Therapeutic DNA vaccine reduces schistosoma mansoni-induced tissue damage through cytokine balance and decreased migration of myofibroblasts

Immunotherapeutic Activities of a DNA Plasmid Carrying the Mycobacterial hsp65 Gene (DNAhsp65)

DNA vaccines have become relevant subject matter, and efforts for their development have been increasing due to their potential as technology platforms applicable for prophylactic and therapeutic approaches for infectious diseases and for cancer treatment, allergies, and autoimmune diseases. This review aimed to summarize current knowledge about the plasmid DNA vaccine carrying the mycobacterial hsp65 gene (DNAhsp65), which demonstrates immunomodulatory and immunoregulatory properties of both the innate and adaptive immune systems. The possible mechanisms associated with the modulation and regulatory role of DNAhsp65 in the control of various conditions is also discussed.

Soil-Transmitted Helminth Vaccines: Are We Getting Closer?

Parasitic helminths infect over one-fourth of the human population resulting in significant morbidity, and in some cases, death in endemic countries. Despite mass drug administration (MDA) to school-aged children and other control measures, helminth infections are spreading into new areas. Thus, there is a strong rationale for developing anthelminthic vaccines as cost-effective, long-term immunological control strategies, which, unlike MDA, are not haunted by the threat of emerging drug-resistant helminths nor limited by reinfection risk. Advances in vaccinology, immunology, and immunomics include the development of new tools that improve the safety, immunogenicity, and efficacy of vaccines; and some of these tools have been used in the development of helminth vaccines. The development of anthelminthic vaccines is fraught with difficulty. Multiple lifecycle stages exist each presenting stage-specific antigens. Further, helminth parasites are notorious for their ability to dampen down and regulate host immunity. One of the first significant challenges in developing any vaccine is identifying suitable candidate protective antigens. This review explores our current knowledge in lead antigen identification and reports on recent pre-clinical and clinical trials in the context of the soil-transmitted helminths Trichuris, the hookworms and Ascaris. Ultimately, a multivalent anthelminthic vaccine could become an essential tool for achieving the medium-to long-term goal of controlling, or even eliminating helminth infections.

Recent advances in Schistosoma mekongi ecology, transcriptomics and proteomics of relevance to snail control

Mekong schistosomiasis caused by Schistosoma mekongi is a public health problem that occurs along the border between southern Laos and northern Cambodia. Given its restricted distribution and low prevalence, eventual eradication via an effective control program can be expected to be successful. To achieve this goal detailed knowledge of its basic biology, molecular biology, biochemistry, and pathology is urgently required. In this regard, recent studies on transcriptome analysis of adult male and female S. mekongi worms, and proteome analysis of developmental stages have been reported and are discussed here. The biology, habitat, and distribution of the snail intermediate host Neotricula aperta, which are factors in disease transmission, are discussed in this review. These have initiated renewed interest in S. mekongi research and contributed promising data that will be utilized in the generation of effective control and prevention strategies.

Recombinant Lactobacillus casei Expressing Capsid Protein VP60 can Serve as Vaccine Against Rabbit Hemorrhagic Disease Virus in Rabbits

Rabbit hemorrhagic disease virus (RHDV) is the causative agent of rabbit hemorrhagic disease (RHD). RHD, characterized by hemorrhaging, liver necrosis, and high morbidity and mortality in rabbits and hares, causes severe economic losses in the rabbit industry worldwide. Due to the lack of an efficient in-vitro propagation system for RHDV, the current vaccine is produced via chemical inactivation of crude RHDV preparation derived from the livers of infected rabbits. Inactivated vaccines are effective for controlling RHD, but the potential problems of biosafety and animal welfare have negative effects on the application of inactivated vaccines. In this study, an oral Lactobacillus casei (L. casei) vaccine was used as an antigen delivery system to express RHDV capsid protein VP60(VP1)-eGFP fusion protein. The expression of the recombinant protein was confirmed via western blotting and immunofluorescence (IFA). Our results indicate that oral administration of this probiotic vaccine can stimulate secretory immunoglobulin A (SIgA)-based mucosal and IgG-based humoral immune responses in rabbits. The immunized rabbits were completely protected against challenge with RHDV. Our findings indicate that the L. casei expression system is a new strategy for the development of a safe and efficient vaccine against RHDV.

Combined immunization using DNA-Sm14 and DNA-Hsp65 increases CD8+ memory T cells, reduces chronic pathology and decreases egg viability during Schistosoma mansoni infection

BACKGROUND

Schistosomiasis is one of the most important neglected diseases found in developing countries and affects 249 million people worldwide. The development of an efficient vaccination strategy is essential for the control of this disease. Previous work showed partial protection induced by DNA-Sm14 against Schistosoma mansoni infection, whereas DNA-Hsp65 showed immunostimulatory properties against infectious diseases, autoimmune diseases, cancer and antifibrotic properties in an egg-induced granuloma model.

METHODS

C57BL/6 mice received 4 doses of DNA-Sm14 (100 μg/dose) and DNA-Hsp65 (100 μg/dose), simultaneously administrated, or DNA-Sm14 alone, once a week, during four weeks. Three groups were included: 1- Control (no immunization); 2- DNA-Sm14; 3- DNA-Sm14/DNA-Hsp65. Two weeks following last immunization, animals were challenged subcutaneously with 30 cercariae. Fifteen, 48 and 69 days after infection splenocytes were collected to evaluate the number of CD8+ memory T cells (CD44(high)CD62(low)) using flow cytometry. Forty-eight days after challenge adult worms were collected by portal veins perfusion and intestines were collected to analyze the intestinal egg viability. Histological, immunohistochemical and soluble quantification of collagen and α-SMA accumulation were performed on the liver.

RESULTS

In the current work, we tested a new vaccination strategy using DNA-Sm14 with DNA-Hsp65 to potentiate the protection against schistosomiasis. Combined vaccination increased the number of CD8+ memory T cells and decreased egg viability on the intestinal wall of infected mice. In addition, simultaneous vaccination with DNA-Sm14/DNA-Hsp65 reduced collagen and α-SMA accumulation during the chronic phase of granuloma formation.

CONCLUSION

Simultaneous vaccination with DNA-Sm14/DNA-Hsp65 showed an immunostimulatory potential and antifibrotic property that is associated with the reduction of tissue damage on Schistosoma mansoni experimental infection.

Inhibition of inflammatory response in LPS-induced macrophages by 9-KOTE and 13-KOTE produced by biotransformation

Lipid mediators such as the leukotrienes, resolvins and protectins have been considered excellent models for the development of new anti-inflammatory drugs, due to their high potentiality. Nevertheless, only tiny amounts are available from natural sources and they have to be prepared by total synthesis. It is known that besides chemical reagents, microorganisms can also promote fatty acid oxygenation, via enzymatic reactions. In this context, the aim of this work was to produce oxylipids analogues in structure to lipid mediators employing microbial biotransformation. To this end, α-linolenic acid (ALA) was biotransformed by the fungi Aspergillus niger into oxylipids with different levels of oxygenation within 24h or 48h. The anti-inflammatory potential of products were evaluated by means of NO and TNF-α quantification in LPS-stimulated RAW264.7 macrophage cell line which guided the isolation of the regioisomers at m/z [M-H](-) 291, 9-keto-10E,12Z,15Z-octadecatrienoic acid (9-KOTE) and 13-keto-9Z,11E,15Z-octadecatrienoic acid (13-KOTE). We showed that biotransformation represents a powerful strategy for the production of potentially interesting candidates for development of anti-inflammation therapies.

Downmodulation of peripheral MOG-specific immunity by pVAXhsp65 treatment during EAE does not reach the CNS

Most of the therapeutic strategies to control multiple sclerosis are directed to immune modulation and inflammation control. As heat shock proteins are able to induce immunoregulatory T cells, we investigated the therapeutic effect of a genetic vaccine containing the mycobacterial hsp65 gene on experimental autoimmune encephalomyelitis (EAE). Although pVAXhsp65 was immunogenic for mice with EAE and downmodulated specific cytokine induction by MOG, therapy was not able to decrease clinical severity nor to modify immunologic parameters in the CNS. These results indicate that hsp65, administered as a DNA vaccine, was not therapeutic for EAE.

Immunotherapeutic efficacy of recombinant Mycobacterium smegmatis expressing Ag85B-ESAT6 fusion protein against persistent tuberculosis infection in mice

The application of immunotherapy in combination with chemotherapy is considered an effective treatment strategy against persistent Mycobacterium tuberculosis (Mtb) infection. In this study, we constructed a novel recombinant Mycobacterium smegmatis (rMS) strain that expresses Ag85B and ESAT6 fusion protein (AE-rMS). Immunization of C57BL/6 mice with AE-rMS generated mainly Th1-type immune responses by strongly stimulating IFN-γ- and IL-2-producing splenocytes and increasing antigen-specific cytotoxic T lymphocyte (CTL) activity. To test the immunotherapeutic efficacy of AE-rMS, a persistent tuberculosis infection (PTBI) model was established via tail-vein injection of C57BL/6 mice with 1×10(4) colony forming units (CFU) of Mtb strain H37Rv in combination with concurrent chemotherapy drugs isoniazid (INH) and pyrazinamide (PZA). PTBI mice immunized with AE-rMS showed high levels of IFN-γ secreted by splenocytes and decreased bacteria loads in lung. Treatment with only the anti-tuberculosis (anti-TB) drugs RFP and INH (RI), decreased bacteria loads to low levels, with the Th1-type immune response further attenuated. Moreover, AE-rMS, when combined with RI treatment, further reduced the bacteria load as well as the pathological tissue damage in lung. Together, these results demonstrated the essential roles of AE-rMS-induced Th1-type responses, providing an effective treatment strategy by combining AE-rMS and RI for persistent TB.