GP38, P28-I and P28-II: candidates for a vaccine against Schistosomiasis

Abstract

Three antigens protective against Schistosoma mansoni have been extensively characterized. The schistosomulum surface antigen GP38 possesses an immunodominant carbohydrate epitope of which the structure has been defined. Protection can be achieved via the transfer of monoclonal antibodies recognizing the epitope or by immunization with anti-idiotype monoclonal antibodies. The glycan epitope is shared with the intermediate host, Biomphalaria glabrata as well as being present on other molluscs, including the Keyhole Limpet. A group of molecules at 28 kDa were initially characterized in adult worms and shown to protect rats and mice against a challenge infection. One of these molecules, P28-I, was cloned and expressed in E. coli, yeast and vaccinia virus. The recombinant antigen significantly protected rats, hamsters and baboons against a challenge infection. P28-I is a glutathione-S-transferase and the recombinant antigen produced in yeast exhibits the enzyme activity and has been purified to homogeneity by affinity chromatography. A second P28 antigen, P28-II, has also been cloned, fully sequenced and expressed. This recombinant antigen also protects against S. mansoni infection.

Adaptive Developmental Delay in Chagas Disease Vectors: An Evolutionary Ecology Approach

“…This stage is one of the most “resistant” stages in triatomines; e.g., the 5th instar nymph is one of the stages most resistant to starvation in many triatomine species: this characteristic has been confirmed in T. brasiliensis [45], [46], in T. lecticularia [47], in T. tibiamaculata , P. megistus , and in R. neglectus [48], in Dipetalogaster maximus [49], in Cavernicola lenti [50], in T. vitticeps [51], and in T. melanosoma [52]. Moreover, the 5th instar nymphs are the most resistant to insecticides in T. infestans and R. prolixus [53]–[55].…”

Vaccine efficacy of recombinant cathepsin D aspartic protease from Schistosoma japonicum

“…Although IgE antibodies (associated with Th2 responses) correlate with protection in human and rat schistosomiasis, they do not appear to play an essential role in murine schistosomiasis (30). The IgG2 response to r Sj ASP2 may be against carbohydrate molecules present as a result of N ‐terminal glycosylation during its expression in insect cells, and while carbohydrate epitopes have been shown to be important in inducing protective responses (31,32), the carbohydrates added to r Sj ASP2 during its expression may not be identical to those in the native schistosome aspartic protease. Indeed, the protective efficacy of the native schistosome cathepsin D may differ substantially from what is reported here, due to structural differences or absence of post‐translational modifications in recombinant proteins.…”

Evaluation of recombinant protein r140, a polypeptide segment of tegumental glycoprotein Sm25, as a defined antigen vaccine against Schistosoma mansoni

“…It is possible that the requisite protective response may be directed against the carbohydrate moieties of Sm25 and we have only generated an anti-peptide response by using a nonglycosylated antigen. Importance of carbohydrate epitopes in inducing protective antibodies has been well documented with Sm38 and S. mansoni egg antigens (Grzych et al 1987, Pierce et al 1987.…”