ABSTRACT
Levels of platelets and other hematological values were monitored in 21 Saimiri and 12 Aotus monkeys over a period of three weeks post-infection with monkey-adapted Indochina CDC-1 strain of Plasmodium falciparum. In both Saimiri sciureus boliviensis and Aotus nancymai karyotype-1 monkeys the severest thrombocytopenia was observed at 14 days post-infection coinciding with peak parasitemia, neutropenia, lymphocytosis, and anemia associated with severe hemoglobinemia and elevated fibrinogen degeneration products(FDP's). MCH and MCV profiles in Aotus monkeys decreased with ascending parasitemia. In contrast, these parameters in Saimiri were characterized by a significant compensatory increase correlating with parasitemia. In general, thrombocytopenia was one of the earliest clinical manifestations of the infection with the platelets returning to normal levels shortly after peak parasitemia at 14 days. Platelet kinetics had a strong correlation with hematologic and parasitologic values in the Aotus model. No consistent associations were observed between platelet kinetics and other parameters in the Saimiri model. These data indicate that the Aotus model for malaria is more predictable than the Saimiri. Further, platelet turnover rates and recovery provide a useful prognostic parameter during malaria infection. The results are discussed in relation to the value of the two species of monkeys as models for the pathogenesis of human malaria.
Subject(s)
Aotus trivirgatus , Disease Models, Animal , Malaria, Falciparum/blood , Platelet Count , Saimiri , Animals , Erythrocyte Count , Hemoglobins/analysis , Leukocyte Count , MaleABSTRACT
Soluble Plasmodium falciparum polypeptides, affinity-purified from culture supernatant fluids using sequential immunoadsorptions employing both monoclonal and polyclonal antibodies, induced protective immunity against experimental falciparum malaria in Peruvian Aotus nancymai monkeys. Susceptible monkeys were vaccinated with polypeptides affinity-purified from supernatant fluids of P. falciparum Indochina I/CDC cultures. Eighteen animals (6 immunized with purified antigens plus adjuvants, 6 injected with only the adjuvant preparation, and 6 untreated) were challenged with whole blood containing monkey-adapted virulent organisms of the Indochina I/CDC strain. Selected hematologic, serologic and parasitologic profiles served as potential indicators of protection. This immunogen, when fortified with an aluminum hydroxide/Quil-A saponin adjuvant combination, elicited good antibody responses to major P. falciparum antigens. Protection in vaccinated animals was evidenced by a significantly limited reduction in hematocrit and hemoglobin levels and a relatively moderate course of infection after homologous needle-challenge with Aotus monkey-adapted P. falciparum parasites.
Subject(s)
Antigens, Protozoan/immunology , Malaria/prevention & control , Plasmodium falciparum/immunology , Protozoan Vaccines , Animals , Antibodies, Protozoan/biosynthesis , Antigens, Protozoan/chemistry , Antigens, Protozoan/isolation & purification , Aotus trivirgatus , Blotting, Western , Chromatography, Affinity , Electrophoresis, Polyacrylamide Gel , Female , Hematocrit , Hemoglobins/analysis , Male , Molecular Weight , Vaccination/adverse effectsABSTRACT
A reagent conservative Dot-enzyme immunoassay (Dot-EIA) was developed primarily for canine babesiosis caused by Babesia canis. The technique is simple, specific, and sensitive. All steps were carried out at room temperature. Strong agreement was observed between Dot-EIA and the conventionally used indirect immunofluorescence test. The procedure is adaptable to other protozoal disease, e.g., bovine babesiosis and human malaria.
