Richard G. Strout

Major histocompatibility (B) complex effects on acquired immunity to cecal coccidiosis

The influence of the major histocompatibility (B) complex on acquired immunity to the avian coccidium Eimeria tenella was studied in 217 F4 segregants (B2B2, B2B5, B5B5) of a cross between inbred lines 61 (B2B2) and 151 (B5B5) and segregating haplotype combinations of UNH105 (B23B23B23B24, B24B24), a noninbred line of New Hampshire chickens. Chickens were immunized at 6 weeks of age with 500 oocysts daily for 5 days, then challenged 14 days later with 10000 oocysts. Responses to infection were evaluated by cecal lesion scores, body weight gain, delayed wattle reaction (DWR), and spleen weight. The F4 segregants of genotypes B2B5 and B5B5 exhibited greater immunity to challenge than B2B2 chickens. B5B5 chickens showed a significantly greater DWR following immunization and larger spleens 6 days after the challenge than either of the other genotypes. However, both BIBS and B5B5 chickens demonstrated significantly lower lesion scores than B2B2 chickens. There were no significant differences in weight gain among these genotypes. Among 139 line UNH105 segregants, B23B23 hosts had significantly lower lesion scores than B24B24 chickens. No other differences in immune response among line UNH105 genotypes were detected.

Eimeria tenella: accumulation and retention of anticoccidial ionophores by extracellular sporozoites.

Abstract Extracellular sporozoites of Eimeria tenella were incubated at either 25 or 40 C in the presence of 14 C-lasalocid or 14 C-narasin, both anticoccidial ionophores. Liquid scintillation analysis shows that both ionophores are accumulated by the sporozoites outside their host cell. The relative degree of retention was significantly different for the two incubation temperatures and the concentration of lasalocid retained was consistently greater than that of narasin.

In vitro cultivation of Eimeria acervulina (Coccidia)

Abstract Eimeria acervulina oocysts were sterilized with 50 ppm chlorine and viable sporozoites were released mechanically with the aid of trypsin and bile. These sporozoites, when suspended in the appropriate cell culture nutrient, were used as inoculum for chick embryo kidney, chick embryo fibroblast, mouse fibroblast, human amnion, and HeLa cell cultures. Infection of the host cell by sporozoites occurred in cultures of each cell type. Apparent cell infection occurred as early as one hour post inoculation, and forms recognized as trophozoites were observed at 18 to 24 hours. Further development failed to occur.

Fatty acid composition of cultured aortic cells from white carneau and show racer pigeons

Summary Cell cultures have been established from aortic intimal tissue of White Carneau and Show Racer pigeons. Analyses of the higher fatty acid (> laurate) compositioni of the cultures revealed the absence of arachidonate in aortic cells from atherosclerosis-susceptible White Carneaux. A metabolic defect in the formation of arachidonate by these cells is suggested since aortic cells cultured from atherosclerosis-resistant Show Racers have the normal amount of arachidonate.

Eimeria tenella: effect of narasin, a polyether antibiotic on the ultrastructure of intracellular sporozoites.

Abstract Eimeria tenella sporozoites were inoculated into cultures of chick kidney cells in the presence of 0.01 or 0.1 μg/ml of narasin and incubated at either 40 or 30 C for 24 hr. Electron microscopic examination revealed that either concentration of this polyether ionophore caused extensive ultrastructural damage to the intracellular sporozoite at 40 but not at 30 C, indicating that the severity of the coccidiocidal effect is influenced by temperature. The effect of 0.01 μg/ml monensin on the intracellular parasite was similar to that of narasin, suggesting a common destructive mechanism. The host cells were unaffected by 0.01 μg/ml of narasin at either temperature and by 0.1 μg/ml at 30 C, indicating that the polyether ionophores can be selectively lethal for the parasite. However, when the host cells were treated with 0.1 μg/ml narasin and incubated at 40 C, ultrastructural abnormalities were evident. The results suggest that the coccidiocidal effect of the polyether ionophorous antibiotics may be a general osmotic phenomenon.

Eimeria tenella: Screening of chemotherapeutic compounds in cell cultures☆

Abstract Preliminary studies indicate that screening for anticoccidial activity is feasible in a cell culture system. Ten compounds shown to be active in vivo were tested against a field strain of Eimeria tenella (from the cecum of the domestic chicken) cultivated in primary embryonic chick kidney cells grown in Leighton tubes. The drugs, added to the culture nutrient containing the sporozoite inoculum, were prepared at levels of 100, 10, and 1 μg/ml. Because cytotoxity occurred with dianemycin, monensin, nigericin, antibiotic X-206, and to a lesser extent with antibiotic A-204, the 100 μg/ml suspensions of these insoluble drugs were filtered through a millipore filter (0.22 μm), thereby reducing not only cytotoxicity but the final concentration as well. Amprolium was readily soluble; buquinolate, decoquinate, glycarbylamide, and nicarbazin were largely insoluble and except for nicarbazin at the 100-μg level, did not appear to affect the cells adversely. In addition, two compounds known to be inactive against E. tenella in vivo were tested also; both were soluble and neither was cytotoxic. Cultures were fixed and stained after 72 hr of incubation when many mature first generation and early second generation schizonts appeared in control preparations, and at 96 hr when mature second generation stages were present. The results showed that all of the ten compounds active in vivo were also active in vitro within a 72-hr period of development, while neither of the two inactive materials was effective. Activity was manifested by an easily detected reduction or elimination of schizogony when compared with untreated controls, the absence of any second generation development, or by the appearance of abnormal sporozoites, trophozoites, or immature schizonts. In vitro screening for anticoccidial activity appears to be an effective, rapid method which requires only microgram quantities of the materials to be tested.

Glycoconjugates of the intestinal epithelium of the domestic fowl (Gallus domesticus): A lectin histochemistry study

SummaryA lectin histochemical study was performed on formalin-fixed paraffin-embedded tissues of duodenum, jejunum, ileum, caecum and colon from six fasted and six non-fasted 8-week-old chickens (Gallus domesticus). The purpose of this study was to identifyin situ the pattern of carbohydrate residues present on the luminal surface of the intestinal epithelium. Ten biotinylated lectins with different sugar specificities were used as probes, and avidin—biotin—peroxidase complex (ABC) was used as a ‘visualant’. The most significant finding was the binding pattern ofLens culinaris agglutinin to various segments of the intestines. The luminal surface of the small intestinal epithelium did not stain with this lectin. In the colon the luminal surface was lightly stained, while the caecal luminal surface was intensely stained. Throughout the intestine the luminal surface stained withCanavalia ensiformis agglutinin,Ricinus communis agglutinin-I and wheatgerm agglutinin, but it did not stain withDolichos biflorus agglutinin. These findings indicated that, throughout the intestine, the luminal surface contains glycoconjugates with eitherN- orO-linked glycoprotein, or both, with terminal non-reducing β-galactosyl and sialyl residues. Furthermore, the caecal surface is rich inN-linked glycoproteins with an α-(1→6)-linked fucosyl residue near the glycosidic linkage. The potential significance of these observations and the role of glycoconjugates in host—parasite interaction (i.e.Eimeria sp. versusGallus domesticus) are discussed.

Mitochondrial involvement in lipid vacuole formation in cultured aortic cells from white carneau pigeons

Summary Lipid vacuoles in cells cultured from aortic intimal tissue of atherosclerosis-susceptible White Carneau pigeons appear to originate from mitochondria which are enlarged, misshapen, and lack ATP-ase activity. Analyses of the fatty acid compo-sition of the mitochondrial fraction of White Carneau cells revealed only traces of arachidonate. Significantly larger amounts of arachidonate were detected in the mitochondrial fraction of cells cultured from aortic intimal tissue of atherosclerosis-resistant Show Racer pigeons, and lipid vacuoles were not apparent in these cells. The formation of lipid vacuoles from mitochondria in White Carneau cells in vitro is postulated to result from a genetically defective mitochondrial structure which becomes manifest as the intimal cells proliferate rapidly in tissue culture.

Survival and growth of vaccinated, medicated and untreated coho salmon (Oncorhynchus kisutch) exposed to Vibrio anguillarum☆

Abstract Vaccination and medication with terramycin resulted in increased survival of pen-reared coho salmon ( Oncorhynchus kisutch ) exposed to vibriosis in a Maine estuary. Mortality was significantly lower ( P

Schizonten und Merozoiten von Eimeria tenella in Makrophagen

ZusammenfassungDie Feinstruktur der Schizonten und Merozoiten von Eimeria tenella vom 5. und 6. Tag nach der Infektion wurde untersucht. Die Merozoiten weisen im allgemeinen keine wesentlichen Unterschiede in ihrem Feinbau gegenüber entsprechenden Stadien anderer Eimeria-Arten auf. In einem einzigen Fall erschien der Conoidapparat als ausstülpbare Papille. Schizonten und Merozoiten waren oft in großen Zellen eingeschlossen, die außer den Parasiten auch Erythrocyten in ihrem Cytoplasma enthielten. Diese Zellen können mit großer Wahrscheinlichkeit als Makrophagen angesehen werden. Während einige Parasitenstadien in diesen Wirtszellen normal strukturiert erschienen, zeigten andere Schädigungen, so daß sie nur noch an den für Eimeria-Stadien typischen Glykogeneinschlüssen zu identifizieren waren, die der Einwirkung der Makrophagen am längsten widerstehen.SummaryBy means of electron microscopy a study was made of the merozoites of Eimeria tenella from fifth and sixth day infections. E. tenella merozoites showed no essential differences from those of other species of Eimeria. In one instance we found a conoid apparatus that was equipped with an extrusible papilla. A great number of developmental stages was phagocytised and destroyed by macrophages. While the fine structure of the schizonts appeared morphologically normal, many merozoites were damaged or digested, and were identified only by the typical glycogen inclusions resisting the digestive process of the host cell.