Specific activated T cells regulate IL-12 production by human monocytes stimulated with Cryptococcus neoformans

Cinzia Retini, Arturo Casadevall, Donatella Pietrella, Claudia Monari, Barbara Palazzetti, Anna Vecchiarelli

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48 Scopus citations


IL-12 production mediated by a T cell-independent and/or T cell- dependent pathway was investigated in human monocytes responding to Cryptococcus neoformans. The data of this study showed that: 1) appreciable levels of IL-12 were observed when freshly isolated monocytes were exposed to acapsular C. neoformans or Candida albicans and secretion occurred within 24- 48 h of incubation; 2) monocytes alone were poor producers of IL-12 when stimulated with encapsulated C. neoformans; 3) the presence of specific anti- glucuronoxylomannan mAb favored IL-12 secretion and Fc cross-linking could play a role; 4) monocytes were able to secrete consistent levels of IL-12 when cultured with activated T cells responding to C. neoformans; 5) the maximum secretion of IL-12 was observed at 5-7 days of culture and was strongly regulated by the presence of endogenous IFN-γ; and 6) the interaction between CD40 on monocytes and CD40 ligand on activated T lymphocytes responding to C. neoformans played a critical role in IL-12 secretion. These data highlight the mechanisms of IL-12 production by human monocytes exposed to C. neoformans, indicating a possible biphasic secretion of IL-12, dependent on the direct effect of fungal insult, and characterized by consistent secretion of IL-12 that is dependent on the interaction of CD40 with the CD40 ligand expressed on activated T cells responding to C. neoformans.

Original languageEnglish (US)
Pages (from-to)1618-1623
Number of pages6
JournalJournal of Immunology
Issue number3
StatePublished - Feb 1 1999
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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