A Recombinant Rabies Virus Expressing Fms-like Tyrosine Kinase 3 Ligand(Flt3L) Induces Enhanced Immunogenicity in Mice

Rabies is a zoonotic disease that still causes 59,000 human deaths each year,and rabies vaccine is the most effective way to control the disease.Our previous studies suggested that the maturation of DC plays an important role in enhancing the immunogenicity of rabies vaccine.Flt3L has been reported to own the ability to accelerate the DC maturation,therefore,in this study,a recombinant rabies virus expressing mouse Flt3L,designated as LBNSE-Flt3L,was constructed,and its immunogenicity was characterized.It was found that LBNSE-FU3L could enhance the maturation of DC both in vitro and in vivo,and significantly more TFH cells and Germinal Center B(GC B)cells were generated in mice immunized with LBNSE-FU3L than those immunized with the parent virus LBNSE.Consequently,expressing of Flt3L could elevate the level of virus-neutralizing antibodies(VNA)in immunized mice which provides a better protection from a lethal rabies virus challenge.Taken together,our study extends the potential of Flt3L as a good adjuvant to develop novel rabies vaccine by enhancing the VNA production through activating the DC—Tfh^GC B axis in immunized mice.

The equivalents of human blood and spleen dendritic cell subtypes can be generated in vitro from human CD34 ＋ stem cells in the presence of fins-like tyrosine kinase 3 ligand and thrombopoietin

Dendritic cells （DCs） are immune cells specialized to capture, process and present antigen to T cells in order to initiate an appropriate adaptive immune response. The study of mouse DC has revealed a heterogeneous population of cells that differ in their development, surface phenotype and function. The study of human blood and spleen has shown the presence of two subsets of conventional DC including the CDlb/c＋ and CD141＋CLEC9A＋ conventional DC （cDC） and a plasmacytoid DC （pDC） that is CD304＋CD123＋. Studies on these subpopulations have revealed phenotypic and functional differences that are similar to those described in the mouse. In this study, the three DC subsets have been generated in vitrofrom human CD34＋ precursors in the presence of fins-like tyrosine kinase 3 ligand （FIt3L） and thrombopoietin （TPO）. The DC subsets so generated, including the CDlb/c＋ and CLEC9A＋ cDCs and CD123 ＋ pDCs, were largely similar to their blood and spleen counterparts with respect to surface phenotype, toll-like receptor and transcription factor expression, capacity to stimulate T cells, cytokine secretion and cross-presentation of antigens. This system may be utilized to study aspects of DC development and function not possible in vivo.

A novel recombinant DNA vaccine encodingMycobacterium tuberculosis ESAT-6 and FL protects againstMycobacterium tuberculosis challenge in mice

Mycobacterium tuberculosis 6-kDa early secretory antigenic target （ESAT-6） is a dominant target antigen for cell-mediated immunity in the early phase of tuberculosis. The fms-like tyrosine kinase 3 ligand （FL） that induces potent immune response has been used as an adjuvant in vaccine development. In this study, a new recombinant plasmid （plRES-epitope-peptides-FL） encoding three T cell epitopes of ESAT-6 and FL was constructed, and the immunogenicity of the DNA vaccine was assessed in C57BL/6 mice immunized with the plasmid DNA vaccine. Additionally, a strategy of intramuscular injection with the DNA vaccine （prime） and intranasal administration of the epitope peptides （boost） was employed to induce higher immune reaction of the mice. The results showed that mice vaccinated with the recombinant plasmid DNA vaccine and boosted with the peptides not only increased the levels of Thl cytokines （IFN-γ and IL-12）, the number of IFN-γ＋ T cells and activities of cytotoxic T lymphocytes as well as IgG, but also enhanced protection against Mycobacterium tuberculosis challenge. In conclusion, these data indicate that the novel recombinant plRES-epitope-peptides-FL plasmid is a useful DNA vaccine for pre- venting Mycobacterium tuberculosis infection.

Biomarkers for Primary Sjgren's Syndrome

Primary Sjogren＇s syndrome （pSS） is a systemic autoimmune disease with exocrine gland dysfunction and multi-organ involvement. Recent progress in understanding the pathogenesis of pSS offers an opportunity to find new biomarkers for the diagnosis and assessment of disease activity. Screening noninvasive biomarkers from the saliva and tears has significant potential. The need for specific and sensitive biomarker candidates in pSS is significant. This review aims to summarize recent advances in the identification of biomarkers of Sjogren syndrome, trying to identify reliable, sensitive, and specific biomarkers that can be used to guide treatment decisions.