M.A. Commins

An enzyme linked immunosorbent assay to diagnose Babesia bovis infection in cattle.

The optimum gel filtration fraction from lysate of Babesia bovis infected erythrocytes was determined for use as an antigen in an ELISA to diagnose B. bovis infection in cattle. Of four enzyme labels tested, horseradish peroxidase was the most suitable. The assay is both sensitive and specific in detecting antibody for 2–4 years after a single infection. False positive reactions were obtained only with some sera from some Anaplasma marginale infected cattle.

Artificial feeding of the Australian paralysis tick, Ixodes holocyclus and collection of paralysing toxin

Abstract Unfed or partially-fed female Australian paralysis ticks Ixodes holocyclus have been successfully attached to a silicone rubber membrane and fed on the tissue culture medium TC199 plus additives. Weight gains were well below those expected for ticks feeding on a host but toxin was secreted into the medium and was recovered by ultrafiltration and gel chromatography. The artificially-feeding ticks repeatedly sucked and salivated with a behavioural pattern similar to that of naturally-feeding ticks. The methods of inducing feeding, the monitoring of feeding patterns and the separation of toxin are described. In some experiments the yield of soluble toxin by this method compared favourably with that obtained by extraction of salivary glands but overall the yield was lower.

Proteinases in the lysate of bovine erythrocytes infected with Babesia bovis: initial vaccination studies.

Abstract The lysate of erythrocytes infected with Babesia bovis was tested for proteinases using an electrophoretic method in which substrate was included in the acrylamide matrix. Two babesial proteinases, which seemingly exist in both free and complexed forms, were detected. One of the proteinases was prepared by chromatography and preparative electrophoresis and used to vaccinate four splenectomized calves. The latter, along with a group of control splenectromized calves, were challenged with a strain of B. Bovis from which the proteinase was obtained. All the control calves died whereas only one of the vaccinates died. The protection was evident as a suppression of parasitaemia.

Babesia bovis: Dextran sulphate as an adjuvant for and precipitant of protective immunogens

Dextran sulphate, a chemical with some specificity for lipoproteins, was used to precipitate a fraction from a soluble extract of Babesia bovis-infected erythrocytes. The precipitate, in combination with dextran sulphate as an adjuvant, was used to vaccinate naive calves. The vaccinates and a group of control calves were challenged with virulent homologous B. bovis. The vaccinates showed delayed and decreased parasitaemias comparative to the controls. The antibody response to vaccination was primarily against the infected erythrocyte being of both IgG1 and IgG2 classes. We believe this is the first report of B. bovis antibody being detected in the IgG2 class. Lipase inhibition and chemical analysis suggested babesial lipid or lipoprotein was sufficiently immunogenic to produce serologically detectable antibody and presumably to elicit immunity.

Babesia bovis: vaccination studies with three groups of high molecular weight antigens from lysate of infected erythrocytes.

A void volume fraction and fractions of mean sizes 800 kdalton and 300 kdalton were isolated by gel filtration from lysate of bovine erythrocytes infected with Babesia bovis. All fractions had good serological activity, as assayed by ELISA and IFA. Groups of four splenectomized calves were vaccinated with each fraction and then challenged, together with groups of four control calves, with a homologous strain of B. bovis. The group vaccinated with the 300 kdalton fraction showed some protection, as indicated by delayed and significantly lower parasitaemias and by a 75% survival in the group. In contrast, all animals in the relevant control group died from infection. No evident protection was obtained with the other two fractions.

Babesia bovis : immunity induced by vaccination with a lipid enriched fraction

A chloroform extract from Babesia bovis-infected erythrocytes was used to vaccinate a group of five naive cattle. Following vaccination, the vaccinates, along with a group of control cattle, were challenged with a virulent heterologous strain of B. bovis. The vaccinates, comparative to the controls, showed delayed as well as decreased parasitaemias. The serological and initial biochemical studies suggested that the immune response was elicited by lipid of babesial origin.

A study of autoantibodies to phosphatidyl-serine in Babesia bovis and Babesia bigemina infections in cattle

Sera from cattle infected with Babesia bovis were found to contain antibodies to phosphatidyl-serine (PS), a negatively charged phospholipid normally found on the internal membrane of erythrocytes. In contrast, no autoantibodies were detected following Babesia bigemina infection indicating that the autoimmunity is not genus specific. During infection with Babesia bovis, PS translocates to the external membrane and it is suggested that this may result in PS behaving as an autoantigen owing to a transitional change. These autoantibodies may also play some role in the pathology of infection, especially the disturbed coagulation system associated with acute Babesia bovis infection.

Successful homologous vaccination against Babesia bovis using a heparin-binding fraction of infected erythrocytes

Abstract Goodger B. V. , Commins M.A. , Wright I. G. , Waltisbuhl D. J. and Mirre G. B. 1987. Successful homologous vaccination against Babesia bovis using a heparin-binding fraction of infected erythrocytes. International Journal for Parasitology 17 : 935–940. A heparin binding fraction was obtained from an ultracentrifugal supernatant of Babesia bovis infected erythrocytes. The fraction was used to vaccinate four splenectomised calves and produced high titred antibody directed mainly at the infected erythrocyte. The vaccinated calves, along with a control group of four naive calves, were challenged with homologous infected erythrocytes. The vaccinated calves survived the challenge whereas the control calves did not.

Babesia bovis—effects of phospholipid translocation and adenosine tri-phosphate consumption

The adenosine tri-phosphate concentration of Babesia bovis-infected erythrocytes was significantly (P less than 0.001) less than that of pre-infection erythrocytes. In addition, phosphatidyl serine was detected on the plasmatic surface of the infected erythrocyte. These two related findings could play important roles in the microvascular stasis characteristic of acute B. bovis infection.

Babesiabovis — Analysis and vaccination trial with the cryoprecipitable immune complex

Plasma samples from cattle recovering from acute Babesia bovis infection contain cryoprecipitable immune complexes (IC). Production of bovine and rabbit antisera to IC and subsequent serological assays indicated IC contained antigens of both babesial and erythrocytic origin. Vaccination of naive cattle with IC produced low titred antibody to B. bovis but the vaccinates did not survive challenge with a heterologous strain of B. bovis.