Mark C Jenkins

Agricultural Research Service, ERV, Texas, United States

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Publications (88)201.08 Total impact

  • Raymond H. Fetterer · Ruth C. Barfield · Mark C. Jenkins
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    ABSTRACT: RESUMEN Protección en pollos de engorde alojados con cohortes inmunizados contra Eimeria maxima y E. acervulina. El uso de vacunas con ooquistes vivos es cada vez más importante en el control de la coccidiosis aviar en pollos de engorde. El conocimiento de los mecanismos empleados cuando los pollos ingieren los ooquistes y adquieren inmunidad es importante para optimizar los métodos de aplicación de vacunas vivas. El presente estudio pone a prueba la hipótesis de que pollos no inmunizados previamente pueden ingerir ooquistes mediante el contacto con cama con ooquistes eliminados por pollos cohortes inmunizados. En el experimento 1, pollos de engorde de un día fueron alojados en corrales que contenían cama limpia. En el Ensayo 1, el 100% de los pollos en algunos de los corrales fueron inmunizados con 2.5 × 103 ooquistes de Eimeria acervulina, mientras que en otros corrales se inmunizó sólo al 75% de los pollos y el resto de cohortes dentro de los corrales no fueron inmunizados. Otros corrales contenían pollos que sirvieron como controles no inmunizados y no desafiados, o como controles no inmunizados y desafiados (NIC). En el día 21, las aves se expusieron a un desafío homólogo de 6 × 105 ooquistes. Un segundo ensayo idéntico se llevó a cabo, pero las aves fueron inmunizadas con 500 ooquistes de Eimeria maxima y se desafieron con 3 × 103 ooquistes de E. maxima. En el Experimento 2, el 100% de los pollos en algunos corrales se inmunizaron con 500 oocistos de E. acervulina, mientras que en otros corrales se inmunizaron ya sea el 75% o el 50% de las aves. En el día 14, las aves fueron desafiadas con 1 × 106 ooquistes. El ensayo 2 fue idéntico al ensayo 1, excepto que las aves fueron inmunizadas con 100 ooquistes de E. maxima y desafiados con 1 × 106 ooquistes. En todos los experimentos se midió el aumento de peso, la conversión alimenticia (FCR), carotenoides en plasma y conteos de ooquistes en la cama. En el Experimento 1, el nivel de protección en los grupos que contenían un 25% de los cohortes no inmunizados, de acuerdo a las determinaciones de aumento de peso, nivel de carotenoides, conversión alimenticia y por conteos de ooquistes en la cama, fue idéntico a los grupos que contenían 100% de los pollitos inmunizados. En el Experimento 2, los corrales donde 50% o 75% de las aves fueron inmunizados con E. maxima o con E. acervulina no estuvieron bien protegidos contra disminuciones en la ganancia de peso y de carotenoides plasmáticos, ni contra aumentos en los recuentos de ooquistes en la cama después del desafío en el día 14 en comparación con el grupo control no inmunizado y desafiado. Además, los corrales en donde se inmunizó al 100% de los pollos no estaban bien protegidos en comparación con el grupo control no inmunizado y desafiado y la resistencia a la infección por coccidiosis en pollos inmunizados fue menor que la resistencia observada en los pollos desafiados a los 21 días. En conjunto, estos resultados sugieren que cuando las aves se desafían después de los 21 días, los cohortes están protegidos de los efectos perjudiciales del desafío. Sin embargo, cuando el desafío se realizó a los 14 días, las aves cohortes no estuvieron bien protegidas. Los resultados apoyan la conclusión de que la protección contra la coccidiosis se transmite a las aves cohortes por el contacto con ooquistes en la cama diseminados por los pollos inmunizados, pero esta resistencia puede tomar 14 días para desarrollarse.
    Avian Diseases 03/2015; 59(1):98-105. DOI:10.1637/10958-101014-Reg · 1.11 Impact Factor
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    ABSTRACT: The uptake of amino acids is mediated by active transporters located on the basolateral and brush border membranes of intestinal epithelial cells. The current study investigated the expression of amino acid transporters (AAT) and other genes in the intestine of chicks infected with Eimeria maxima. At 7-day postinfection (PI), tissue from each intestinal segment (duodenum, jejunum, and ileum) was taken from birds inoculated with 3 × 10(3) oocysts/bird and processed to recover RNA. Analysis of gene expression was performed using real-time reverse transcription polymerase chain reaction (qRT-PCR). Results were given as relative expression using β2-microglobulin as an endogenous control. All the genes studied were expressed in three segments of the intestines, and expression of the genes was altered by infection with E. maxima. Even though the jejunum is considered the parasite's primary predilection site, there was no segment-related difference in expression of most of the genes studied. The antimicrobial peptide (LEAP2) was downregulated in all three segments of the intestine. The results also demonstrate that transporters associated with brush border membranes were downregulated while transporters associated with the basolateral membranes were upregulated and that E. maxima alters the expression of AAT and LEAP2 throughout the small intestine.
    Parasitology Research 09/2014; 113(10). DOI:10.1007/s00436-014-4114-3 · 2.33 Impact Factor
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    ABSTRACT: The current study investigates the use of irradiated oocysts to protect broiler chicks, raised on litter, from infection with multiple species of Eimeria. In order to determine the optimum radiation dose for each Eimeria species, 1-day-old chicks were immunized with oocysts of Eimeria maxima, Eimeria acervulina, or Eimeria tenella exposed to gamma radiation ranging from 0-500 Gy. The litter oocyst counts at 7 days postimmunization, and the effect on weight gain following a challenge infection, decreased with an optimum dose between 150-200 Gy. Based on this finding, broiler chicks were immunized with a mixture of E. maxima, E. acervulina, and E tenella that had been exposed to 150 or 200 Gy. This resulted in more than a 100-fold reduction in litter oocyst counts and significant protection from a challenge infection, as measured by improved weight gain and feed conversion ratio (FCR). Immunization of birds with oocysts receiving 200 Gy was less effective in providing protection from a challenge infection. An additional formulation of vaccines containing two different oocyst doses of the three species that had been irradiated with 150 Gy were evaluated in their ability to attenuate oocyst output and convey protection to challenge. Results were similar with both high and low numbers of irradiated oocysts. Immunized chicks shed less oocysts at 7 days postimmunization and were protected from negative effects of challenge infection as measured by FCR, changes in weight gain, lesion scores, and measurement of body composition. However, the level of protection was somewhat less than that achieved by immunization with nonirradiated oocysts. The overall conclusion is that an irradiated oocyst vaccine developed in this study can effectively protect chicks that are raised on litter from challenge infection with multiple species of Eimeria, comparable to vaccines with virulent or precocious strains.
    Avian Diseases 09/2014; 58(3):391-7. DOI:10.1637/10679-092613-Reg.1 · 1.11 Impact Factor
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    ABSTRACT: Abstract Previous studies comparing the genome sequences of Cryptosporidium parvum with C. hominis identified a number of highly divergent genes that might reflect positive selection for host specificity. In the present study, the C. parvum DNA sequence cgd8-5370, that encodes a protein whose amino acid sequence differs appreciably from its homologue in C. hominis, was cloned by PCR and expressed as a recombinant protein in Escherichia coli. Antisera raised against the recombinant cgd8-5370 antigen strongly recognized a unique 33 kDa protein in immunoblots from reducing and non-reducing SDS-PAGE of native C. parvum protein. However, anti-Cp33 sera did not recognize the native 33 kDa homologue in C. hominis. In an immunofluorescence assay (IFA), anti-Cp33 serum recognized an antigen in the anterior end of air-dried C. parvum sporozoites, but failed to bind at any sites in C. hominis sporozoites, indicating its specificity for C. parvum. IFA staining of live C. parvum sporozoites with anti-Cp33 serum failed to bind to the parasite, indicating that the CP33 antigen is not on the sporozoite surface, which is consistent with topology predictions based on the encoded amino acid sequence. RT-PCR analysis of cgd8-5370 mRNA before or during C. parvum oocyst excystation revealed transcripts only in excysting sporozoites. Thus, Cp33 represents one of a small number of proteins shown to differentiate C. parvum from C. hominis sporozoites and oocysts.
    Journal of Parasitology 03/2014; 100(4). DOI:10.1645/13-433.1 · 1.26 Impact Factor
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    ABSTRACT: Control of avian coccidiosis is increasingly being achieved by the administration of low doses of Eimeria oocysts to newly hatched chicks. The purpose of this study was to test the efficacy of gel beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine to protect broilers raised in contact with litter. Newly hatched chicks were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel beads. Control, 1-day-old chicks were given an equivalent number of Eimeria oocysts (10(3) total) by oral gavage or received no vaccine (nonimmunized controls). All chicks were raised in floor-pen cages in direct contact with litter. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E. acervulina, E. maxima, and E. tenella challenge infection. Chickens immunized with Eimeria oocysts in gel beads or by spray vaccination displayed significantly (P < 0.05) greater weight gain (WG) compared to nonimmunized controls. Feed conversion ratio (FCR) also showed a significant (P < 0.05) improvement in both groups relative to nonimmunized controls. Moreover, WG and FCR in both groups was not significantly different (P > 0.05) from chickens immunized by oral gavage or from nonimmunized, noninfected controls. Oocyst excretion after Eimeria challenge by all immunized groups was about 10-fold less than in nonimmunized controls. These findings indicate that immunization efficacy of gel beads and spray vaccination is improved by raising immunized chicks in contact with litter.
    Avian Diseases 09/2013; 57(3):622-6. DOI:10.1637/10516-022213-Reg.1 · 1.11 Impact Factor
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    ABSTRACT: The present study is the first characterization of Neospora caninum macrophage migration inhibitory factor (NcMIF). BLAST-N analysis of NcMIF revealed high similarity (87%) to the Toxoplasma gondii MIF. NcMIF was cloned and expressed in Escherichia coli in 3 forms, NcMIF (mature protein), NcMIFm (mutation of proline-2 to glycine), and NcMIFhis (addition of a polyhistidine tag at the N-terminus). None of these recombinant NcMIFs (rNcMIF) had tautomerase, oxidoreductase, or immunologic regulatory activities. rNcMIF was unable to compete with recombinant human MIF for a MIF receptor (CD74), suggesting that NcMIF does not bind to this MIF receptor. The glycine substitution for proline-2 of NcMIF resulted in increased retention time on SEC-HPLC and decreased formation of dimers and trimers. The addition of N-terminal HIS-tag led to increased formation of trimers. Immunofluorescence staining demonstrated that NcMIF was localized to the apical end of N. caninum tachyzoites. Immunoelectron microscopy further revealed that NcMIF was present in the micronemes, rhoptries, dense granules, and nuclei. NcMIF was abundant in the tachyzoite lysate and present in excretory and secretory antigen (ESAg) preparations. Total and secretory NcMIF was more abundant in a non-pathologic clone, Ncts-8, than in the wild type isolate (NC1). Furthermore, NcMIF release by the both isolates was increased in the presence of calcium ionophore. This differential production of NcMIF by the pathologic and non-pathologic isolates of N. caninum may suggest a critical role of this molecule in the infectious pathogenesis of this parasite.
    Experimental Parasitology 07/2013; 135(2). DOI:10.1016/j.exppara.2013.07.001 · 1.86 Impact Factor
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    ABSTRACT: A recently completed analysis of Eimeria maxima transcriptome identified a gene with homology to sequences expressed by E. tenella and E. acervulina but lacking homology with other organisms including other apicomplexans. This gene, designated Eimeria-specific protein (ESP), codes for a protein with a predicted molecular weight of 19 kDa. The ESP gene was cloned and the recombinant protein expressed in bacteria and purified for preparation of specific antisera. Quantitative RT-PCR showed transcription of ESP was low in unsporulated oocysts and after 24 h of sporulation. However, transcription nearly doubled after 48 h of sporulation and reached its highest levels in sporozoites (SZ) and merozoites (MZ). The protein was detectable by Western blot in both sporulated oocysts and in SZ and MZ. Immuno-localization by light microscopy identified ESP in paired structures in the anterior of SZ and MZ. Immuno-localization by electron microscopy identified ESP in MZ rhoptries but no specific staining of any SZ structures was detected. In addition, localization studies on intestinal sections recovered from birds 120-h post-infection indicates that oocysts do not stain with anti-ESP but staining of microgametocytes and developing oocysts was observed. The results indicate that ESP is associated with the rhoptry of E. maxima and that the protein may have functions in other developmental stages.
    Parasitology Research 07/2013; 112(10). DOI:10.1007/s00436-013-3518-9 · 2.33 Impact Factor
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    ABSTRACT: A number of parameters have been used to assess the impact ofcoccidiosis on chickens in clinical settings as well as in experimental studies. However, a rapid way to determine body composition would be useful to evaluate or compare responses to coccidia and could give further insight into the metabolic impact of infection. The current study evaluates the use of dual X-ray absorptiometry (DEXA) to determine the impact of coccidiosis on body composition in chicks receiving inoculations with single or mixed species of Eimeria. Chicks infected with Eimeria maxima, Eimeria acervulina, or Eimeria tenella had altered parameters of body composition as measured by DEXA at 6 days postinfection (PI). The greatest effects were noted in birds infected with E. acervulina or E. maxima, where lean mass and fat were reduced from control values about 75% and 85%, respectively. In chicks infected with E. tenella, tissue and fat were reduced about 10%. Bone mineral content (BMC) was about 75% of control values in birds infected with E. acervulina or E. maxima, but only E. acervulina altered bone mineral density (BMD). The decreases in BMC and BMD are likely due to malabsorption. In chicks receiving a mixed coccidian infection, all DEXA parameters were significantly decreased at 8 days PI compared with age-matched controls. As with single infections, BMD and BMC were significantly depressed (P < 0.05). Values of all DEXA parameters were near 92% of control values by day 16 PI. Analysis of all birds in the current study indicates DEXA tissue weight slightly underestimated the gravimetrically measured weight by about 3%. The current results demonstrate that DEXA is a potentially important tool for the rapid evaluation of the effect of coccidiosis on broiler chicks and suggest it can be useful for evaluation of vaccines and other disease controls.
    Avian Diseases 06/2013; 57(2):199-204. DOI:10.1637/10392-092812-Reg.1 · 1.11 Impact Factor
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    ABSTRACT: Abstract Outbreaks of avian coccidiosis may occur when susceptible chickens are raised on litter containing viable Eimeria oocysts. The purpose of this study was to compare the relative sensitivities of E. acervulina, E. maxima, and E. tenella oocysts to dessication. Sporulated E. acervulina, E. maxima, or E. tenella oocysts were incorporated into gelatin beads, and incubated at 32oC for 0, 1, 2, or 3 days. In vitro oocyst excystation rates were measured for each combination of Eimeria species and incubation time. Day-old broiler chicks were allowed to ingest the oocysts-containing beads, and total oocyst production was measured from days 5-8 post-inoculation. Although no effect on excystation was observed, E. maxima oocysts displayed greater resistance to drying compared to E. acervulina and E. tenella oocysts. Eimeria acervulina oocyst production decreased 100-fold after 1-2 days incubation. E. tenella oocysts were slightly more resistant to drying in that a 100-fold decrease in oocyst production was delayed until 2 days. For both E. acervulina and E. tenella, very few oocysts were observed after 3 days incubation. Eimeria maxima oocyst production remained high at all timepoints. Subsequent studies revealed E. maxima oocyst production was ablated only after 5 days incubation. These findings may explain in part the observed prevalence of E. maxima in litter from commercial poultry operations.
    Journal of Parasitology 04/2013; 99(5). DOI:10.1645/13-192.1 · 1.26 Impact Factor
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    ABSTRACT: Macrophage migration inhibitory factor (MIF) is a soluble factor produced by sensitized T lymphocytes that inhibits the random migration of macrophages. Homologues of MIF from invertebrates have been identified, making it an interesting molecule from a functional perspective. In the present study, the localization of a parasite MIF protein as well as its effect on the host was characterized. Western blot analysis shows that Eimeria MIF (EMIF) is found during all parasite developmental stages tested. Transmission electron microscopy shows that MIF is distributed throughout cytosol and nucleus of Eimeria acervulina merozoites. Immunohistochemical analysis suggests that EMIF may be released into the surrounding tissues as early as 24 h after infection, while later during oocyst formation, MIF expression is localized to areas immediately surrounding the oocysts, as well as in wall-forming bodies. The chemotaxis assay revealed an inhibitory function of EMIF on chicken monocyte migration. Quantitative real-time PCR was performed to examine the effect of EMIF on host immune system by measuring the transcripts of inflammatory mediators. An ex vivo stimulation study showed that E. acervulina MIF (EaMIF) enhanced expression of pro-inflammatory cytokines and chemokines in the presence of lipopolysaccharide (LPS). Furthermore, sequential treatment of adherent peripheral blood mononuclear cells with EaMIF, chicken MIF, and LPS in 2-h intervals led to the highest levels of interleukin (IL)-1B, chemokine CCLi3, IL-18, and interferon-gamma mRNA expression. This study shows that parasite MIF is widely expressed and may have potential effects on the immune system of the host.
    Parasitology Research 02/2013; 112(5). DOI:10.1007/s00436-013-3345-z · 2.33 Impact Factor
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    ABSTRACT: As a member of the interleukin (IL)-10 family, IL-22 is an important mediator in modulating tissue responses during inflammation. Through activation of STAT3-signaling cascades, IL-22 induces proliferative and anti-apoptotic pathways, as well as antimicrobial peptides (AMPs), that help prevent tissue damage and aid in its repair. This study reports the cloning and expression of recombinant chicken IL-22 (rChIL-22) and its soluble receptor, rChIL22BP, and characterization of biological effects of rChIL-22 during inflammatory responses. Similar to observations with mammalian IL-22, purified rChIL-22 had no effect on either peripheral blood mononuclear cells (PBMCs) or lymphocytes. This was due to the low expression of the receptor ChIL22RA1 chain compared to ChIL10RB chain. rChIL-22 alone did not affect chicken embryo kidney cells (CEKCs); however, co-stimulation of CEKCs with LPS and rChIL-22 enhanced the production of pro-inflammatory cytokines, chemokines and AMPs. Furthermore, rChIL-22 alone stimulated and induced acute phase reactants in chicken embryo liver cells (CELCs). These effects of rChIL-22 were abolished by pre-incubation of rChIL-22 with rChIL22BP. Together, this study indicates an important role of ChIL-22 on epithelial cells and hepatocytes during inflammation.
    Cytokine 09/2012; 60(3). DOI:10.1016/j.cyto.2012.08.005 · 2.87 Impact Factor
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    ABSTRACT: Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.
    Avian Diseases 06/2012; 56(2):306-9. DOI:10.1637/10133-994012-DIGEST.1 · 1.11 Impact Factor
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    ABSTRACT: Abstract The present study analyzed giardin transcription in trophozoites and cysts during encystation of Giardia lamblia. Encystment was induced using standard methods, and numbers of trophozoites and cysts were counted at various time-points during the process. At all time points, RNA from both stages were assayed for levels of alpha2-, beta-, and delta-giardin mRNA as well as cyst wall protein 3 (CWP3) mRNA using quantitative RT-PCR. In encystation medium, the number of G. lamblia trophozoites decreased, while the number of cysts increased between 0 and 72 hr. In trophozoites, alpha2- and beta-giardin transcription decreased over time, while delta-giardin transcription remained unchanged during the same time period. CWP3 transcription exhibited a slight increase in trophozoites at 8 hr, followed by a decrease at subsequent time points. Expression of alpha2-giardin increased at 48 hr in cysts, followed by decreased expression at 72 hr, while beta- and delta-giardin expression was unchanged during encystation. CWP3 transcription gradually decreased from 24 -72 hr in cysts. Consistent with previous studies, giardin proteins appeared to be disassembled into amorphous structures inside cysts during encystation. These findings represent the first analysis of giardin transcription in separate populations of trophozoites and cysts during encystation, and indicate differential regulation of giardin mRNA expression by these developmental stages.
    Journal of Parasitology 04/2012; 98(6). DOI:10.1645/GE-2970.1 · 1.26 Impact Factor
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    ABSTRACT: Immunolocalization of β- and δ-giardin in Giardia duodenalis trophozoites revealed that both giardins are strictly associated with the ventral disk (VD). Optical sectioning of the immunolabeled VD, together with quantitative colocalization of δ- and β-giardin immunoreactivity, demonstrated that δ-giardin is primarily localized to the ventral side, and β-giardin is localized to the dorsal side of the VD.
    Parasitology Research 02/2012; 111(1):241-8. DOI:10.1007/s00436-012-2825-x · 2.33 Impact Factor
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    ABSTRACT: Improvements in the serological diagnosis of neosporosis are needed to differentiate acute versus chronic Neospora caninum infections. In the present study, N. caninum microneme protein 10 (NcMIC10), similar to other microneme proteins, was shown to be released in a calcium-dependent manner. NcMIC10 may be discharged during active invasion of host cells by the parasite, and thus represent an excellent marker for the diagnosis of neosporosis. In order to test this hypothesis, recombinant NcMIC10 (rNcMIC10) was expressed in Escherichia coli, and polyclonal antibodies were generated against non-overlapping fragments of the protein. A capture ELISA was developed using these antibodies, and was found to be highly accurate and reproducible with a detection range of 10-10,000 pg/ml. The anti-rNcMIC10 antibodies used in this study did not cross-react with the Toxoplasma gondii antigens. NcMIC10 was detected by the ELISA in sera of 9 out of 10 goats (90%) experimentally infected with N. caninum tachyzoites. In general, goats infected with a lower dose (10(4)) of the parasite displayed a peak in NcMIC10 levels between weeks 4 and 5 post infection. Goats infected with a higher parasite dose (10(6)) displayed a more rapid increase in NcMIC10 levels. In most animals, NcMIC10 decreased to undetectable levels by week 6 post infection. This is the first circulating Neospora antigen-based assay which may complement the existing antibody-based assays for a rapid and cost-effective definitive diagnosis of neosporosis in livestock.
    Veterinary Parasitology 01/2012; 187(1-2):28-35. DOI:10.1016/j.vetpar.2012.01.003 · 2.55 Impact Factor
  • Wenbin Tuo · Yan Zhao · Daming Zhu · Mark C Jenkins
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    ABSTRACT: Neospora caninum is the causal agent of bovine neosporosis which results in high levels of abortion. The present study determined the protective efficacy of two Neospora antigens--Neospora cyclophilin (NcCyP) and NcSRS2. The ability of native NcCyP to upregulate mouse IFN-γ was also confirmed in this study. Recombinant NcCyP or NcSRS2 were tested either alone or in combination and formulated with adjuvant ImmuMax-SR and CpG. Female BALB/c mice (n=15) of 10-12 weeks of age were immunized s.c. twice over a 2-week interval with vaccines containing either NcCyP (20 μg/dose) alone, NcSRS2 (20 μg/dose) alone, NcCyP plus NcSRS2, or non-recombinant bacterial antigen (NR) in 2 separate trials. All mice were challenge-infected 3 weeks following the booster immunization and necropsied 3 weeks after the challenge infection. Brain and serum were collected and Nc-specific DNA sequence in brain tissue and antibodies in serum were analyzed by PCR or ELISA/Western blotting. Results showed that mice vaccinated with rNcCyP, rNcSRS2, or both rNcCyP and rNcSRS2 responded with high levels of NcCyP or NcSRS2 specific antibodies. Overall, mice received vaccines formulated with either rNcCyP or rNcCyP and rNcSRS2 had a higher (p<0.01) percent protection when compared to the mock- or non-vaccinated mice. The group immunized with rNcSRS2 alone exhibited slightly lower levels of protection, which was higher (p<0.05) than that of the non-vaccinated group but did not differ (p=0.06) from that of the mock-vaccinated group. The results of the present study indicate that NcCyP is a highly efficacious vaccine candidate which may be useful in protection against Neospora infection.
    Vaccine 03/2011; 29(13):2392-9. DOI:10.1016/j.vaccine.2011.01.041 · 3.49 Impact Factor
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    ABSTRACT: The present study describes transcription of mRNA from genes encoding metabolic or structural proteins during excystation of Cryptosporidium parvum oocysts. RNA was harvested from C. parvum oocysts before excystation, and at 5, 10, and 15 min during excystation. Subtractive cDNA libraries were prepared by using mRNA from non-excysted C. parvum oocysts to "subtract out" mRNA from excysting oocysts. The "subtracted" cDNA was used to prepare libraries enriched for transcripts possibly involved in excystation. From these libraries, over 1,000 expressed sequence tags (ESTs) were analyzed by DNA sequencing followed by BLAST-N and BLAST-X analysis. While several gene products involved in cell metabolism and cell signaling were consistently recovered, transcription levels, as reflected by the relative number of cDNA sequences (19.2% total), were highly up-regulated in genes coding for structural proteins such as Cp2, CpTSP, CpHC10, and CpSAg. Moreover, of the greater than 1,000 clones analyzed, a high percentage (12.3%) of ESTs detected in excysting oocysts were for hypothetical C. parvum proteins (CpHyP), whose functions are presently unknown.
    Parasitology Research 03/2011; 109(2):509-13. DOI:10.1007/s00436-011-2308-5 · 2.33 Impact Factor
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    ABSTRACT: Intestinal colonization of avian species by Eimeria parasites results in the enteric disease, coccidiosis. A study was carried out to assess the immunologic effects of Eimeria praecox infection on the gut of infected chickens. In Experiment 1, birds were orally gavaged with 50,000 E. praecox oocysts; in Experiment 2, an infection dosage of 500,000 E. praecox oocysts was used. Duodenal and jejunal intestinal sections were sampled consecutively on days 1-7 post-infection. Intestinal expression of innate immune gene transcripts was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Analysis of relative gene expression in Experiment 1 revealed an increase (P<0.05) in duodenal Toll-like receptor (TLR)3 expression on days 4 and 6 post-infection. TLR15 expression was significantly decreased in the duodenum of infected birds on day 2, and significantly increased on day 6 post-infection. In Experiment 2, TLR3 was significantly downregulated in the duodenum on day 7 post-infection; however, no significant results were observed in terms of TLR15 expression. TLR4 also exhibited decreased expression (P<0.05) on day 7 post-infection in both intestinal sections. Regarding antimicrobial peptide expression; in the first experiment, expression of liver-expressed antimicrobial peptide-2 (LEAP-2) in infected birds was significantly decreased in the duodenum on days 3 and 4, and in the jejunum on day 4. Similarly, Experiment 2 resulted in depression of LEAP-2 (P<0.05) on days 3-5 in the duodenum. In Experiment 1, cathelicidin antimicrobial peptide (CATHL3) was downregulated (P<0.05) in the jejunum of infected chickens on day 3 post-infection; however, CATHL3 results were non-significant in Experiment 2. Based on the differing results observed in each experiment, it was concluded that both TLR and antimicrobial peptide expression, and thus immunity may be dependent on infection load.
    Experimental Parasitology 03/2011; 127(3):714-8. DOI:10.1016/j.exppara.2010.12.002 · 1.86 Impact Factor
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    ABSTRACT: Macrophage migration inhibitory factor (MIF) is recognized as a soluble factor produced by sensitized T lymphocytes and inhibits the random migration of macrophages. Recent studies have revealed a more prominent role for MIF as a multi-functional cytokine mediating both innate and adaptive immune responses. This study describes the cloning and functional characterization of avian MIF in an effort to better understand its role in innate and adaptive immunity, and potential use in poultry health applications. The full-length avian MIF gene was amplified from stimulated chicken lymphocytes and cloned into a prokaryotic expression vector. The confirmed 115 amino acid sequence of avian MIF has 71% identity with human and murine MIF. The bacterially expressed avian recombinant MIF (rChMIF) was purified, followed by endotoxin removal, and then tested by chemotactic assay and quantitative real-time PCR (qRT-PCR). Diff-Quick staining revealed a substantial decrease in migration of macrophages in the presence of 0.01microg/ml rChMIF. qRT-PCR analysis revealed that the presence of rChMIF enhanced levels of IL-1beta and iNOS during PBMCs stimulation with LPS. Additionally, the Con A-stimulated lymphocytes showed enhanced interferon (IFN)-gamma and IL-2 transcripts in the presence of rChMIF. Interestingly, addition of rChMIF to the stimulated PBMCs, in the presence of lymphocytes, showed anti-inflammatory function of rChMIF. To our knowledge, this study represents the first report for the functional characterization of avian MIF, demonstrating the inhibition of macrophage migration, similar to mammalian MIF, and the mediation of inflammatory responses during antigenic stimulation.
    Developmental and comparative immunology 09/2010; 34(9):1021-32. DOI:10.1016/j.dci.2010.05.005 · 3.71 Impact Factor
  • M Jenkins · S Klopp · D Ritter · K Miska · R Fetterer
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    ABSTRACT: The purpose of the present study was to evaluate the species composition and salinomycin sensitivity of Eimeria oocysts isolated from commercial broiler farms that differed by means of coccidiosis control (anticoccidial drugs [ACD] vs. live oocyst vaccines [VAC]). A comparison of Eimeria species composition and salinomycin sensitivity was also made before and after a producer switched from salinomycin to live oocyst vaccines. In general, no significant difference was observed in the concentration of Eimeria spp. oocysts in litter from VAC-utilizing farms compared to litter from ACD-utilizing farms. Application of PCR-based methods to detect coccidia found that Eimeria species distribution in litter from VAC operations more closely resembled the species composition in the live oocyst vaccines. Drug sensitivity testing found that Eimeria oocysts from VAC operations displayed greater salinomycin sensitivity as measured by weight gain and feed conversion efficiency compared to oocysts from ACD farms. These findings provide additional evidence for the usefulness of live oocyst vaccines to restore ionophore sensitivity in poultry operations that contain an ionophore-resistant population of Eimeria spp. oocysts.
    Avian Diseases 09/2010; 54(3):1002-6. DOI:10.1637/9137-111109-Reg.1 · 1.11 Impact Factor

Publication Stats

2k Citations
201.08 Total Impact Points


  • 1996–2014
    • Agricultural Research Service
      ERV, Texas, United States
  • 1995–2011
    • United States Department of Agriculture
      • Agricultural Research Service (ARS)
      Washington, Washington, D.C., United States
  • 2007
    • The University of Calgary
      • Faculty of Veterinary Medicine
      Calgary, Alberta, Canada
  • 2004
    • Justus-Liebig-Universität Gießen
      • Institute of Animal Nutrition and Nutritional Physiology
      Gieben, Hesse, Germany
  • 1997
    • University of Guelph
      • Department of Pathobiology
      XIA, Ontario, Canada
  • 1990–1993
    • Maryland Department Of Agriculture
      Annapolis, Maryland, United States
  • 1991
    • Colorado State University
      Fort Collins, Colorado, United States
  • 1989
    • Northern Illinois University
      • Department of Biological Sciences
      Декалб, Illinois, United States