Preliminary studies for development of an immunochromatographic test (ICT) for detection of antibody against salivarian trypanosomes by using recombinant ribosomal P0 protein

Abstract

The aim of the present study was to develop an immunochromatographic test (ICT) for the diagnosis of African trypanosomosis by using recombinant ribosomal P0 protein. The P0 C-terminal domain is highly antigenic and considered to be a major target of the antibody response in infected animals. Entire gene encoding the P0 protein was cloned, and expressed in Escherichia coli as a histidine-tagged recombinant protein (rP0). The rP0 was further purified by using nickel affinity chromatography under denaturing conditions. The rP0 was employed as a capture antigen in order to detect anti-P0 antibody in infected animal sera. Antigen-antibody reaction was detected by either colloidal-gold conjugated protein A or G. The results showed that colloidal gold-conjugated protein A and G were suitable for buffalo and cattle serum samples respectively. The rP0-ICT can detect specific antibody in 12,800-fold dilution serum. All sera from cattle or mouse infected with other protozoan parasites, such as Toxoplasma and Babesia, showed negative results. Field samples (150 serum samples from Uganda) were examined by rP0-ICT and rP0-ELISA showed that the positive rate is 48% (72/150) and 50% (75/150), respectively. The high agreement indicated that the rP0-ICT is reliable. This suggests that the rP0-based ICT can be used as a rapid on-site diagnostic method of salivarian trypanosomosis.