The Search of a Malaria Vaccine: The Time for Modified Immuno-Potentiating Probes

Abstract

Malaria is a deadly disease that takes the lives of more than 420,000 people a year and is responsible for more than 229 million clinical cases globally. In 2019, 95% of malaria morbidity occurred in African countries. The development of a highly protective vaccine is an urgent task that remains to be solved. Many vaccine candidates have been developed, from the use of the entire attenuated and irradiated pre-erythrocytic parasite forms (or recombinantly expressed antigens thereof) to synthetic candidates formulated in a variety of adjuvants and delivery systems, however these have unfortunately proven a limited efficacy. At present, some vaccine candidates are finishing safety and protective efficacy trials, such as the PfSPZ and the RTS,S/AS01 which are being introduced in Africa. We propose a strategy for introducing non-natural elements into target antigens representing key epitopes of Plasmodium spp. Accordingly, chemical strategies and knowledge of host immunity to Plasmodium spp. have served as the basis. Evidence is obtained after being tested in experimental rodent models for malaria infection and recognized for human sera from malaria-endemic regions. This encourages us to propose such an immune-potentiating strategy to be further considered in the search for new vaccine candidates.

Monkeypox virus: A review

“…The LC16 vaccine is derived from the Lister strain and has a B5R immunogenic membrane protein deletion. It is delivered via the skin using a bifurcated needle and can be administered to individuals of all ages, such as infants and children, as part of a multi-dose regimen [ [73] , [74] , [75] , [76] ]. In order to identify the most effective vaccine, it is crucial to evaluate factors such as reactogenicity, safety, and vaccine-related adverse events, particularly for high-risk and vulnerable populations.…”

Monkeypox: potential vaccine development strategies

“…In addition, second-generation vaccines have not been proven to be a reliable pathway toward subunit vaccines due to their low stability and specificity. On the contrary, low-cost, stable, specific, nontoxic, and safe molecules produced by controlled synthesis strategies have become a reality for obtaining vaccine formulations for multiple lethal diseases, such as malaria and COVID-19 [ 13 , 14 ].…”

“…An important finding in experiments conducted by us and others is that site-directed designed synthetic epitopes when administered in animal models as vaccine formulations stimulate not only the production of expected antihomologous peptide antibodies but also that of antibodies that cross-react with viral proteins, including antibodies displaying neutralizing properties [ 13 , 15 ]. We have shown that intravenous administration of site-directed antibodies stimulated by synthetic peptides encompassing specific epitopes cleared different circulating malaria pathogen strains in rodents [ 13 ], a strategy that could be applied to diseases caused by viruses such as MPXV. Synthetic platforms do not require cold chains since this sort of vaccine product has proven to be highly stable even at room temperature for long time periods.…”

Development of a Trivalent Construct Omp18/AhpC/FlgH Multi Epitope Peptide Vaccine Against Campylobacter jejuni

“…Such vaccine features the advantages of simultaneous presentation of multiple antigenic epitopes, greater presentation of antigen, and non-covalent binding between antigenic peptide branches so as to form epitopes and to enhance immune effects. In the meantime, individual amino acid mutations could not affect presentation of antigen and the subsequent immune response ( Lozano et al, 2021 ). Over the recent years, it is found that C. jejuni Omp18, AhpC outer membrane protein, and FlgH flagellin subunit feature numerous advantages, including but not limited to strong antigenicity, expression in varying strains, and sequence conservation ( Watson et al, 2014 ; Guérin et al, 2020 ; Quintel et al, 2020 ).…”