Identification of a candidate vaccine peptide on the 37 kDa Schistosoma mansoni GAPDH
Introduction
Five to fifteen percent of subjects infected by Schistosoma mansoni develop a severe hepatosplenic disease that may be fatal if left untreated [1]. As many water-borne diseases, schistosomiasis is spreading in developing countries where irrigation programs are implemented to sustain agriculture development. Although infections can be cured by schistosomicides, chemotherapy is not appropriate for the long-term control of this endemy and a major WHO objective is the development of a vaccine against schistosomiasis [2]. For practical, economical and safety reasons, the ideal vaccine must be a sub-unit one and many research efforts are focused on the identification of schistosome molecules that could be included in the vaccine. This search is carried out along two complementary lines in animal models and in epidemiological studies in human populations. Antigens have been looked for in murine experimental models of schistosomiasis using protective monoclonal or polyclonal antibodies; some of these antigens were shown to induce protection in mice and/or rats against challenges by schistosome cercariae [3], [4], [5], [6], [7], [8], [9], [10], [11]. Protective levels were comprised between 20 and 50%. The reasons why full protection could not be reached in animals are unknown, this may have to do with some particularities of the mouse and rat experimental models.
In the past decade, various observations indicated that certain humans living in endemic areas of S. mansoni exhibit high level of anti-schistosome immunity that is close to full protection for certain subjects [12], [13]. These findings led our group and others to attempt to identify vaccinating antigens among the major antigens recognized by antibodies and T cells from resistant individuals. It was also hoped that this strategy would lead to the selection of molecules capable of inducing a protective immune response that would be efficiently recalled by natural infections. Along these lines, our laboratory has identified and characterized the schistosome Sm37-GAPDH [13], [14] and Sm10-DLC [15], [16] molecules as major targets respectively of antibodies and T cells from resistant subjects. The aims of the present work was to evaluate whether peptides corresponding to antigenic determinants on schistosome GAPDH could be valid candidates to a subunit vaccine.
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Reagents
BSA, Tween 20, NBT-BCIP (nitro blue tetrazolium-bromo chloro indolyl phosphate) and pNPP (para-nitrophenyl phosphate) were from Sigma Chemicals Co. (St Louis, MO, USA). Alkaline phosphatase-coupled rabbit anti-human IgG, IgG1 and IgG2; alkaline phosphatase-coupled goat anti-mouse IgG; mouse anti-human IgG3, IgG4 and Ig light chain; mouse IgG and human IgG, IgG1, IgG2, IgG3, IgG4 myeloma immunoglobulins were from Immunotech (Marseille, France).
Serum samples
Sera were obtained from 156 individuals aged from 4
Identification of Sm37 B cell epitopic regions
An expression library was constructed from the cDNA coding for Sm37. Fragments were generated by DNAse I digestion and were hence expected to end at all possible random positions. The library was screened with an anti-Sm37 rabbit immune serum. All detected phages were kept for further characterization. Ten of them (A, C, D, E, F, G, H, K, X and Y) were randomly chosen and used to affinity purify specific antibodies from the immune serum. These antibody preparations allowed the definition of
Discussion
Analysis by Western blot and ELISA of the reactivity of schistosome larval surface antigens with antibodies of adolescents from an endemic area showed that a 37 kDa antigen reacted preferentially with sera from subjects who resisted reinfection after chemotherapy [13]. The cDNA of Sm37 was cloned and shown to encode the schistosome glyceraldehyde-3-phosphate dehydrogenase [14]. Since the immunological properties of schistosome GAPDH indicated that it could be the target of protective immunity,
Acknowledgements
This work received financial assistance from INSERM, CNRS, CEE (TS3-CT94-0296) and from the UNDP/World Bank/WHO (920-349) Special Program for Research and Training in Tropical Diseases. L. Argiro was supported by a fellowship from the Conseil Régional PACA.
References (38)
Controlling schistosomiasis by vaccination: a realistic option?
Parasitology Today
(1995)- et al.
Identification by monoclonal antibody of a major (28 kDa) surface membrane antigen of Schistosoma mansoni.
Molec. Biochem. Parasitol.
(1985) - et al.
A 14-kDa Schistosoma mansoni polypeptide is homologous to a gene family of fatty acid binding proteins
J. Biol. Chem.
(1991) - et al.
Immunity after treatment of human schistosomiasis mansoni. II Identification of resistant individuals, and analysis of their immune responses
Trans. Roy. Soc. Trop. Med Hyg.
(1985) - et al.
Schistosoma mansoni: a defined system for stepwise transformation of the cercariae to schistosomule in vitro.
Exp. Parasitol.
(1974) - et al.
Schistosoma mansoni: rapid isolation and purificaton of schistosomula of different developmental stages by centrifugation on discontinuous density gradients of Percoll
Exp. Parasitol.
(1982) - et al.
Selective inactivation of the exonuclease activity of bacteriophage T7 DNA polymerase by in vivo mutagenesis
J. Biol. Chem.
(1989) - et al.
Studies of asymmetry in the three-dimensional structure of lobster d-glyceraldehyde-3-phosphate dehydrogenase
J. Biol. Chem.
(1975) - et al.
Comparison of the structures of wild-type and a N313 T mutant of Escherichia coli glyceraldehyde 3-phosphate dehydrogenases: implication for NAD binding and cooperativity
J. Molec. Biol.
(1996) - et al.
Induction of a protective immunity against Shistosoma mansoni with ovalbumin-coupled Sm37-5 coadsorbed with granulocyte-macrophage colony stimulating factor (GM-CSF) or IL-12 on alum
Vaccine
(1999)
Detrimental effect of nitric oxide on Trypanosoma cruzi and Leishmania major life cells
Acta Tropica
Immunochemical characterization and purification of Sm-97, a Schistosoma mansoni antigen monospecifically recognized by antibodies from mice protectively immunized with a nonliving vaccine
J. Immun.
Molecular cloning of a protective antigen of schistosomes
Nature
A purified 28,000 dalton protein from Schistosoma mansoni adult worms protects rats and mice against experimental schistosomiasis
J. Immunol.
Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae
J. Immun.
An immunogenic Mr 23,000 integral membrane protein of Schistosoma mansoni worms that closely resembles a human tumor-associated antigen
J. Immun.
Induction of protective immunity in mice using a 62-kDa recombinant fragment of a Schistosoma mansoni surface antigen
J. Immun.
T and B cell epitope mapping of Sm23, an integral membrane protein of Schistosoma mansoni.
J. Immun.
Cited by (0)
- 1
The first two authors have contributed equally to this work.
- 2
Present address: Institut für Medizinische Virologie, Heidelberg, Germany.