Immunological characterization and expression in Escherichia coli and Baculovirus systems of a Trypanosoma vivax antigen detected in the blood of infected animals

Abstract

A monoclonal antibody (MAb)Tv27 employed in an antigen-detection enzyme immunosorbent assay (Ag-ELISA) for diagnosis of Trypanosoma vivax infection was shown to react with a T. vivax-specific protein of an approximate molecular weight of 10 kDa. This protein is diffusely distributed throughout the cytosol and nucleus of metacyclic forms, bloodstream forms, and procyclic-like elongated trypomastigotes, but is not detectable in epimastigotes of T. vivax. The T. vivax-specific antigen prepared from parasite lysates appeared to be of lower molecular mass than the form expressed in either Escherichia coli or in baculovirus-infected silkworm insect cells. In the recombinant baculovirus-infected cells, the protein was expressed mostly as an 18-kDa peptide with less abundant forms of 13 and 12 kDa, while the protein expressed in E. coli was approximately 14 kDa. Both the low- and higher-molecular-weight proteins are recognized by the MAb Tv27 in Western blots and in Ag-ELISA. Although the crude preparations of the protein produced by the insect cells are labile when kept for more than 2 hr at 24°C, they retained reactivity at temperatures below 4°C for several weeks. The proteins expressed in both the insect cells and E. coli captured anti-T. vivax antibodies in sera prepared from trypanosome-infected animals. Since the recombinant protein expressed in the baculovirus-infected cells is available in large homogenous quantities, it would serve as a positive control in Ag-ELISA and is also usable for antibody detection assays.

Citation

Experimental Parasitology;81: 536-545

Authors

  • Masake, R.A.
  • Ole-MoiYoi, O.K.
  • Urakawa, T.
  • Hirumi, H.
  • Majiwa, Phelix A.O.
  • Wells, C.W.
  • Minja, S.H.
  • Makau, J.M.
  • Nantulya, V.M.