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.

Hepatitis C is a public health problem worldwide, affecting chronically about 71 million people, or 1% of the world population. The early detection of infection in clinical practice routine and blood donors is still important, being necessary for the development of new specific, sensitive, reliable tests that can improve the screening of HCV infection. Flow cytometry beads assay opens the possibility to detect multiple antigens, decrease cross-reactivity, increase in the sensitivity, with low sample volumes. Here, we describe proof-of-concept of a method for anti-Core and anti-NS5a detection using magnetic beads and flow cytometry. The immunoassay presented 93.33% sensitivity and 100% specificity for rCore magnetic beads (MgBs), and 93.33% sensitivity and 96.67% specificity for rctNS5a MgBs. The accuracy values for the tests using rCore and rctNS5a MgBs were 96.67% and 95%, respectively. The results of the ROC curve were 0.97 and 0.99 for rCore and rctNS5a MgBs, respectively. Therefore, we concluded that the method presented here for the detection of anti-HCV antibodies using magnetic beads analyzed by flow cytometry showed promising results, achieving satisfactory sensitivity and specificity values, with future potential to be an alternative method for screening anti-HCV antibodies in blood banks and blood centers.

Despite the many efforts of researchers around the world, there is currently no effective vaccine for malaria. Numerous studies have been developed to find vaccine antigens that are immunogenic and safe. Among antigen candidates, Plasmodium falciparum merozoite surface protein 3 (MSP3) has stood out in a number of these studies for its ability to induce a consistent and protective immune response, also being safe for use in humans. This review presents the main studies that explored MSP3 as a vaccine candidate over the last few decades. MSP3 formulations were tested in animals and humans and the most advanced candidate formulations are MSP3-LSP, a combination of MSP3 and LSP1, and GMZ2 (a vaccine based on the recombinant protein fusion GLURP and MSP3) which is currently being tested in phase II clinical studies. This brief review highlights the history and the main formulations of MSP3-based vaccines approaches against P. falciparum .

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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.