Liposome-Mediated Delivery of MERS Antigen Induces Potent Humoral and Cell-Mediated Immune Response in Mice

The advancements in the field of nanotechnology have provided a great platform for the development of effective antiviral vaccines. Liposome-mediated delivery of antigens has been shown to induce the antigen-specific stimulation of the humoral and cell-mediated immune responses. Here, we prepared dried, reconstituted vesicles (DRVs) from DPPC liposomes and used them as the vaccine carrier system for the Middle East respiratory syndrome coronavirus papain-like protease (DRVs-MERS-CoV PLpro). MERS-CoV PLpro emulsified in the Incomplete Freund’s Adjuvant (IFA-MERS-CoV PLpro) was used as a control. Immunization of mice with DRVs-MERS-CoV PLpro did not induce any notable toxicity, as revealed by the levels of the serum alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the blood of immunized mice. Immunization with DRVs-MERS-CoV PLpro induced greater antigen-specific antibody titer and switching of IgG1 isotyping to IgG2a as compared to immunization with IFA-MERS-CoV PLpro. Moreover, splenocytes from mice immunized with DRVs-MERS-CoV PLpro exhibited greater proliferation in response to antigen stimulation. Moreover, splenocytes from DRVs-MERS-CoV PLpro-immunized mice secreted significantly higher IFN-γ as compared to splenocytes from IFA-MERS-CoV PLpro mice. In summary, DRVs-MERS-CoV PLpro may prove to be an effective prophylactic formulation to prevent MERS-CoV infection.

Feasibility Study of Using Uncrewed Aerial Vehicles to Deliver COVID-19 Vaccines in Geographically Inaccessible Areas of Nepal

Background: The infectious diseases vaccine program started in Nepal. Transportation facilities using uncrewed aerial vehicles (UAVs) will support the COVID 19 vaccine; therefore, remote areas where accessibility is unavailable and takes enormous time to reach the primary health center. However, it can distribute vaccines at standard times with required temperature-sensitive. Moreover, eliminating human contact reduces logistics cost, time, and chances of virus carriers to the frontline workers while delivering vaccines. Methods: This feasibility study provides one of the possible ways of transporting vaccines using UAVs to the remote areas of Nepal; one approach will be using a customize prototype of drones and deploying it. The following will to studying the research articles on this field for proper guidance to conduct a study. The drone with a vaccine carrier takes the vaccine from Simikot Airport to the Local 18 Mission hospital about a 400-meter journey time of about 11-15 minutes. Results: The results show that drones can supply medical kits to health centers to reduce delivery time. It has been practicing that literature review on this related field states UAVs' possible implication in transporting vaccines. It reduces the time to deliver by 11-15 minutes with a vaccine carrier box (10-12 kg) that maintains a low temperature for 3-7 days. Furthermore, it minimizes the potential risk of not providing vaccines due to the unavailability of the road in remote areas. Conclusion: This alternative can support the delivery of vaccines for vulnerable groups deprived of health care. One of the significant ways to deliver the vaccine can be using a drone for remote areas with limited health facilities. In addition, it can support government plans to vaccine people incorporation with emerging technologies.

Bacillus Subtilis Spores as Delivery System for Nasal Plasmodium Falciparum Circumsporozoite Surface Protein Immunization in a Murine Model

Malaria remains a widespread public health problem in tropical and subtropical regions around the world, and there is still no vaccine available for full protection. In recent years, it has been observed that spores of Bacillus subtillis can act as a vaccine carrier and adjuvant, promoting an elevated humoral response after co-administration with antigens either coupled or integrated to their surface. In our study, B. subtillis spores from the KO7 strain were used to couple the recombinant CSP protein of P. falciparum (rPfCSP), and the nasal humoral-induced immune response in Balb/C mice was evaluated. Our results demonstrate that the spores coupled to rPfCSP increase the immunogenicity of the antigen, which induces high levels of serum IgG, and with balanced Th1/Th2 immune response, being detected antibodies in serum samples for 250 days. Therefore, the use of B. subtilis spores appears to be promising for use as an adjuvant in a vaccine formulation.

Determination of transgene stability in Nannochloropsis sp. transformed with immunogenic peptide for oral vaccination against vibriosis

Vibriosis is one of the common diseases caused by gram-negative bacteria from the genus Vibrio. To treat vibriosis, vaccination has been proven to be the most effective treatment as it can avoid the risk of drugs or antibiotics resistance. Microalgae are commonly used as feed for aquatic organisms and Nannochloropsis sp. is one of the highly utilized species for fish feed. This study focused on the use of microalga, Nannochloropsis sp. as a vaccine carrier. Transgenic Nannochloropsis sp. harbouring an outer membrane protein kinase (OmpK) gene fragment of the Vibrio species namely V1, V2, CV1, CV2, CPV1 and CPV2 were utilized in this study. The stability of OmpK gene in transgenic Nannochloropsis sp. over a number of generations was evaluated. DNA and RNA from the Nannochloropsis sp. transgenic lines were extracted and subjected to PCR amplification of OmpK gene fragment. The OmpK gene fragment was successfully amplified and expressed up to the fifth generation (F5). For V1, V2, CV1 and CV2, the gene was present and expressed in fourth generation (F4) and F5 respectively but CPV1 and CPV2 the OmpK genes were present up to F4. From the results obtained, Nannochloropsis sp. is shown to be suitable as a vaccine carrier and can be utilized as a vaccine carrier to ameliorate vibriosis.

Selective tumor antigen vaccine delivery to human CD169+antigen-presenting cells using ganglioside-liposomes

Priming of CD8+T cells by dendritic cells (DCs) is crucial for the generation of effective antitumor immune responses. Here, we describe a liposomal vaccine carrier that delivers tumor antigens to human CD169/Siglec-1+antigen-presenting cells using gangliosides as targeting ligands. Ganglioside-liposomes specifically bound to CD169 and were internalized by in vitro-generated monocyte-derived DCs (moDCs) and macrophages and by ex vivo-isolated splenic macrophages in a CD169-dependent manner. In blood, high-dimensional reduction analysis revealed that ganglioside-liposomes specifically targeted CD14+CD169+monocytes and Axl+CD169+DCs. Liposomal codelivery of tumor antigen and Toll-like receptor ligand to CD169+moDCs and Axl+CD169+DCs led to cytokine production and robust cross-presentation and activation of tumor antigen-specific CD8+T cells. Finally, Axl+CD169+DCs were present in cancer patients and efficiently captured ganglioside-liposomes. Our findings demonstrate a nanovaccine platform targeting CD169+DCs to drive antitumor T cell responses.