The characterisation of an esterase derived fromBabesia bovis and its use as a vaccine

Abstract

An esterase was isolated from a crude extract of Babesia bovis by affinity chromatography, using soy bean trypsin inhibitor as a ligand. In native form this enzyme had a molecular weight greater than 200 000, but on denaturing gels major bands were observed with molecular weights of 20 000, 10 000 and 7 000. Western transfer analysis revealed a major band with a molecular weight of 19 000-20 000. Both bovine and rabbit antisera avidly stained infected red cells, using indirect immunofluorescence. Weak parasite staining was also observed using this test. Two groups of five animals were vaccinated twice 4 weeks apart with esterase derived from 5 X 10(9) parasites as water-in-oil emulsions with Freund's complete adjuvant. Two control groups, each of five animals were also included. One group of vaccinates and a control group were challenged with virulent homologous B. bovis, whilst the other vaccinated and the remaining control group were challenged with virulent heterologous organisms. In the homologous groups two controls but no vaccinates died, whereas in the heterologous groups four animals in each group died. Significant differences in parasitaemia, temperature rise and total haemolytic complement were observed in the homologous vaccinated group compared to their controls but no differences were observed between heterologous groups.

Protective vaccination against virulent Babesia bovis with a low-molecular-weight antigen

“…A direct comparison between the 15B1purified antigen in native form (21) and crude material (7) plasma conglutinin and fibrinogen levels were relatively similar in both groups. However, the severity of infection in control animals was similar to that observed in nonsplenectomized susceptible cattle in previous experiments in which the Samford challenge strain was used (19). Variability of reaction occurs in these experiments due to the small number of outbred animals used.…”

“…Electrophoresis. Affinity-purified antigen, together with lysate fractions of B. bovis-infected and normal erythrocytes, were electrophoresed on 5 to 15% gradient acrylamide containing 0.1% sodium dodecyl sulfate and 0.5 M urea (19). A series of protein standards (Pharmacia, Uppsala, Sweden) ranging from phosphorylase b (94 kilodaltons [kd]) to oxlactalbumin (14 kd) were run on adjacent tracks.…”

Coinfection with Antigenically and Genetically Distinct Virulent Strains of Babesia bovis Is Maintained through All Phases of the Parasite Life Cycle

“…During days 9 through 11 for c4537 and days 9 through 12 for c4574, the L strain represented the majority of the parasite population, while on day 13 for both calves, the T2Bo strain predominated. The total parasite loads at 13 dpi were 1.86 ϫ 10 3 parasites/l whole blood for c4537 and 3.57 ϫ 10 3 parasites/l whole blood for c4574, which are comparable to those in calves with intact spleens inoculated with the T2Bo or L strain alone (8,27). The results clearly demonstrate that cattle with intact spleens can be coinfected by a blood stabilate with two virulent strains of B. bovis.…”

PROTECTIVE ANTIGENS IN FRACTIONS OF ADULT NEMATOSPIROIDES DUBIUS

“…SDS-PAGE under reducing conditions separated Fl polypeptides in the molecular weight range 40,000-110,000. This distribution probably relates to the dislocation of large molecules and to the dissociation of molecules from complexes (Wright et al, 1983a). We have detected mouse immunoglobulins in homogenates of N. dubius mainly associated with Fl Sephadex G-200 filtrates.…”