Protective immune potential of cysteine peptidases-shared multiple antigen peptide against murine schistosoma mansoni infection / Aya Zuhair Ibrahim Alnaseri ; Supervised Rashika Elridi , Noha Ahmed Mahana

Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Zoology

Enzymatically active and inactive cysteine peptidases (CPs), including papain, induced highly significant (P < 0.0001) protection (50-60%) against challenge Schistosoma mansoni and S. haematobium in immunized mice and hamsters, respectively, by skewing the immune responses toward the type 2 axis. The data together suggested that there is a common peptide shared among these molecules and is responsible for their protective capacity. Therefore, a peptide shared among CPs with the highest homology to helminths cathepsin L was synthesized as a tetrabranched multiple antigen peptide (MAP), designated as MAP-2, and examined in parallel with papain for protective capacity and immune responses against challenge S. mansoni infection in CD-1 outbred mice. Immunization with MAP-2 elicited reduction of 35.7% in challenge worm burden compared to unimmunized mice, albeit lower than that achieved by papain (50%), with no increase in liver and small intestine egg counts. Contrary to papain, MAP-2 immunization induced remarkable increase in small intestine, the parasite egg exit site, granuloma count and areas. Alongside, immune responses were of the type 2 cytokines and antibodies (IgG1 and IgA), and remarkably modest to MAP-2, which should, thus, be incorporated with a strong adjuvant for producing high levels of antibodies able to counteract its parasite egg protective potential

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