Evaluation of humoral and cellular immune responses against Vibrio cholerae using oral immunization by multi-epitope-phage-based vaccine.

INTRODUCTION: Cholera is a severe gastrointestinal disease that manifests with rapid onset of diarrhea, vomiting, and high mortality rates. Due to its widespread occurrence in impoverished communities with poor water sanitation, there is an urgent demand for a cost-effective and highly efficient vaccine. Multi-epitope vaccines containing dominant immunological epitopes and adjuvant compounds have demonstrated potential in boosting the immune response. MATERIAL AND METHODS: B and T epitopes of OMPU, OMPW, TCPA, CTXA, and CTXB proteins were predicted using bioinformatics methods. Subsequently, highly antigenic multi-epitopes that are non-allergenic and non-toxic were synthesized. These multi-epitopes were then cloned into the pCOMB phagemid. A plasmid M13KO7ΔpIII containing all helper phage proteins except pIII was created to produce the recombinant phage. Female Balb/c mice were divided into three groups and immunized accordingly. The mice received the helper phage, recombinant phage or PBS via gavage feeding thrice within two weeks. Serum samples were collected before and after immunization for the ELISA test as well as evaluating immune system induction through ELISpot testing of spleen lymphocytes. RESULTS: The titer of the recombinant phage was determined to be 1011 PFU/ml. The presence of the recombinant phage was confirmed through differences in optical density between sample and control groups in the ELISA phage technique, as well as by observing transduction activity, which demonstrated successful production of a recombinant phage displaying the Vibrio multi-epitope on M13 phage pIII. ELISA results revealed significant differences in phage antibodies before and after inoculation, particularly notable in the negative control mice. Mice treated with multi-epitope phages exhibited antibodies against Vibrio cholerae lysate. Additionally, ELISpot results indicated activation of cellular immunity in mice receiving both Vibrio and helper phage. CONCLUSION: This study emphasizes the potential of multi-epitope on phage to enhance both cellular and humoral immunity in mice, demonstrating how phages can be used as adjuvants to stimulate mucosal immunity and act as promising candidates for oral vaccination.

Anti-leishmaniasis Effect of Staphylococcus Aureus Protein A on the Size of the Lesion and Parasitic Load.

Background: Many studies in the past have evaluated the role of immune system boosters in the treatment of leishmania major infection. Protein A (PA) is one of the structural components in peptidoglycan cell wall of gram-negative bacteria such as staphylococcus aurous which functions as a stimulator in the cellular immune system. The present study aims to evaluate the anti-inflammatory effect of PA on the recovery of leishmania major infection. Materials and Methods: This study was conducted on 24 female Balb/c-infected mice. The experimental group received PA at a dose of 60 mg/kg for four weeks. There was no intervention for the negative control group; the third group received the solvent of PA and sterile H2O; and the positive control group received Amphotericin B at a dose of 1 mg/kg body weight. At the end of the treatment period, a real-time polymerase chain reaction (PCR) assay was performed to determine parasitic burden, and the size of the lesions was measured by caliper with an accuracy of 0.01 mm. Results: Results showed that PA did slightly decrease the wound spread and growth but not to an extent that can be considered statistically significant. Also, differences in cycle threshold (Ct) values between the treated group and the untreated group was not impressive. Conclusions: Although findings showed that PA isn't such a good candidate for leishmania treatment, it may still be suitable for therapies that use multiple drugs in combination to speed up the healing of leishmaniosis, an issue that merits evaluation in future studies.

Sensitive, Real-time and Non-Intrusive Detection of Concentration and Growth of Pathogenic Bacteria using Microfluidic-Microwave Ring Resonator Biosensor.

Infection diagnosis and antibiotic susceptibility testing (AST) are time-consuming and often laborious clinical practices. This paper presents a microwave-microfluidic biosensor for rapid, contactless and non-invasive device for testing the concentration and growth of Escherichia Coli (E. Coli) in medium solutions of different pH to increase the efficacy of clinical microbiology practices. The thin layer interface between the microfluidic channel and the microwave resonator significantly enhanced the detection sensitivity. The microfluidic chip, fabricated using standard soft lithography, was injected with bacterial samples and incorporated with a microwave microstrip ring resonator sensor with an operation frequency of 2.5 GHz and initial quality factor of 83 for detecting the concentration and growth of bacteria. The resonator had a coupling gap area on of 1.5 × 1.5 mm2 as of its sensitive region. The presence of different concentrations of bacteria in different pH solutions were detected via screening the changes in resonant amplitude and frequency responses of the microwave system. The sensor device demonstrated near immediate response to changes in the concentration of bacteria and maximum sensitivity of 3.4 MHz compared to a logarithm value of bacteria concentration. The minimum prepared optical transparency of bacteria was tested at an OD600 value of 0.003. The sensor's resonant frequency and amplitude parameters were utilized to monitor bacteria growth during a 500-minute time frame, which demonstrated a stable response with respect to detecting the bacterial proliferation. A highly linear response was demonstrated for detecting bacteria concentration at various pH values. The growth of bacteria analyzed over the resonator showed an exponential growth curve with respect to time and concurred with the lag-log-stationary-death model of cell growth. This biosensor is one step forward to automate the complex AST workflow of clinical microbiology laboratories for rapid and automated detection of bacteria as well as screening the bacteria proliferation in response to antibiotics.

Differentiation of Human Scalp Adipose-Derived Mesenchymal Stem Cells into Mature Neural Cells on Electrospun Nanofibrous Scaffolds for Nerve Tissue Engineering Applications.

OBJECTIVES: This study aimed to isolate and culture SADS cells, investigate their neurogenic capacity and evaluate their application for nerve tissue engineering. MATERIALS AND METHODS: In this experimental study, SADS cells were isolated from human adipose tissue. After 7-day treatment of SADS cells with insulin, indomethacin and isobutylmethylxanthine, neurogenic differentiation of SADS cells was investigated. During this study, Poly (ε-caprolactone) (PCL) and PCL/gelatin nanofibrous scaffolds were fabricated using electrospinning and subsequently nanofibrous scaffolds were coated with platelet-rich plasma (PRP). SADS cells were also seeded on nanofibrous scaffolds and neurogentic differentiation of these cells on nanofibers was also evaluated. Effect of PRP on proliferation and differentiation of SADS cells on scaffolds was also studied. RESULTS: Our results showed that after 7-day treatment of SADS cells with insulin, indomethacin and isobutylmethylxanthine, SADS cells expressed markers characteristic of neural cells such as nestin and neuron specific nuclear protein (NEUN) (as early neuronal markers) as well as microtubule-associated protein 2 (MAP2) and neuronal microtubule-associated (TAU) (as mature neuronal markers) while mature astrocyte maker (GFAP) was not expressed. MTT assay and SEM results showed that incorporation of gelatin and PRP into the structure of nanofibrous scaffolds has a significant positive influence on the bioactivity of scaffolds. Our results also showed neurogentic differentiation of SADS cells on scaffolds. CONCLUSIONS: Our results demonstrated that SADS cells have potential to differentiate into early and mature progenitor neurons, in vitro. PCL/gelatin/PRP was found to be a promising substrate for proliferation of SADS cells and differentiation of these cells into neural cells which make these scaffolds a candidate for further in vivo experiments and suggest their application for nerve tissue engineering.