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Staphylococcus aureus has been a serious healthcare concern due to the wide range of diseases caused and the development of antibiotic resistance to almost all antibiotics developed so far. Methicillin resistant Staphylococcus aureus has been particularly damaging due to its enhanced virulence and emergence of community acquired MRSA alongside the hospital acquired MRSA. A preventive immunotherapeutic alternative in the form of vaccines is being pursued by pharmaceutical companies and academic researchers across the globe. Multiple clinical trials to develop a vaccine have not been successful. Recent research data suggest that antigens with the potential to activate a CD4+ T cell mediated immune response rather than a B-cell mediated response would be the key to the development of a vaccine. Here we describe the purification, immunogenicity and insilico functional characterization of a putative metallopeptidase identified to be a CD4+ T cell antigen from S.aureus. The gene coding for the putative peptidase designated as MP1 was isolated using PCR, recombined with pET28a, and transformed into E.Coli BEL21 (DE3). The protein was purified and intraperitoneally administered to BALB/c mice. Protein specific antibodies in mice serum was measured using indirect ELISA. The protein sequence was analyzed for the presence of transmembrane helices, domains and signatures using bioinformatics tools. The protein structure was modeled using Swiss modeler workspace. Our results show that the protein induced significantly higher (p<0.05) antibody responses in immunized mice compared to control mice. The titers of IgG, IgG1 and IgG2a on day 35 after initial immunization were 51200, 25600 and 12800 respectively. Insilico studies revealed that the protein belongs to MEROPS peptidase family M4 and contains the PepSY domain.


Staphylococcus aureus Vaccine Peptidase CD4 T cell antigen Indirect ELISA Modeling

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Dileep Francis, & Surekha Kuyyalil. (2021). Purification, immunogenicity and insilico functional characterisation of a putative metallopeptidase from Staphylococcus aureus. International Journal of Research in Pharmacology & Pharmacotherapeutics, 5(3), 226-234. Retrieved from


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