MV140 Mucosal Vaccine Induces Targeted Immune Response for Enhanced Clearance of Uropathogenic E. coli in Experimental Urinary Tract Infection.

MV140 is an inactivated whole-cell bacterial mucosal vaccine with proven clinical efficacy against recurrent urinary tract infections (UTIs). These infections are primarily caused by uropathogenic E. coli (UPEC) strains, which are unique in their virulence factors and remarkably diverse. MV140 contains a non-UPEC strain, suggesting that it may induce an immune response against different UPEC-induced UTIs in patients. To verify this, we experimentally evaluated the cellular and humoral responses to UTI89, a prototypical UPEC strain, in mice vaccinated with MV140, as well as the degree of protection achieved in a UPEC UTI89 model of acute cystitis. The results show that both cellular (Th1/Th17) and antibody (IgG/IgA) responses to UTI89 were induced in MV140-immunized mice. MV140 vaccination resulted in an early increased clearance of UTI89 viable bacteria in the bladder and urine following transurethral infection. This was accompanied by a highly significant increase in CD4+ T cells in the bladder and an increase in urinary neutrophils. Collectively, our results support that MV140 induces cross-reactive humoral and cellular immune responses and cross-protection against UPEC strains.

Manufacture of Mesoporous Silicon Microparticles (MSMPs) as Adjuvants for Vaccine Delivery.

The advent of computational approaches has accelerated the identification of vaccine candidates like epitope peptides. However, epitope peptides are usually very poorly immunogenic and adequate platforms are required with adjuvant capacity to verity immunogenicity and antigenicity of vaccine subunits in vivo. Silicon microparticles are being developed as potential new adjuvants for vaccine delivery due to their physicochemical properties. This chapter explains the methodology to fabricate and functionalize mesoporous silicon microparticles (MSMPs) which can be loaded with antigens of different nature, such as viral peptides, proteins, or carbohydrates, and this strategy is particularly suitable for delivery of epitopes identified by computer.

A tumor-associated heparan sulfate-related glycosaminoglycan promotes the generation of functional regulatory T cells.

Functional Tregs play a key role in tumor development and progression, representing a major barrier to anticancer immunity. The mechanisms by which Tregs are generated in cancer and the influence of the tumor microenvironment on these processes remain incompletely understood. Herein, by using NMR, chemoenzymatic structural assays and a plethora of in vitro and in vivo functional analyses, we demonstrate that the tumoral carbohydrate A10 (Ca10), a cell-surface carbohydrate derived from Ehrlich's tumor (ET) cells, is a heparan sulfate-related proteoglycan that enhances glycolysis and promotes the development of tolerogenic features in human DCs. Ca10-stimulated human DCs generate highly suppressive Tregs by mechanisms partially dependent on metabolic reprogramming, PD-L1, IL-10, and IDO. Ca10 also reprograms the differentiation of human monocytes into DCs with tolerogenic features. In solid ET-bearing mice, we found positive correlations between Ca10 serum levels, tumor size and splenic Treg numbers. Administration of isolated Ca10 also increases the proportion of splenic Tregs in tumor-free mice. Remarkably, we provide evidence supporting the presence of a circulating human Ca10 counterpart (Ca10H) and show, for the first time, that serum levels of Ca10H are increased in patients suffering from different cancer types compared to healthy individuals. Of note, these levels are higher in prostate cancer patients with bone metastases than in prostate cancer patients without metastases. Collectively, we reveal novel molecular mechanisms by which heparan sulfate-related structures associated with tumor cells promote the generation of functional Tregs in cancer. The discovery of this novel structural-functional relationship may open new avenues of research with important clinical implications in cancer treatment.

Monocyte-Derived Dendritic Cells Differentiated in the Presence of Lenalidomide Display a Semi-Mature Phenotype, Enhanced Phagocytic Capacity, and Th1 Polarization Capability.

Lenalidomide is an analog of thalidomide, with potent anticancer activity demonstrated in several hematological malignancies. It has immunomodulatory properties, being able to enhance the activation of different types of immune cells, which results in antitumor activities. Dendritic cells (DCs) are pivotal in the immune response, and different immunotherapeutic approaches targeting these cells are being developed. Since little is known about the effect of lenalidomide on DCs, the goal of the present work was to investigate the phenotype and function of human monocyte-derived DCs differentiated in the presence of lenalidomide (L-DCs). Our results showed that L-DCs display a unique phenotype, with increased cell surface expression of some maturation markers such as CD1d, CD83, CD86, and HLA-DR. This phenotype correlates with a lower expression of the E3 ubiquitin-ligase MARCH-I in L-DCs, upregulating the cell surface expression of CD86 and HLA-DR. In addition, immature L-DCs express higher amounts of DC-SIGN on the cell surface than control immature DCs. After LPS stimulation, production of IL-6 and TNF-α was severely decreased, whereas IL-12 and IL-10 secretion was dramatically upregulated in L-DCs, compared to that in the controls. Functionally, L-DCs are more effectively recognized by NKT cells in cytotoxicity experiments. Furthermore, L-DCs display higher opsonin-independent antigen uptake capability than control DCs. Mixed lymphocyte reaction experiments showed that L-DCs could stimulate naïve CD4 T-cells, polarizing them toward a predominant Th1 phenotype. In summary, DCs derived from monocytes in the presence of lenalidomide present a semi-mature phenotype, increased phagocytic capacity, reduced production of proinflammatory cytokines, and the ability to polarize T-cells toward predominant Th1-type responses; these are qualities that might be useful in the development of new immunotherapeutic treatments.