Liver fluke antigens derived from juvenile fasciolo organisms

摘要

It has been a problem to combat the liver fluke parasite in ruminant animals such as sheep and cattle. The present invention provides antigens having specificity for the juvenile stage of the organism. They are defined as obtainable from juvenile Fasciola, preferably F. hepatica, organisms by either of two closely related methods. In both methods crude antigen is extracted from juvenile Fasciola organisms and used to raise an antiserum (by injection into rabbits for example). The antiserum is then reacted with adult Fasciola antigens. An adult antigen--adult antibody complex is formed, leaving the other components of the antiserum including juvenile specific antibodies. The juvenile specific antibodies are separated from the complex by spinning and "Millipore" filtering. This is followed either by (1) separating IgG components, including specific IgGs, e.g. on a protein A column or (2) subjecting the post- absorption antiserum to immunoelectrophoresis against crude juvenile- specific antigens, and raising an antiserum against the antigen component of this complex. After step (1) or (2), the juvenile-specific antibodies (purified IgGs or antiserum) are used to purify crude juvenile Fasciola antigens. It is possible to omit step (1), in which case post-absorption antiserum is immunoglobulins of all classes are used in this step. Free antigen is liberated from the material bound to the column.P PThe invention also includes a fragment of the antigen carrying a juvenile-specific antigenic determinant, a vaccine comprising the antigen or fragment thereof together with an adjuvant or carrier, and monoclonal and polyclonal antibodies to the antigen or antigenic determinant.