Selective and site-specific mobilization of dermal dendritic cells and Langerhans cells by Th1- and Th2-polarizing adjuvants

Abstract

Dendritic cells (DCs) initiate and polarize adaptive immune responses toward varying functional outcomes. By means of intravital two-photon microscopy, we report that dermal dendritic cells (DDCs) and Langerhans cells (LCs) are differentially mobilized during contact sensitization and by adjuvants such as unmethylated CpG oligonucleotide (CpG) and LPS that induce T helper type 1 (Th1) responses, or papain that induces T helper type 2 (Th2) responses. In ear pinna, contact sensitization, CpG, LPS, and papain all mobilized DDCs in three distinct phases: increased motility and dendritic probing, directed migration, and entry into lymphatic vessels. During the same treatments, the adjacent LCs in ear pinna remained immotile over a 48-hr period of observation. In contrast, footpads lacked DDCs and Th1-polarizing adjuvants selectively induced a delayed mobilization of LCs after 48 hr. Th1 polarization of CD4 + T cells was independent of the immunization site, whereas ear immunization favored Th2 polarization, correlating with sitespecific DC distribution and dynamics. Our results provide an initial description of peripheral DC dynamics in response to adjuvants and imply that LC mobilization enhances a Th1 response and is not sufficient to trigger a Th2 response, whereas mobilization of DDCs alone is sufficient to trigger T-cell proliferation and to polarize initial T-cell activation toward a Th2 response.T-cell priming | two-photon microscopy | vaccine | imaging

Intradermal immunization in the ear with cholera toxin and its non‐toxic β subunit promotes efficient Th1 and Th17 differentiation dependent on migrating DCs

“…Consistent with previous reports [32], this result suggests that in our model, sustained antigen presentation (in this case, mediated by DCs that migrate from the ear and arrive at dCLNs) is crucial for inducing CD4 1 T cells to differentiate into cytokineproducing cells, even in the presence of strong adjuvants such as CT. Our experiments indicate that migrating cells that arrive after 90 min but within the first 24 h of immunization are important for T-cell differentiation. Considering the migration kinetics of skin DCs, even in the presence of adjuvants [6,7], it is very possible that in our model, dermal DCs achieve initial antigen presentation and priming, which is consistent with previous reports [12,13]. However, our results show that the number of LCs is Figure 5.…”

“…This is in contrast with a previous report where spleen DCs were activated by the CT but not by CTB [21]. It has been reported that LCs remain in the epidermis for 48 h, even in the presence of Th1-polarizing adjuvants [7]. In our experiments, 24 h after CT or CTB inoculation in the ear, the number of LCs in the epidermis was reduced, suggesting that LCs could be mobilized from the dermis at this time point in the presence of strong adjuvants such as CT.…”

“…Although Langerhans cells (LCs) have been shown to be potent APCs in vitro [3], in vivo approaches have produced conflicting data regarding their role in T-cell priming [4,5]. Dermal DCs are also migrating DCs that colonize lymph nodes more rapidly than LCs [6,7], and different roles for skin DC subsets in T-cell priming have been reported [7][8][9]. Skin immunization has yielded controversial data, with some reports supporting a Th2-type response [10,11] and others a Th1-type response [12,13].…”

Differential requirement for ROCK in dendritic cell migration within lymphatic capillaries in steady-state and inflammation

“…35,36 Therefore, to date, LVs have mainly been visualized in IVM by in vivo labeling with intracutaneously injected fluorescent antibodies. 4,37,38 However, antibody labeling is considered less optimal for IVM than endogenous expression of fluorophores; it is typically restricted to the injection site and downstream regions and could interfere with leukocyte-endothelium interactions or lead to unwanted immune activation. To bypass these potential problems, we bred mice expressing Cre-recombinase 24 with RFP reporter mice.…”

“…However, studies performed in mice to evaluate the kinetics of DC migration in response to contact sensitization have revealed that it takes much longer before the first DCs are detected in skin dLNs, and maximal numbers of migrated DCs are only reached after 24 hours. 45,46 Mobilization of dermal DCs from the interstitial space to the lymphatic vessel in response to contact sensitization was recently shown to occur within 1 hour of DC stimulation, 38 and DC transmigration into lymphatic capillaries reportedly occurs within 2 hours (Tal et al,4 Sen et al, 38 and supplemental Video 1). Thus, it is questionable whether the overall time needed for DC mobilization, transmigration, and passive intralymphatic transport by flow could explain the long time required for DC migration from skin to dLNs.…”