Sirp-a+). CD103+ DC (i.e. CD11c+ MHCII+ CD11b low CD103+ CD8a+ DEC205+ Langerin+) were also present in WT, but not in Flt3-/- mice. These CD103+ DC expressed high levels of Id2 and Flt3 mRNA; whereas CD11b+ DC expressed high Irf4, Csfr, and Cx3cr1 mRNA. Additionally, the functions of these DC differed in response to allergic immune provocation. This was assessed utilizing a previously validated model, which includes transferring specific populations of exogenous DC into the ocular mucosa of ovalbumin (OVA)/alum-primed mice. Interestingly, in such mice, topical OVA instillation following engraftment of exogenous CD11b+ DC led to dominant allergic T cell responses and clinical signs of ocular allergy relative to those engrafted with CD103+ DC. Thus, although CD11b+ and CD103+ DC are both present in the normal ocular mucosa, the CD11b+ DC subset plays a dominant role in a mouse model of ocular allergy.

Involvement of Corneal Lymphangiogenesis in a Mouse Model of Allergic Eye Disease

“…[37][38][39] Briefly, each immunization consisted of 10 lg of ovalbumin (OVA; Sigma-Aldrich Corp., St. Louis, MO, USA), 1 mg of aluminum hydroxide (Sigma-Aldrich Corp.), and 300 ng of pertussis toxin (SigmaAldrich Corp.), which were thoroughly mixed in 100 lL of sterile Hank's balanced salt solution (HBSS). Immunization was administered once via IP route, and mice were subsequently rested for 2 weeks.…”

“…[37][38][39] Briefly, scoring was performed 20 minutes post challenge and done once daily for at least 7 days. Mice were examined biomicroscopically based on four independent parameters, which include: (1) lid edema, (2) tearing/discharge, (3) chemosis, and (4) hyperemia.…”

“…38 Briefly, BM cells were collected from femurs and tibiae of freshly euthanized naïve C57BL/6 mice and were seeded at 2 3 10^5/mL in Roswell Park Memorial Institute (RPMI) 1640 supplemented with 10% fetal bovine serum (FBS), 1% penicillin/streptomycin, and 20 ng/mL of mouse GM-CSF (Biolegend, San Diego, CA, USA). Medium was changed on day 4, and nonadherent and loosely adherent cells were collected on day 7.…”

“…37,38 Bone marrow-derived dendritic cells were pulsed with OVA (0.2 mg/mL) overnight and thoroughly washed, as previously described. 37,38 Each mouse was injected with 5 3 10^4 CD45.1 BMDCs in sterile HBSS.…”

“…We addressed this herein using a well-established mouse model of Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783 AED, which is induced by allergen sensitization and subsequent chronic allergen exposure. [37][38][39] This leads to a robust eosinophil involvement 39 and sequelae consistent with chronic allergic inflammation, such as blepharitis and corneal epitheliopathy. 37 The data presented herein reveal, for the first time, the distinct involvement for corneal LA in AED, and that prevention of corneal LA via VEGF receptor (R) inhibition diminishes AED.…”