Dipti Vijayan

Publications (6) View all

• Article: Human CD1c (BDCA-1)+ myeloid dendritic cells secrete IL-10 and display an immuno-regulatory phenotype and function in response to Escherichia coli.

  Andrew J Kassianos, Melinda Y Hardy, Xinsheng Ju, Dipti Vijayan, Yitian Ding, Annelie J E Vulink, Kylie J McDonald, Sarah L Jongbloed, Robert B Wadley, Christine Wells, Derek N J Hart, Kristen J Radford
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  ABSTRACT: Human blood myeloid DCs can be subdivided into CD1c (BDCA-1)(+) and CD141 (BDCA-3)(+) subsets that display unique gene expression profiles, suggesting specialized functions. CD1c(+) DCs express TLR4 while CD141(+) DCs do not, thus predicting that these two subsets have differential capacities to respond to Escherichia coli. We isolated highly purified CD1c(+) and CD141(+) DCs and compared them to in vitro generated monocyte-derived DCs (MoDCs) following stimulation with whole E. coli. As expected, MoDCs produced high levels of the proinflammatory cytokines TNF, IL-6, and IL-12, were potent inducers of Th1 responses, and processed E. coli-derived Ag. In contrast, CD1c(+) DCs produced only low levels of TNF, IL-6, and IL-12 and instead produced high levels of the anti-inflammatory cytokine IL-10 and regulatory molecules IDO and soluble CD25. Moreover, E. coli-activated CD1c(+) DCs suppressed T-cell proliferation in an IL-10-dependent manner. Contrary to their mouse CD8(+) DC counterparts, human CD141(+) DCs did not phagocytose or process E. coli-derived Ag and failed to secrete cytokines in response to E. coli. These data demonstrate substantial differences in the nature of the response of human blood DC subsets to E. coli.
  European Journal of Immunology 06/2012; 42(6):1512-22. · 5.10 Impact Factor
• Article: Mincle polarizes human monocyte and neutrophil responses to Candida albicans.

  Dipti Vijayan, Kristen J Radford, Anthony G Beckhouse, Robert B Ashman, Christine A Wells
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  ABSTRACT: The distribution and function of the C-type lectin Mincle has not previously been investigated in human cells, although mouse models have demonstrated a non-redundant role for Mincle in the host response to fungal infections. This study identified an unusual pattern of reciprocal expression of Mincle on peripheral blood monocytes or neutrophils isolated from the same donor. Expression on monocytes was inversely correlated with phagocytosis and yeast killing, but was necessary for the induction of inflammatory cytokines in response to ex vivo Candida challenge. In contrast, Mincle expression on neutrophils was associated with phagocytic and candidacidal potential of those cells. Candida challenge upregulated Mincle expression but only in Mincle+ cells. These data highlight species-specific differences between the regulation of Mincle expression in mouse and man. Reciprocal expression of Mincle modified the candidacidal potential of monocytes or neutrophils, suggesting it may also polarize the type of host response to fungal infection.
  Immunology and Cell Biology 05/2012; 90(9):889-95. · 3.66 Impact Factor
• Article: Isolation and differentiation of monocytes-macrophages from human blood.

  Dipti Vijayan
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  ABSTRACT: The prevalence of fungal infections remains high, and it is associated with significant mortality and morbidity. Macrophages are heterogeneous population of effectors enriched in regions of Candida colonization. These cells sense Candida, and are critical in the resolution of these infections. Here, we describe how macrophages are generated in the presence of colony-stimulating factor-1 (CSF-1); an important cytokine required for the survival, proliferation and ex-vivo differentiation of monocytes to macrophages.
  Methods in molecular biology (Clifton, N.J.) 01/2012; 844:183-7.
• Source

  Available from: PubMed Central

  Article: IL-12 and related cytokines: function and regulatory implications in Candida albicans infection.

  Robert B Ashman, Dipti Vijayan, Christine A Wells
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  ABSTRACT: IL-12 is a cytokine with links to both innate and adaptive immunity systems. In mice, its deletion leads to acute susceptibility to oral infection with the yeast Candida albicans, whereas such mice are resistant to systemic disease. However, it is an essential component of the adaptive response that leads to the generation of Th1-type cytokine responses and protection against disseminated disease. This paper presents an overview of the role of IL-12 in models of systemic and mucosal infection and the possible relationships between them.
  Clinical and Developmental Immunology 01/2011; 2011:686597. · 1.84 Impact Factor
• Article: Innate Immune Recognition of Candida albicans by the c-type lectin, Mincle

  Suzanne Butcher, Kelly Jane Hitchens, Dipti Vijayan, James Anthony St John, Robert Ashman, Christine Wells
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  ABSTRACT: No Yes