C-type lectin receptors (CLRs) are an important family of pattern recognition receptors (PRR) that specifically recognize a variety of pathogens. Distinct CLRs which play a key role in the establishment and dissemination of HIV-1 infection in vivo, are expressed abundantly on DCs after different stimulations. Through analyzing CLR expression, we can evaluate the direct effect on HIV-1 infection and spread by mucosal delivery systems, providing a new model and standard for research in vitro and safety evaluation of mucosal vaccine, adjuvant and drug. Our previous work showed that vaginal lactobacilli can stimulate DCs precursors THP-1 to express Langerhans cells marker molecules, such as CD1a, CD324 and CCR6. And Langerin/CD207, as more specific and characteristic CLR for LC, can capture HIV-1 through its high-affinity binding, scavenge virus and prevent virus infection and dissemination. So, in the present study we will research the induction of expression of Langerin/CD207. The results demonstrated that L. crispatus could strongly upregulate the expression levels of Langerin/CD207, accompany with much higher endocytic activity and Th1 cytokines production. These results indicated that L. crispatus could induce THP-1 differentiate into functional LC which can prevent HIV-1 infection and dissemination in vivo through Langerin/CD207 and immune regulation. As a result, vaginal lactobacilli can serve as delivery systems of mucosal immune vaccine for further research. On this basis, we compared the effect of other 5 strains of lactobacilli on THP-1, finding that there were differences in affecting morphology, 5 kind of CLR expression, DC associated molecules and phagocytosis. These results indicate there is a need of further evaluation and screening to conclude whether the different lactobacilli are qualified candidate strains as vaccine delivery systems. In conclusion, the present study screened the lactobacilli strains which could upregulate Langerin/CD207 expression and immune regulation function on THP-1. The research established the basis for evaluating the vaginal delivery systems and further concentration on monocytes. Meanwhile it was helpful to establish appropriate evaluation system in vitro according to the mechanism of resistance to HIV infection. So we can prodetermine the effect of delivery systems alone on HIV-1infection and dissemination.
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