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ABSTRACTThis study analyzes the phenotype of vaginal dendritic cells (VDCs), their antigenic presentation and activation of T-cell cytokine secretion, and their protective role in a rat model of Candidavaginitis. Histological observation demonstrated a significant accumulation of OX62+VDCs in the mucosal epithelium of Candida albicans-infected rats at the third round of infection. We identified two subsets of OX62+VDCs differing in the expression of CD4 molecule in both noninfected and Candida-infected rats. The OX62+CD4+subset of VDCs displayed a lymphoid cell-like morphology and expressed the T-cell antigen CD5, whereas the OX62+CD4−VDC subset exhibited a myeloid morphology and was CD5 negative. Candidainfection resulted in VDC maturation with enhanced expression of CD80 and CD134L on both CD4+and CD4−VDC subsets at 2 and 6 weeks after Candidainfection. CD5−CD4−CD86−CD80−CD134L+VDCs from infected, but not noninfected, rats spontaneously released large amounts of interleukin-12 (IL-12) and tumor necrosis factor alpha, whereas all VDC subsets released comparable levels of IL-10 and IL-2 cytokines. Furthermore, OX62+VDCs from infected rats primed naïve CD4+T-cell proliferation and release of cytokines, including gamma interferon, IL-2, IL-6, and IL-10, in response to staphylococcal enterotoxin B stimulation in vitro. Adoptive transfer of highly purified OX62+VDCs from infected rats induced a significant acceleration of fungal clearance compared with that in rats receiving naive VDCs, suggesting a protective role of VDCs in the anti-Candidamucosal immunity. Finally, VDC-mediated protection was associated with their ability to rapidly migrate to the vaginal mucosa and lymph nodes, as assessed by adoptive transfer of OX62+VDCs labeled with 5 (and 6-)-carboxyfluorescein diacetate succinimidyl ester.

The protective roles of different lymphocyte subsets were investigated in a rat vaginal candidiasis model by adoptive transfer of vaginal lymphocytes (VL) or sorted, purified CD3(+) T cells, CD4(+) or CD8(+) T cells, or CD3(-) CD5(+) B cells from the vaginas of naïve or immune rats following three rounds of Candida albicans infection. The adoptive transfer of total VL from nonimmune animals did not alter the course of vaginal candidiasis of the recipient rats. In contrast, the animals receiving total VL or CD3(+) T cells from immune rats showed a highly significant acceleration of fungus clearance compared with animals which received nonimmune VL. The animals with vaginal CD3(-) CD5(+) B cells transferred from immune rats also had fewer Candida CFU than the controls, but fungal clearance was significantly retarded with respect to the animals administered immune T cells. Sorted, purified CD4(+) and CD8(+) vaginal T cells from immune rats were also adoptively transferred to naïve animals. Although both populations were seen to accelerate the clearance of the fungus from the vagina, CD4(+) T cells were much more effective than CD8(+) T cells. Overall, there was no difference between the antifungal effects of immune vaginal CD4(+) T cells and those achievable with the transfer of whole, immune VL. Histological observations of the vaginal tissues of rats with adoptively transferred immune T cells demonstrated a remarkable accumulation of lymphocytes in the subepithelial lamina propria and also infiltrating the mucosal epithelium. These results strongly suggest that distinct vaginal lymphocyte subsets participate in the adaptive anti-Candida immunity at the vaginal level, with the vaginal CD4(+) T cells probably playing a major role.

ABSTRACTThe signaling pathways triggered by adherence of Candida albicansto the host cells or extracellular matrix are poorly understood. We provide here evidence in C. albicansyeasts of a p105 focal adhesion kinase (Fak)-like protein (that we termed CaFak), antigenically related to the vertebrate p125Fak, and its involvement in integrin-like-mediated fungus adhesion to vitronectin (VN) and EA.hy 926 human endothelial cell line. Biochemical analysis with different anti-chicken Fak antibodies identified CaFak as a 105-kDa protein and immunofluorescence and cytofluorimetric analysis on permeabilized cells specifically stain C. albicansyeasts; moreover, confocal microscopy evidences CaFak as a cytosolic protein that colocalizes on the membrane with the integrin-like VN receptors upon yeast adhesion to VN. The protein tyrosine kinase (PTK) inhibitors genistein and herbimycin A strongly inhibited C. albicansyeast adhesion to VN and EA.hy 926 endothelial cells. Moreover, engagement of αvβ3 and αvβ5 integrin-like on C. albicanseither by specific monoclonal antibodies or upon adhesion to VN or EA.hy 926 endothelial cells stimulates CaFak tyrosine phosphorylation that is blocked by PTK inhibitor. A role for CaFak in C. albicansyeast adhesion was also supported by the failure of VN to stimulate its tyrosine phosphorylation in a C. albicansmutant showing normal levels of CaFak and VNR-like integrins but displaying reduced adhesiveness to VN and EA.hy 926 endothelial cells. Our results suggest that C. albicansFak-like protein is involved in the control of yeast cell adhesion to VN and endothelial cells.

The present study was undertaken to investigate the expression of αvβ3 and αvβ5 integrin-like vitronectin receptors (VNRs) on Candida albicansgerm tube and their involvement in its adhesion to vitronectin (VN) and human endothelial cells. By immunofluorescence and FACS analysis, several monoclonal antibodies directed against human αv or β3 integrin subunit or αvβ3 and αvβ5 heterodimers, positively stained C. albicansgerm tubes. C. albicansgerm tubes specifically adhered (45–50%) to VN and this adhesion was markedly inhibited by RGD-, but not RGE-containing peptides. Adhesion of C. albicansgerm tubes to VN was strongly inhibited by anti-αv, anti-β3 or anti-αvβ3, but not by αvβ5 monoclonal antibody. C. albicansgerm tube adhesion to VN was also inhibited by glycosaminoglycans (GAGs) such as heparin or chondroitin sulphate. Finally, we show thatC. albicansgerm tubes adhere to the human EA.hy 926 endothelial cell line. This adhesion is markedly blocked by anti-β3 monoclonal antibody, GRGDSP peptide or heparin, and is completely abolished by their combination. Overall these results indicate that C. albicansgerm tube adherence to VN and to a human endothelial cell line is mediated by αvβ3, but not by αvβ5-like integrin, and depends on GAGs which may act by regulating αvβ3 integrin-like/VN adhesive interaction.