United States Patent:  6,036,961

Assignee:  University Technologies International Inc. (CA)

Filed:  June 5, 1995

The invention provides vaccines and methods for preventing or treating intestinal protozoal infections in an animal. In particular, vaccines and methods for prevention or treatment of giardiasis are provided. The invention also encompasses methods of preparing and methods of use of novel toxins, antibodies, vaccine strains and compositions that result from or are used in these methods.

SUMMARY OF THE INVENTION

The invention provides vaccines and methods for preventing or treating intestinal protozoal infection in an animal, as well as novel toxins which may be used in said vaccines. Vaccines and methods for preventing or treating giardiasis, in particular, are also provided. The invention also encompasses methods of preparing and methods of use of novel toxins, antibodies, vaccine strains and compositions that result from or are used in these methods.

Accordingly, in one aspect, the invention provides vaccine strains of intestinal protozoa. A method of preparing these vaccine strains is also provided.

Another aspect of the invention is a vaccine composition comprising a vaccine strain of an intestinal protozoan. A cell free vaccine composition comprising a subunit or toxin of an intestinal protozoan is also provided, as is a method of preparing these vaccine compositions.

A further aspect of the invention is a method of preventing or treating infection by intestinal protozoa in an animal comprising administering to the animal an effective amount of a vaccine strain of the intestinal protozoa. A method of preventing or treating infection by an intestinal protozoan comprising administering a cell free composition comprising a subunit or toxin of the intestinal protozoan is also provided.

Yet another aspect of the invention is a toxin of an intestinal protozoan. A method of preparing the toxin is also provided, as are an antibody to the toxin and a method of passive immunization using the antibody.

Claim 1 of 16 Claims

1. A method of making a vaccine composition comprising a protectively immunogenic amount of an antigenic subunit of giardia obtained from a giardia strain cultured in media containing bile and an adjuvant comprising:

a) culturing a giardia strain in media containing bile;

b) separating said giardia from said media;

c) disrupting said separated giardia;

d) isolating at least one antigenic subunit which provides protective immunogenicity from said disrupted giardia; and

e) adding an adjuvant.

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