Babesia bovis: isolation of a protective antigen by using monoclonal antibodies

Abstract

Three distinct monoclonal antibody-producing hybridomas have been produced against a partly purified protective fraction of Babesia bovis. All three stain the parasite or infected erythrocytes or both in precise and different manners when fluorescent-antibody techniques are used. The relevant antigens for each monoclonal antibody were isolated by immunoadsorption, their native molecular weights being 1.3 X 10(6), 180 X 10(3), and 44 X 10(3). Each antigen reacted in serological assays with homologous and heterologous bovine antisera to B. bovis. Susceptible splenectomized calves were immunized twice, 4 weeks apart, with the respective antigens and were challenged with virulent homologous organisms 2 weeks later. Strong protective immunity was induced by the antigen with a molecular weight of 44 X 10(3), but no significant protection was induced by either of the other two antigens.

PROTECTIVE ANTIGENS IN FRACTIONS OF ADULT NEMATOSPIROIDES DUBIUS

“…25,000 and 65,000) (unpublished observations). High molecular weight also enhanced the efficacy of protozoan parasite molecules and complexes as vaccines (Wright et aL, 1983b).…”

Sequence Conservation of the 12D3 Gene in Mexican Isolates of Babesia bovis

“…Babesia bovis 12D3 antigen has been reported as a 41 kDa glycoprotein that is mainly localized in the apical complex of the merozoite, although it may also diffuse in the stroma of the infected erythrocyte (Harper et al, 1996; Court et al., 1998). 12D3 has been classified as a non‐immunodominant antigen since immunochemical assays performed with the purified protein have shown weak recognition signals when exposed to polyclonal antibodies present in the serum of infected or immunized cattle (Wright et al., 1983, 1985, 1992). 12D3 mature protein is mainly soluble and it is released in the cytoplasm of the infected erythrocyte during parasite division (Harper et al, 1996; Court et al., 1998).…”

Production and Characterization of a Panel of Monoclonal Antibodies for the Identification of Antigens of Babesia bovis

“…For this reason, precise, sensitive, and specific diagnostic methods are essential. However, Babesia antigens that are produced either from infected blood or parasitized culture suspensions are unsatisfactory, resulting in cross-reactions with other Babesia species or in some instances even non-specific reactions (Wright et al, 1983).…”