Abstract: A subunit vaccine for Tritrichomonas foetus and method for preparing such vaccine for use in immunizing and treating animals is provided. The method disclosed involves separating out the antigens by centrifuging homogenized Tritrichomonas foetus cells, preferably at about 830.times.g for about 15 minutes, solubilizing the antigen with an nonionic detergent and completing with saponin. Topical administration, such as intravaginal or intrapretutial administration, of such vaccine preparation in conjunction with subcutaneous administration in combination with other adjuvants is effective to eliminate infection.

Abstract: Disclosed are vaccine compositions for use in developing protective immunity against infection by Plasmodium parasites. Soluble proteinaceous immunogens are isolated from the fluid culture medium of in vitro propagated plasmodial species parasites (e.g., P.falciparum) in mammalian erythrocyte culture supernatant or from washes, including hypotonic washes, of cultured erythrocytes parasitized by plasmodium. Immunogens so obtained have molecular weights in the range from about 35,000 daltons to about 85,000 daltons. Two principal immunogens of the invention have molecular weights of about 42,000 and 54,000 daltons, respectively. The water soluble immunogens are administered in a suitable carrier such as isotonic salt solution and in combination with a suitable adjuvant such as saponin or, preferably, aluminum hydroxide.

Abstract: Soluble antigen, specific for Babesia parasites, is isolated from growth media of Babesia-infected erythrocytes in cell culture and characterized, inter alia, by its ability to inhibit the capacity of specific Babesia serum antibodies to neutralize infectivity of Babesia merozoites in vitro. Antigen preparations provide immunologically active components useful for vaccination of animals against infection by Babesia parasites and may be employed in the preparation of diagnostic reagents.

Abstract: A method for quantitative propagation of hemotropic parasites, especially Babesia parasites, in vitro, Babesia-infected erythrocyte cultures are incubated in an environment of enhanced carbon dioxide tension wherein the culture medium overlay provides a barrier to oxygen transmission such that cellular hemoglobin is essentially maintained in its deoxy state. By varying environmental carbon dioxide tension, merozoite stages of the parasite are selectively reversibly induced to migration between residence in host cells or culture medium, rendering possible the isolation of infective antigenic merozoites in large quantities. Specific Babesia antigen is harvested in large quantity from the in vitro culture medium.