Production and characterization of a monoclonal antibody specific to 16 kDa antigen of Paramphistomum gracile

The anthelmintic potentials of medicinal plant extracts and an isolated compound (rutin, C27H30O16) from Terminalia catappa L. against Gastrothylax crumenifer

Paramphistomosis is a pathogenic disease that occurs frequently in tropical and subtropical countries including Thailand. This disease is affected in the parasites causing severe gastrointestinal disorders and death in infected animals. In the present study, we examined the anthelmintic efficacy of albendazole (ABZ) and crude plant extracts from barks of Bombax ceiba L., Diospyros rhodocalyx Kurz. and Vitex glabrata R.Br., and leaves of Terminalia catappa L. and Cassia alata L. against Gastrothylax crumenifer. The hightest anthelmintic activity on the parasites after 24 h incubation was observed in the n-butanol extract of T. catappa leaf. In this study, fractionation bioassay of n-butanol extract of T. catappa leaf was conducted to both separation and discrimination of rutin served as a new efficient compound (LC₅₀ = 28.96; LC₉₀ = 88.75 μg/mL) against G. crumenifer. This compound was confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, infrared (IR) and ultraviolet (UV) spectra as well as mass spectra data. The rutin-treated parasites with all dosages showed swift decrease of the motility and the relative motility (RM) and survival index (SI) were decreased obviously from 3 h until flukes were killed after 12 h of incubation. When observed with light microscopy, the parasites showed the earliest change in a limited region of the tegument. When observed by scanning electron microscopy, the parasites' tegument exhibited similar sequences of surface changes after treatments with rutin and ABZ, but less severity in ABZ treatment. The sequences of changes comprised swelling of folds and ridges, formation of blebbing, rupturing of blebs, erosions, lesions and the tegument demolition. Hence, rutin could be considered as the potential anthelmintic agent for treatment of paramphistomosis.

Recombinant expression and characterization of major surface protein 4 from Anaplasma marginale

Anaplasma marginale is the rickettsia which causes the bovine anaplasmosis. The distribution of A. marginale is both tropical and subtropical regions of the world. The major surface protein 4 (MSP4) of this parasite was identified as an immunodominant protein. In this study, the full length of DNA encoding A. marginale MSP4 (AmMSP4) was cloned from the parasites. The open reading frame of msp4 coding sequence of Thailand strain is 849 bp. Phylogenetic analysis revealed that the msp4 coding sequence of A. marginale was highly conserved when compared with Anaplasma phagocytophilum. The recombinant plasmid was further transformed into the BL21-CodonPlus (DE3)-RIPL competent cells for over-expression of the recombinant major surface protein 4 of A. marginale (rAmMSP4). Sera from rabbit immunized with rAmMSP4 and from cattle infected with A. marginale were used to study the antigenicity of rAmMSP4 (35 kDa) and AmMSP4 (31 kDa). Both rAmMSP4 and AmMSP4 were recognized by these sera showing that recombinant and native AmMSP4 have conserved epitopes. Localization of Anaplasma parasites by immunofluorescence showed these parasites are distributed on both the membrane and the outside of infected erythrocytes. Regarding antigenicity, recombinant MSP4 could be used for immunodiagnostic purposes and as a possible vaccine candidate against anaplasmosis.

Diagnostic potential of low molecular weight excretory secretory proteins of Paramphistomum epiclitum for caprine amphistomosis

In the present study, the 75% alcoholic fractionation of excretory-secretory (ES) antigen isolated from 200 to 300 live P. epiclitum was assessed for its diagnostic potential for the detection of caprine amphistomosis by using antibody detection enzyme immunoassay. Prior to enzyme immunoassay, 75% alcoholic fractionation of excretory-secretory (ES) antigen was subjected to SDS- PAGE and western blot analysis for the presence of immunoreactive polypeptides. SDS-PAGE analysis of ES antigen resolved a total 7 polypeptides bands of size 56, 27, 25, 22.5, 12, 11 and 10 kDa. Western blot analysis revealed only two immunoreactive polypeptides (11 kDa and 12 kDa) when polypeptides resolved in SDS-PAGE were probed with known positive pooled serum. None of the polypeptides showed reactions with pooled known negative serum. The working dilutions of antigen, sera and conjugates were determined by checkerboard titration for employing ELISA and cut-off O.D. was calculated 0.616 by using the mean absorbance value of 11 negative kid sera. The sensitivity and specificity of ELISA was found to be 100% and 86.76%, respectively. As per kappa value estimation, the strength of agreement was found to be good. Antibodies to 75% alcoholic fractionation of ES antigen was detected in 20% goats (n = 160) of either sex, although faecal examination detected 10.6% goats to be infected with amphistomosis. The study confirmed that 75% alcoholic fractionation of ES antigen of P. epiclitum based ELISA had good value for serodiagnosis of caprine amphistomosis.

The in vitro anthelmintic activity of the ethanol leaf extracts of Terminalia catappa L. on Fasciola gigantica

At present, there are no medicinal plant extracts currently available for treatment and control of fasciolosis. The present work could provide, for the first study, conclusions on the in vitro fasciolicidal properties of the ethanol extract of Terminalia catappa L. (TcCE) leaves against adult Fasciola gigantica after incubation with RPMI-1640 medium containing the TcCE at various concentrations and times when compared with triclabendazole (TCZ). The relative motility and survival index values of the TcCE-treated flukes decreased at a more rapid rate than the TCZ-treated flukes. The death of the parasites was observed after exposed to TcCE at 3 h incubation with 400, 800 and 1000 µg mL−1, and at 6 h incubation in 100 and 200 µg mL−1. Vacuolization, blebbings and partial disruption on the parasites’ tegument were observed by light microscopy. When examined by scanning electron microscopy, TcCE caused similar tegumental alterations in the parasites as those observed in TCZ treatment but with larger damage at comparative incubation periods, consisting of swelling, blebbing, disrupted blebs, loss of spines, leading to the erosion, lesion and eventual disruption of the total tegument. Therefore, the TcCE may exert its fasciolicidal effect against F. gigantica by initially causing the tegumental alteration.

Paramphistomosis of Ruminants: An Emerging Parasitic Disease in Europe

Whilst historically regarded as being of minor importance in European livestock, recent evidence suggests that the prevalence of paramphistomosis is greater than that of fasciolosis in parts of the UK. In order to address this emerging threat to ruminant farming systems, and associated risks for food security posed by rumen fluke infection, it is imperative that we develop a better understanding of the basic biology of this parasite and how it interacts with its ruminant host. In this Opinion article we review recent progress in tracking the spread of rumen fluke infection in Europe, and propose some research questions that should be addressed if we are to develop tools to diagnose and treat paramphistomosis more effectively in the future.

Immunodiagnosis of paramphistomosis using monoclonal antibody-based sandwich ELISA for detection ofParamphistomum gracilecirculating 16 kDa antigen

In this study, we have produced a monoclonal antibody (MoAb) against 16 kDa antigen ofParamphistomum gracile(16 kDaAgPg), and developed an accurate sandwich enzyme-linked immunosorbent assay (sandwich ELISA) for the detection of circulating 16 kDaAg in the serum and fecal samples from cattle naturally infected withP. gracile. MoAb 1D10 was immobilized on a microtitre plate, and the antigen in the samples was captured and detected with biotinylated rabbit anti-16 kDaAgPg antibody. The lower detection limit of sandwich ELISA was 3·5 pg mL−1, and no cross-reaction with other parasite antigens was evaluated. The reliability of the assay was examined using the serum and fecal samples from cattle naturally infected withP. gracile, Fasciola gigantica, Moniezia benedeni, Trichurissp.,Strongyloidessp., strongylids and non-infected animals. The sandwich ELISA showed the sensitivity, specificity and accuracy at 98·33, 100 and 99·55% (serum samples), and 96·67, 100 and 99·09% (fecal samples). Therefore, this detection method is a rapid and excellent potential assay for the accurate diagnosis of paramphistomosis.