Characterization of dendritic cells in testicular draining lymph nodes in a rat model of experimental autoimmune orchitis

Abstract

The maturation state of dendritic cells (DC) is regarded as a control point for the induction of peripheral tolerance or autoimmunity. Experimental autoimmune orchitis (EAO) serves as a model to investigate inflammatory-based testicular impairment, which ranks as a significant cause of male infertility. This work aimed to determine whether DC enrichment occurs organotypically in testicular draining lymph nodes (TLN) compared with LN draining the site of immunization (ILN) and thus contributes to the pathogenesis of autoimmune orchitis. In this regard, we quantified and characterized the DC from TLN and ILN in rats with EAO. Flow cytometric analysis showed a significant increase in the percentage of DC (OX62+) only in TLN from EAO rats compared with normal (N) and adjuvant control (C) groups. The number of DC from ILN and TLN expressing CD80, CD86 and major histocompatibility complex (MHC) II was comparable among N, C and experimental (E) groups at 30 and 50 days after the first immunization. However, TLN DC from EAO rats (50 days) showed an increase in mean fluorescence intensity for MHC II compared with N, C and E groups (30 days). The mRNA expression level of IL-10 and IL-12p35 was significantly upregulated in enriched DC fraction from TLN in EAO rats with no significant changes observed in ILN DC. The expression of IL-23p19 mRNA remained unchanged. Functional data, using proliferation assays showed that EAO-DC from TLN, but not from ILN, significantly enhanced the proliferation of naïve T cells compared with C-DC. In summary, our data suggest that the DC in TLN from orchitis rats are mature, present antigens to T cells and stimulate an autoimmune response against testicular antigens, thus causing immunological infertility.

CD4+ and CD8+ T cells producing Th1 and Th17 cytokines are involved in the pathogenesis of autoimmune orchitis

“…In this line, our previous results showing a significant increase in IL12p35 mRNA expression by the dendritic cells from rats with focal EAO (Guazzone et al 2011) provide evidence in support of a Th1 response.…”

“…The fact that none of the Teff cell subsets detected in EAO testis showed evidence of significant production of IL4 may be due to the inhibitory effect of Th1 cytokines on proliferation and cytokine production by Th2 cells (Gajewski & Fitch 1988). Although Teff cells did not express IL10, our previous results showing IL10 mRNA expression in testicular and lymph node dendritic cells of EAO but not N and C rats demonstrate that this cytokine is overexpressed under inflammatory conditions (Rival et al 2007, Guazzone et al 2011.…”

Testicular defense systems: immune privilege and innate immunity

“…In rat EAO, DCs exhibit mature properties. 46 Lymphocytes are always found in the interstitial spaces of the rat testis under physiological conditions. 47 Most testicular lymphocytes are T cells, with CD8 1 cells being more predominant and CD4 1 cells more rare.…”

Serum Autoantibodies in Mice Immunized with Syngeneic Testicular Germ Cells Alone

“…5,6,30 TH+CFA+BP-induced EAO mice sera immunologically or immunohistochemically react with germ cells behind the BTB (=spermatids and spermatocytes) and also against testicular components outside the BTB (=spermatogonia, Sertoli cells, Leydig cells and the basement membrane of the seminiferous tubules). 5,30 In contrast, TGC-induced EAO is unique in that serum autoantibodies are only against sperm and spermatids. In the present study, we found that there are some molecular differences between TGC and ES antigens that react with autoantibodies.…”

“…1,2,4 It was also revealed that macrophages, professionally antigen-presenting dendritic cells, and putative function of mast cells play an important role in development of EAO. 5,6 Classically, the immunization of mice with a testicular homogenate (TH) emulsified in complete Freund's adjuvant (CFA) followed by the intravenous injection of Bordetella pertussis (BP) is necessary for the induction of EAO, in which inflammatory cell responses are evoked in the testes, epididymis, and vas deferens. 7,8 Enzyme-linked immunosorbent assay (ELISA) analyses of the sera of TH+CFA+BP-induced EAO mice revealed that the titer of autoantibodies against epididymal spermatozoa (ES) increases compared with that in controls and that the titer of IgG is significantly higher than that of IgA or IgM.…”