Eimeria Papillata Research Articles

Ameliorative Effects of Teucrium polium Leaves Ethanolic Extract on Liver Histopathology Induced by Eimeria papillata

Background: Teucrium polium is an herb utilized in traditional medicine for its biological activity. In the present study, T. polium leaves ethanolic extract (TPLEE) was investigated for its effects on coccidiosis resulting from Eimeria papillata infection in mice. Methods: In vivo, TPLEE (150 mg/kg) was administered for its antioxidant and hepatoprotective properties. The anticoccidial and anti-inflammatory effects of TPLEE were evaluated by measuring oocyst suppression and assessing liver histopathology, respectively. Result: Indicated that treatment with 150 mg/kg TPLEE led to oocyst suppression percentage of 91.2±4.1, similar to the efficacy of the reference drug amprolium (93.2±3.9) and was associated with a significant decrease in the number of developmental parasitic stages in jejunal sections. Infection with the parasite causes metabolic disturbance, inflammation and liver injury, as evidenced by histopathological changes such as Kupffer cell activation, vacuolated hepatocytes and increases in inflammatory cellular infiltration. In addition, infection led to a significant increase in malondialdehyde (MAD) and nitric oxide (NO) and a significant decrease in superoxide dismutase (SOD) and glutathione (GSH). The TPLEE showed significant hepatoprotective ability by improving the above parameters. TPLEE demonstrated both anticoccidial properties and the ability to alleviate preexisting liver damage caused by Eimeria infection.

Potential role of the methanolic extract for Olea europaea (stem and leaves) on sporulation of Eimeria papillata oocysts: In vitro study.

Many plants are efficient anticoccidial agents owing to their content of active chemicals. Drug-resistant Eimeria species have emerged as a result of excessive drug use. The current work aimed to investigate the oocysticidal activity (Eimeria papillata) of Olea europaea stem extract (OESE) and leaf extract (OELE) in vitro. The results of gas chromatography-mass spectrometry analysis for OELE and OESE showed the presence of 12 and 9 phytochemical compounds, respectively. Also, chemical examination revealed that the plant extracts are rich in phenols, flavonoids and tannins. Additionally, the best radical scavenging activity of OESE and OELE was at a concentration of 100 μg/ml, reaching 92.04 ±0.02 and 92.4±0.2%, respectively. The in vitro study revealed that concentrations of 200 mg/ml from OESE and OELE caused significant inhibition (100%) of process sporulation for E. papillata oocysts, in contrast to the other commercial products, which displayed varying degrees of suppression sporulation. Our findings showed that OESE and OELE have anticoccidial activity, which motivates further the conduction of in vivo studies in the search for a less expensive and more efficient cure.

Persea americana extract protects intestinal tissue from Eimeria papillata-induced murine Infection

Coccidiosis is the most prevalent disease-causing widespread economic loss among farm and domestic animals. Currently, several drugs are available for the control of this disease but resistance has been confirmed for all of them. There is an urgent need, therefore, for the identification of new sources as alternative treatments to control coccidiosis. The present work aimed to study the effect of the Persea americana extract (PAE) as an anti-coccidial, anti-oxidant, and anti-apoptotic modulator during murine intestinal Eimeria papillata infection. A total of 25 male mice were divided into five groups, as follows: Group1: Non-infected-non-treated (negative control), Group2: Non-infected-treated group with PAE (500 mg/kg b.w). Group3: Infected-non-treated (positive control), Group4: Infected-treated group with PAE (500 mg/kg b.w.), and Group5: Infected-treated group with Amprolium (120 mg/kg b.w.). Groups (3–5) were orally inoculated with 1 × 103 sporulated E. papillata oocysts. After 60 min of infection, groups (4 and 5) were treated for 5 consecutive days with the recommended doses of PAE and amprolium. The fact that PAE has an anti-coccidial efficacy against intestinal E. papillata infection in mice has been clarified by the reduction of fecal oocyst output on the 5th day post-infection by about 85.41%. Moreover, there is a significant reduction in the size of each parasite stage in the jejunal tissues of the infected-treated group with PAE. PAE counteracted the E. papillata-induced loss of glutathione peroxidase (GPx), superoxide dismutase (SOD), and total antioxidant capacity (TCA). E. papillata infection also induced an increase in the apoptotic cells expressed by caspase-3 which modulated after PAE treatment. Moreover, the mRNA expression of the goblet cell response gene, mucin (MUC2), was upregulated from 0.50 to 1.20-fold after treatment with PAE. Based on our results, PAE is a promising medicinal plant with anti-coccidial, anti-oxidant, and anti-apoptotic activities and could be used as a food additive.

Atividade antiparasitária in vitro do extrato etanólico das folhas de Anethum graveolens

ABSTRACT Natural products are safe environmentally friendly agents and have no negative impact on the environment, they can be used to combat parasitic diseases. Helminthiasis and coccidiosis are parasitic diseases that harm both health and the economy. This research aimed to see how Anethum graveolens leaves extract (AGLE) worked as an anti-parasitic modulator during oocyst sporulation of an Eimeria papillata infection. FT-IR phytochemical analysis revealed the presence of eight compounds. The time required to induce paralysis and death in worms at the highest concentration (200 mg/mL) was 4.57±0.26 and 5.22±0.10 min, respectively. In an in vitro study, AGLE (300 mg/ml) inhibited sporulation by approximately 100% after 72 and 96 hr. AGLE (200, 100, and 50 mg/ml), amprolium, DettolTM, and phenol induced variable inhibition levels at 96 hr of 5.54%, 1.01%, 37.33%, 81.33%, and 89.33%, respectively. Our findings suggest that AGLE has potent anthelmintic and anticoccidial properties that could be further developed into a novel therapeutic agent.

The Anticoccidial Effects of the Poultry Bile against Eimeria papillata Oocysts of Mice: In vitro Study

Background: Coccidiosis is a costly and wide-spread infectious disease in mammals that causes huge losses in the poultry industry worldwide. The present study was conducted to evaluate the potency of intact poultry gallbladder on the sporulation of Eimeria papillata oocysts of mice and to determine the best concentration for the activity of poultry bile on the inhibition of sporulation in oocysts. Methods: In this test, we used potassium dichromate solution (2.5%) as control group. Unpopulated oocysts were exposed (1 x 103/3 ml) to four concentrations of poultry bile (w/v; 10%, 25%, 50%, and 100%). It was incubated in petri dishes for 48, 72 and 96 hours at 25-29°C, with 60-80% humidity. The sporulation was examined under an inverted microscope at 40 x to confirm oocyst sporulation. Result: Showed through infrared spectroscopy of poultry bile that there are many expected active classes of chemical compounds. At a 100% concentration of poultry bile, it was able to inhibit the Eimeria papillata oocysts by about 98% in potassium dichromate solution. Also, it observed its ability to inhibit sporulation of oocysts in a dose-dependent manner at concentrations of 50%, 25%, and 10% of bile, the rate of inhibition was (71.7%, 33.11% and 19.88%), respectively. We found a direct relationship between inhibition and sporulation related to the increasing time period.

Morphological and molecular approaches for identification of murine Eimeria papillata infection

Oocysts recovered from Mus musculus were morphologically described and molecularly characterized using 18S rDNA and ITS1 regions. Sporulated oocysts had two layers and were sub-spherical measuring 20.76 (19.41–22.33) × 17.46 (15.44–19.15) μm with a length/width index of 1.18. Sporocysts were with stieda and substieda bodies with sporocystic residuum. Molecular data from both 18S rDNA and ITS1 regions revealed that the species under investigation is related to Eimeria papillata. The 18S rDNA sequences obtained in this investigation were identical to an E. papillata sequence from M. musculus found in GenBank. The sequence obtained from the ITS-1 region showed a slight difference from other sequences from E. papillata for the same region with a similarity percent of 97.2% to 100%. The AT content of the ITS1 region from the present study was found to be 53.1%. According to ITS1 data, 10 haplotypes were characterized with haplotype diversity (Hd) of 0.9271. Sequences of the ITS1 region from E. papillata were variable in 18 sites with 3 indels, of those variable sites 15 were transitions while 3 were transversions. Therefore; the ITS1 region is probably a good marker for differentiating different strains of Eimeria species in rodents.

Molecular characterization of the waterborne pathogens Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, Cyclospora cayetanensis and Eimeria spp. in wastewater and sewage in Guangzhou, China

BackgroundThe waterborne pathogens Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi and Cyclospora cayetanensis can cause intestinal diseases in humans. An understanding of their occurrence and transport in the environment is essential for accurate quantitative microbial risk assessment.MethodsA total of 238 influent samples were collected from four wastewater treatment plants (WWTPs) and 88 samples from eight sewer locations in Guangzhou, China. PCR-based tools were used to detect and genetically characterize Cryptosporidium spp., G. duodenalis and E. bieneusi. Eimeria spp. and Cyclospora spp. were also analyzed to assess the sources of Cryptosporidium spp., G. duodenalis and E. bieneusi in wastewater.ResultsThe overall occurrence rates in the WWTP and sewer samples were 14.3% (34/238) and 13.6% (12/88) for Cryptosporidium spp., 55.5% (132/238) and 33.0% (29/88) for G. duodenalis, 56.3% (134/238) and 26.1% (23/88) for E. bieneusi and 45.4% (108/238) and 47.7% (42/88) for Eimeria spp., respectively. Altogether, 11 Cryptosporidium species and genotypes, six G. duodenalis genotypes, 11 E. bieneusi genotypes and four C. cayetanensis were found, together with the presence of nine Eimeria species. The common occurrence of Cryptosporidium rat genotype IV, C. muris and Eimeria papillata and E. nieschulzi suggested that rodents were significant sources of the enteric pathogens detected in the wastewater samples.ConclusionsWhile the dominant Cryptosporidium spp. detected in the raw wastewater sampled in this study are not pathogenic to humans, the widely detected G. duodenalis assemblage A and E. bieneusi genotypes D and Type IV are well-known zoonotic pathogens. Further studies are needed to monitor the occurrence of these waterborne pathogens in WWTPs to better understand their transmission and environmental transport in China. Graphical

Anticoccidial and antioxidant activities of zinc oxide nanoparticles on Eimeria papillata-induced infection in the jejunum.

Nanomedicine has recently emerged as a better option for the treatment of various diseases. Here, we investigated the in vivo anticoccidial properties of zinc oxide nanoparticles (ZNPs). ZNPs were crystalline in nature, with a smooth and spherical surface and a diameter in the range of ~10–15 nm. The X-ray diffraction pattern was utilized to identify the crystalline property of the grown ZNPs, whereas field emission scanning electron microscopy was employed to check the size and morphology of the ZNPs. The data showed that mice infected with Eimeria papillata produced 29.7×103±1,500 oocysts/g feces on day 5 postinfection. This output was significantly decreased, to 12.5×103±1,000 oocysts, in mice treated with ZNPs. Infection also induced inflammation and injury of the jejunum. This was evidenced (1) through an increase in the inflammatory histological score, (2) through increased production of nitric oxide and malondialdehyde, and (3) through a decrease in both the glutathione level and goblet cell number in mice jejuna. All these infection-induced parameters were significantly altered during treatment with ZNPs. Our results indicate, therefore, that ZNPs have protective effects against E. papillata-induced coccidiosis.

Anti-Eimeria activity of berberine and identification of associated gene expression changes in the mouse jejunum infected with Eimeria papillata.

Plant-based natural products are promising sources for identifying novel agents with potential anti-Eimeria activity. This study explores possible effects of berberine on Eimeria papillata infections in the jejunum of male Swiss albino mice. Berberine chloride, when daily administered to mice during infection, impairs intracellular development and multiplication of E. papillata, evidenced as 60% reduction of maximal fecal output of oocysts on day 5 p.i. Concomitantly, berberine attenuates the inflammatory response, evidenced as decreased messenger RNA (mRNA) expression of IL-1β, IL-6, TNFα, IFNγ, and iNOS, as well as the oxidative stress response, evidenced as impaired increase in malondialdehyde, nitrate, and H2O2 and as prevented decrease in glutathione and catalase activity. Berberine also alters gene expression in the infected jejunum. On day 5 p.i., mRNA expression of 29 genes with annotated functions is more than 10-fold upregulated and that of 14 genes downregulated. Berberine downregulates the genes Xaf1, Itgb3bp, and Faim3 involved in apoptotic processes and upregulates genes involved in innate immune responses, as e.g., Colec11, Saa2, Klra8, Clec1b, and Crtam, especially the genes Cpa3, Fcer1a, and Mcpt1, Mcpt2, and Mcpt4 involved in mast cell activity. Additionally, 18 noncoding lincRNA species are differentially expressed more than 10-fold under berberine. Our data suggest that berberine induces hosts to exert anti-Eimeria activity by attenuating the inflammatory and oxidative stress response, by impairing apoptotic processes, and by activating local innate immune responses and epigenetic mechanisms in the host jejunum. Berberine has the potential as an anti-Eimeria food additive in animal farming.

Anti-coccidial and anti-apoptotic activities of palm pollen grains on Eimeria papillata-induced infection in mice

The present work aimed to study the effect of palm pollen extract (PPE) as an anticoccidial and anti-apoptotic modulator during the course of murine intestinal Eimeria papillata infection. The fact that PPE has an anticoccidial efficacy against intestinal E. papillata infection in mice has been clarified by the reduction of faecal output of oocysts on day five post infection from 49.5 × 103 to 34 × 103 oocyst/g. Moreover, the number of intracellular eimerian stages of zygots and developing oocysts decreased by about 89% and that of schizonts and gamonts to 42% and 72%, respectively. E. papillata infection also induced an increase in the number of apoptotic cells from 17.5 to 122.8 apoptotic nuclei/10 villous crypt units (VCU). In addition, it caused a state of systemic inflammatory response as revealed by an elevation in levels of the pro-inflammatory biomarkers, inducible nitric oxide synthase (iNOs) and tumor necrosis factor alpha (TNF-α) from 5.3 and 78.3 to 33 pmol ml−1 and 96.3 pg ml−1 in blood, respectively, with concurrent duplication in the total leucocytic number. Upon treatment of infected mice with the aqueous PPE, the activity of iNOs was reduced by 55% and the level of TNF-α was decreased by 30%. Moreover, the total leucocytic count was significantly reduced from 9.05 × 103 to 7.8 × 103 cells/mm3. Based on our results, PPE showed both anti-coccidial, anti-inflammatory and anti-apoptotic activities. So it can be used in developing new herbal medicine against animal coccidiosis and may be suitable agent for treating eimeriosis associated inflammatory response.

Goblet Cells and Mucin Related Gene Expression in Mice Infected with Eimeria papillata

Coccidiosis causes considerable economic loss in the poultry industry. The current study aimed to investigate the response of goblet cells as well as the induced tissue damage during Eimeria papillata infection. Mice were infected with sporulated E. papillata oocytes. On day 5 postinfection, the fecal output was determined. Also, the jejunum was prepared for the histological, histochemical, and molecular studies. Our results revealed that the intestinal coccidian infection with E. papillata induced a marked goblet cell hypoplasia and depleted mucus secretion. Also, the infection was able to alter the jejunal architecture and increased the apoptotic cells inside the villi. In addition, the real-time PCR results indicated that the inflammatory cytokines: TNF-α, iNOS, IFN-γ, and IL-1β, were significantly upregulated. In contrast, the mRNA expression patterns of IL-6 in response to E. papillata infection did not differ significantly between control and infected mice. Moreover, the mRNA expression of TLR4 was significantly upregulated, whereas the expression of MUC2 is significantly downregulated upon infection. Further studies are required to understand the regulatory mechanisms of goblet cells related genes.

Antioxidant, hepatoprotective, and ameliorative effects of Azadirachta indica on Eimeria papillata-induced infection in mice

Azadirachta indica (neem) is used in traditional medicine for its pharmacological properties. Here, we investigated the effects of neem on the outcome of coccidiosis caused by Eimeria papillata in mice. Coccidiosis was induced by infection of mice with 103 sporulated oocysts of E. papillata. The methanolic extract of neem (Azadirachta indica) leaves (500 mg/kg) was used in vivo for its antioxidant and hepatoprotective properties. Anticoccidial and anti-inflammatory activities of neem were determined through oocyst output and liver histopathology, respectively. The data showed that mice infected with E. papillata revealed an output of about 6.5×105 oocysts per gram faeces on day 4 postinoculation (p.i.). This output is significantly decreased to about 2.7×105 oocysts in neem-treated mice. Infection caused a marked liver injury as indicated by histopathological alterations as well as the significant increase in liver aspartate aminotransferase (AST), alanine aminotransferase, alkaline phosphatase (ALP) and bilurubin. Also, infection induced a significant increase in nitric oxide (NO) and malondialdehyde (MAD), and a significant decrease in glutathione (GSH). The methanolic extract of A. indica leaves showed a significant (P ≤ 0.05) hepatoprotective potential by improving the above mentioned parameters. Based on these results, it is concluded that A. indica leaves contain potent antioxidant compounds that could offer protection against hepatotoxicity as well as ameliorate preexisting liver damage and oxidative stress conditions. Key words: Neem, liver, Eimeria papillata, oxidative stress, mice.

Role of Phoenix dactylifera in ameliorating Eimeria papillata-induced hepatic injury in mice

Phoenix dactylifera (Date) is used in traditional medicine for its pharmacological properties. Here, we investigated the effects of Khodary date fruit on the outcome of coccidiosis caused by Eimeria papillata in mice. Coccidiosis was induced by infection of mice with 1.5 × 103 sporulated oocysts of E. papillata. The aqueous extract of date fruit (4 ml/kg) was used in vivo for its hepatoprotective properties. Anticoccidial and anti-inflammatory activities of date fruit were determined through oocyst output and liver histopathology, respectively. The data showed that mice infected with E. papillata revealed an output of about 8.7 × 103oocysts per gram faeces on day 4 post -inoculation (p.i.). This output significantly decreased to about 6.7 × 103 oocysts in date fruit-treated mice. Infection caused a marked liver injury as indicated by histopathological alterations as well as the significant increase in liver glutamic pyruvate transaminase (GPT) and alkaline phosphatase (ALP). Also, infection induced a significant increase in total protein and total lipids. The aqueous extract of P. dactylifera fruit showed a significant (P ≤ 0.05) hepatoprotective potential by improving the aforementioned parameters. Based on these results, it is concluded that date fruit could offer protection against hepatotoxicity as well as ameliorate preexisting liver damage. Key words: Date fruit, liver, Eimeria papillata, mice.

The potential role of Phoenix dactylifera on Eimeria papillata-induced infection in mice

Coccidiosis is a common infectious disease in poultry causing major economic losses. Here, we investigated the effect of Khodary date fruit aqueous extract (4 ml/kg) on the outcome of coccidiosis caused by Eimeria papillata in Swiss Albino mice. Date fruit extract was able to decrease the intracellular development by lowering the faecal output of E. papillata oocysts from 8.7 ± 0.5 × 10(3) to 6.6 ± 0.4 × 10(3) oocysts per gram faeces. Also, date extract caused a great diminish in body weight of infected mice from 19.3 to 3.2 %. The number of parasitic stages in the intestinal villi of the infected mice was reduced to about 52 % after treatment with date extract. The infection was associated with marked histopathological lesions of the murine jejunum in the form of inflammation, vacuolation of the epithelium, and destruction of some villi. Also, the number of goblet cells within the infected villi was significantly lowered (P ≤ 0.05). These changes lead to an oxidative damage of the infected tissue. Moreover, infection induced a disturbance in both protein and carbohydrate content in the infected mice. Treatment of mice with date extract could improve the above-studied parameters. On the basis of the above results it can be hypothesized that date fruit can protect against coccidiosis-induced infection, this hypothesis can be revealed by the anti-inflammatory activity of date protecting host tissue from injuries induced by the parasite, and hence it is recommended to be used as an excellent food additive.

English

Electromagnetic radiation (EMR) produced by many telecommunication systems, has short and long term biological effects on living cells. The aim of this study was to investigate the influence of EMR on the outcome of coccidiosis induced by Eimeria papillata. Oocysts from E. papillata infected mice were exposed to the EMR in the form of gamma rays, ultraviolet rays and radiations emitted from the mobile phone. Sporulation rate, oocysts shedding as well as the histological alterations in jejunum of mice irradiated with oocysts exposed to EMR were determined. Oocyst output was reduced in mice exposed to EMR. The jejunum histopathology was improved after inoculation of mice with irradiated oocysts. We suggest that EMR has anticoccidial activities and its application could serve as an alternative to the anticoccidial drugs currently used in poultry production.   Key words: Electromagnetic radiation, Eimeria papillata, mice.

Anticoccidial and antiinflammatory activity of garlic in murine Eimeria papillata infections

Coccidiosis with the protozoan parasite Eimeria as the infectious agent causes enormous economic losses, particularly in poultry farms. Here, we investigated the effects of garlic on the outcome of coccidiosis caused by Eimeria papillata in male Balb/c mice. The data showed that mice infected with E. papillata revealed an output of 3260±680 oocysts per gram faeces on day 4 p.i.. This output is significantly decreased to 1820±415 oocysts in garlic-treated mice. Infection also induced inflammation and injury of the liver. This was evidenced (i) as increases in inflammatory cellular infiltrations, dilated sinusoids, and vacuolated hepatocytes, (ii) as increased mRNA levels of inducible nitric oxide synthase (iNOS) and of the cytokines interferon gamma (IFN-γ), and interleukin-6 (IL-6), (iii) as increased plasma levels of alanine and aspartate aminotransferases, alkaline phosphatase, γ-glutamyl transferase and total bilirubin, (iv) as increased production of nitric oxide derived products (nitrite/nitrate) and malondialdehyde, and (v) as lowered glutathione levels and decreased activities of catalase and superoxide dismutase, respectively. All these infection-induced parameters were significantly less altered during garlic treatment. In particular, garlic counteracted the E. papillata-induced loss of glutathione and the activities of catalase and superoxide dismutase. Our data indicated that garlic treatment significantly attenuated inflammation and injury of the liver induced by E. papillata infections.

Phylogenetic relationships among rodent Eimeria species determined by plastid ORF470 and nuclear 18S rDNA sequences

Phylogenetic analyses for 10 rodent Eimeria species from different host genera based on plastid ORF470 and nuclear 18S rDNA sequences were done to infer the evolutionary relationships of these rodent Eimeria species and their correlation to morphology and host specificity. The phylogenies based on both data sets clearly grouped the 10 rodent Eimeria species into two major lineages, which reflect more their morphological differences than host specificity. Species in lineage A have spheroidal to subspheroidal sporulated oocysts, are similar in size (18–29×17-23; x=22×20 μm), have an oocyst residuum and one-two polar granules; these include Eimeria albigulae ( Neotoma), Eimeria arizonensis (Peromyscus, Reithrodontomys), Eimeria onychomysis ( Onychomys) and Eimeria reedi ( Perognathus). Species in lineage B, including Eimeria falciformis ( Mus), Eimeria langebarteli ( Reithrodontomys), Eimeria nieschulzi ( Rattus), Eimeria papillata ( Mus), Eimeria separata ( Rattus) and Eimeria sevilletensis ( Onychomys) have different shapes (ovoid, ellipsoid, elongated ellipsoid, etc.), differ greatly in size (10–27×9–24; x=19×16 μm) and all lack an oocyst residuum. Thus, The oocyst residuum was the most determinant feature that differentiated the two lineages. The accession numbers of ORF470 of E. albigulae, E. arizonensis, E. falciformis, E. nieschulzi, E. onychomysis, E. papillata, E. reedi, E. separata, E. sevilletensis, E. langebarteli are AF311630–AF311639 and 18S rDNA of E. langebarteli, E. papillata, E. reedi, E. separata, E. sevilletensis are AF311640–AF311644.

Major histocompatibility complex class I- and II-deficient knock-out mice are resistant to primary but susceptible to secondary Eimeria papillata infections.

Two distinct mechanisms seem to function in reducing oocyst output during Eimeria papillata infections in mice. For naive mice, immunity was afforded by a T-cell-independent gamma-interferon (IFN-gamma) response mediated by natural killer (NK) cells. On reinfection, resistance was associated with T-cells and, to a lesser extent, perforin. To determine if antigen presentation with major histocompatibility complex (MHC) molecules was required to control oocyst production by NK cells during primary infection or by T-cells during secondary infection, mutant mice that lacked H2-IAbeta(b) (Abeta(b)-/-) or beta2-microglobulin (beta2m-/-) were used. Since MHC molecules are required for the maturation of alphabeta T-cells, Abeta(b)-/- and beta2m-/- mutant mice are also deficient in functional alphabeta+CD4+ or alphabeta+CD8+ T-cells, respectively. As compared with wild-type control mice, oocyst output by mutant mice was not significantly affected during primary infection, suggesting that the ability of NK cells to control parasite replication is not dependent on the expression of MHC molecules. On reinfection, differences were observed for mutant mice as compared with controls. Abeta(b)-/- mice were found to be more susceptible than beta2m-/- mice, suggesting that the alphabeta+CD4+ T-cell subset plays a greater role in resistance to reinfection than does the alphabeta+CD8+ T-cell subset. The mechanism of resistance depends on the immune status of the host and requires the coordinated interaction of both alphabeta+ T-cell subsets for optimal parasite control during subsequent infections.

Comparison of Four Murine Eimeria Species in Immunocompetent and Immunodeficient Mice

Factors associated with immune-mediated protection against coccidial parasites were examined in a series of experiments utilizing immunocompromised scid/scid(SCID) and scid/scid.beige/beige(SCID/Bg) mice, as well as immunocompetent BALB/c mice. Number of oocysts produced per g feces each day and prepatent and patent periods were assessed for 4 eimerian parasites (Eimeria papillata, Eimeria vermiformis, Eimeria falciformis, and Eimeria ferrisi) using the 3 murine strains. The number of infections required to elicit a protective immune response was also determined for each coccidial species in BALB/c mice. We report the first description of patent infections in inbred immunocompetent and immunodeficient mice infected with E. papillata. Results indicate that during primary infections, parasite replication is under partial immunological control for all Eimeria species. However, the control is mechanistically different for E. papillata because the adaptive immune response does not contribute to the control of primary infections. Both coccidial species infecting intestinal villar epithelial cells (E. papillata and E. ferrisi) were affected by the beige mutation using parasite output as an indicator, whereas E. falciformis, which infects intestinal crypt cells, is not. BALB/c mice were more resistant to challenge infections with upper intestinal parasites (E. papillata and E. vermiformis) in comparison to challenge infections with lower intestinal and cecal parasites (E. falciformis and E. ferrisi).

Specificity and cross-reactivity of hybridoma antibodies generated against Eimeria bovis sporozoites

Spleens from mice immunized with Eimeria bovis sporozoites were removed and the cells fused with mouse myeloma cells to produce hybridoma cell lines (HCLs). The resulting HCLs were examined for antibody (HAB) production against E. bovis sporozoites using an indirect immunofluorescent antibody test on air-dried sporozoites. Four fusions resulted in the production of 19 HCLs that produced HABs to E. bovis sporozoites. These 19 HCLs were further tested for reactivity with cell culture-grown merozoites of E. bovis and Sarcocystis cruzi of cattle; sporozites of Eimeria tenella from chickens, Eimeria meleagrimitis from turkeys, Eimeria papillata and Eimeria vermiformis from mice; and bradyzoites of S. cruzi from calves. Six HCLs produced HABs that reacted only with E. bovis sporozoites and were species specific/stage specific. Two HCLs produced HABs that reacted only with E. bovis sporozoites and merozoites, and were species specific/stage cross-reactive. Seven HCLs produced HABs that reacted with the sporozoites of the other Eimeria species examined and were species cross-reactive/stage specific. Four of the HCLs produced HABs that reacted with all organisms tested and were species cross-reactive/stage cross-reactive. The results of this study suggest the conservation of some antigens through-out developmental stages and genera of Eimeriorina.