Initial characterization of cryoprecipitates in cattle recovering from acute Babesia bovis (Argentina) infection.

The plasma of cattle recovering from severe babesia bovis infection contained cold precipitable protein which consisted of immune complexes formed in antibody excess. The major immunoglobulin in the complexes was IgM although IgG1 and IgG2 were also present at lower concentrations. In addition, fibrinogen, alpha 2 macroglobulin and C3 component of complement were detected. As the complexes were produced after parasiteamia fell below the detectable level and the inflammatory response to B. bovis was waning, the complexes did not appear to have much pathological significance.

Bovine babesiosis: the immunization of cattle with fractions of erythrocytes infected with Babesia bovis (syn B. argentina).

Soluble antigen which protected susceptible cattle against challenge with Babesia bovis was extracted from B. bovis-infected erythrocytes by sonic disintegration and separation of the soluble from the insoluble matter by ultracentrifugation. The material was then fractionated by the precipitation of fibrinogen-like proteins. The precipitate contained the babesial antigens that were located on the stroma of the infected erythrocytes. Antigen originally located on the parasite remained in solution. Both fractions conferred protection on splenectomized calves against challenge with B. bovis. However, the fraction containing the parasite antigens appeared to have more potential for development as a killed vaccine because it was not heavily contaminated with antigenic material from bovine erythrocytes.

Babesia bovis (Argentina): studies of plasma lipids and lipoproteins during acute infections in cattle.

Preliminary studies have demonstrated changes to the lipid metabolism of cattle acutely infected with Babesia bovis. Total lipid, total cholesterol, and phospholipids decreased significantly during infection. Associated with this was a decrease in concentration of serum lipoproteins and a loss of their electrophoretic heterogeneity. These changes are discussed in relation to the pathophysiological changes during infection.

Babesia bovis (Argentina): analysis of paracoagulation proteins in acutely infected cattle.

The proteins in plasma and serum from cattle infected with Babesia bovis that react with protamine sulphate and ethanol have been characterized. Their sizes and chain structures suggest they are intermediates in the conversion of fibrinogen to cross-linked fibrin. In addition, comparison with reference proteins and in vitro systems strongly indicate the proteins are, in the main, the products of thrombin activation in vivo and not those of fibrinolysis.

Babesia bovis (argentina): analysis of fibrinogen-like proteins during infection.

Fibrinogen and fibrinogen-like proteins (FLP) were isolated from plasma and serum of cattle acutely infected with Babesia bovis. The sizes and chain structures of these proteins were examined and clotting assays performed. The results indicated that the blood was in a hypercoagulable state due mainly to enhanced production of hydrogen bonded fibrin and offset partly by slight inhibition of chain cross-linking. The latter appeared due to a Factor XIII inhibitor. Reduction of A alpha chains of plasma FLP was not evident, nor could lower molecular weight remnants be regularly detected strongly suggesting that fibrin(ogen) lysis rarely occurred. Similarly the size and chain structure of the majority of noncoagulable FLP of serum was consistent with their being the product of coagulation and not fibrinolysis. Only in heavily infected splenectomized cattle were products from lysed cross-linked fibrin detected and these constituted only about 3% of total serum FLP.

Babesia bovis (argentina): components of the cryofibrinogen complex and their contribution to pathophysiology of infection in splenectomized calves.

A cryofibrinogen complex, found in the plasma of cattle acutely infected with Babesia bovis (argentina), was characterized. The fibrinogen-like proteins of the complex were isolated and the structure of their polypeptide chains analysed. In general, the chain structure was similar to that of soluble non-crosslinked fibrin (fibrinogen) although chains indicating some degree of fibrin crosslinking were often detected. Only rarely did the chain structure suggest that fibrinolysis occurred. It was concluded that the complex was produced by activation of the coagulation system but that fibrinolysis did not occur to any marked degree. The complex was implicated in assistance to the sludging of erythrocytes in the internal organs which is a feature of the pathogenesis of the disease.

Babesia bovis (= argentina): changes in erythrophylic and associated proteins during acute infection of splenectomized and intact calves.

Saline eluates were prepared from sucrose-washed erythrocytes of cattle infected with B. bovis (= argentina). Fibrinogen, plasminogen and IgG2 were constituent proteins of the eluates and all three proteins increased in concentration during infection. The significance of the protein changes and their contribution to coagulation and fibrinolysis during infection are discussed.

Babesia bovis (argentina): observations of coagulation parameters, fibrinogen catabolism and fibrinolysis in intact and splenectomized cattle.

The results of this paper indicate that cattle infected with B. bovis (argentina) have a markedly altered and activated coagulation system. A degree of thrombin activation occurs due partly to release of thromboplastin-like substances from lysed erythrocytes but due primarily to activation of kallikrein by babesial proteases. This produces a hyperfibrinogenaemia, particularly in intact cattle, with soluble fibrin complexes constituting up to one-third of the total fibrinogen concentration. High molecular weight non-coagulable fibrinogen-like proteins are detected terminally but more so in splenectomized cattle. Plasminogen concentration decreases in splenectomized but not intact cattle while low molecular weight fibrinogen degradation products are not easily detected. It is suggested that a hypercoagulable intermediate state with little or no fibrin deposition occurs rather than terminal disseminated intravascular coagulation.

Babesia argentina: observations on the immunogenicity of the cryofibrinogen complex.

Rabbit antisera were prepared against the soluble and insoluble fractions of a cryofibrinogen complex that formed in plasma of cattle acutely infected with Babesia argentina. Analyses of the rabbit antisera indicated that the cryofibrinogen complex contained proteins from erythrocytes and parasites as well as fibrinogen and related proteins.

A cold precipitable fibrinogen complex in the plasma of cattle dying from infection with Babesia argentina.

Plasma from cattle dying from infection with Babesia argentina formed a cold precipitable gel when stored at 4 degrees C. Immunodiffusion and electrophoresis showed the soluble phase of the gel to consist mainly of a fibrinogen-like protein with small amounts of other plasma proteins. Gel filtration and specific clotting assays demonstrated a wide molecular weight spectrum of fibrinogen-like proteins, most of which appeared to be soluble fibrin in either monomer or complex forms. The possibility that proteolytic enzymes might be responsible for the formation of the gel is discussed.