Cerebrospinal Fluid Dendritic Cells Infiltrate the Brain Parenchyma and Target the Cervical Lymph Nodes under Neuroinflammatory Conditions
Figure 8
CSF-circulating DCs target the CLNs.
In parallel experiments, DCs labeled with the cytoplasmic fluorescent marker CFSE were injected into the left lateral ventricle of control rats (n = 7) or EAE rats (n = 8) at the clinical peak of disease (day 12 post-immunization). Rats were then sacrificed on day 1 (d1) or 8 (d8) following injections. The cervical lymph nodes (CLNs) and axillary lymph nodes (ALN) were assessed by FACS analysis for the presence of CFSE+ cells. The level of autofluorescence was established on cells obtained from the CLNs or ALNs of non-injected EAE rats (n = 4) or control rats (n = 3). A–D: In injected EAE rats sacrificed on day 1 post-injection (n = 4), we found that 2.26+/−0.11% CFSE+ cells could be detected in the CLNs as compared to 1.37+/−0.03% in the axillary lymph nodes (p = 0.0202, Mann and Whitney test)(A). However, in injected EAE rats sacrificed on day 8 post-injection (n = 4), the percentage of CFSE+ cells was not statistically different between the CLNs and the ALNs (B). Pannels C and D show representative dot plots obtained from the analysis of injected EAE rats sacrificed on day 1 post-injection. E–F: In the CLNs of injected EAE rats, a great majority of CFSE+ cells express MHC class II molecules, on day 1 post-injection (94.25+/−3.3%) or 8 post-injection (87.65+/−5.2%). A representative dot plot is shown in F. G–H: When comparing injected EAE rats to injected control rats, data showed that on day 1 post-injection, a greater pourcentage of CSFE+ cells was detectable in the CLNs of injected EAE rats as compared to injected control rats (2.26+/−0.11% vs 1.49+/−0.13% in injected EAE and injected control rats respectively, p = 0.0339, Mann and Whitney test)(G). This difference did not reach significance on day 8 post-injection (1.71+/−0.03% vs 1.66+/−0.13% in injected EAE and injected control rats respectively) (H). *: p<0.05, NS: not significant.