Population Council Research that makes a difference

Abstract

Candida albicans-induced DC activation reduces HIV amplification by DCs while increasing DC-to-T-cell spread of HIV (HTML) 
Vachot,Laurence; Williams,Vennansha G.; Bess Jr.,Julian W.; Lifson,Jeffrey D.; Robbiani,Melissa
Journal of Acquired Immune Deficiency Syndromes 48(4): 398-407
Publication date: 2008

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Dendritic cells (DCs) are central to the innate and adaptive responses needed to control pathogens, yet HIV exploits DCs to promote infection. The influence of other pathogens on DC-HIV interplay has not been extensively studied. We used Candida albicans (Candida) as a model pathogen which elicits innate DC responses that are likely important in controlling Candida by healthy immune systems. HIV did not impede Candida-specific DC activation. Candida-induced CD80 and CD83 upregulation was greater in DCs that had captured HIV, coinciding with increased amplification in presence of T cells and reduced but persistent low-level DC infection. In contrast, HIV-infected DCs matured normally in response to Candida, but this did not shut down HIV replication in DCs, and again Candida augmented HIV amplification in DC-T-cell mixtures. HIV-infected DCs secreted more IL-10 and IL-1[beta] earlier than uninfected DCs and initially induced a higher frequency of CD4+CD25+FoxP3+ T-regulatory cells in response to Candida. Elevated early IL-10 production in cocultures was evident only when azidothymidine (AZT) was included to limit T-regulatory cell infection and destruction. Therefore, HIV manipulates the DC's innate and adaptive responses to Candida to further augment HIV spread, ultimately destroying the cells needed to limit candidiasis.

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