Effects of Eimeria maxima infection doses on growth performance and gut health in dual-infection model of necrotic enteritis in broiler chickens.

The objective of this study was to investigate the effects of the different doses of Eimeria maxima (EM) oocysts on growth performance and intestinal health in broiler chickens challenged with a dual infection model of necrotic enteritis (NE) using EM and NetB+ Clostridium perfringens (CP). A total of 432 fourteen-d-old male Cobb 500 broiler chickens were divided into 6 groups with 6 replicates each. The six different groups were as follows: Control, non-challenged; T0+, challenged with CP at 1 × 109 colony forming unit; T5K+, T0+ + 5,000 EM oocysts; T10K+, T0+ + 10,000 EM oocysts; T20K+; T0+ + 20,000 EM oocysts; and T40K+; T0+ + 40,000 EM oocysts. The challenge groups were orally inoculated with EM strain 41A on d 14, followed by NetB+ CP strain Del-1 on 4 days post inoculation (dpi). Increasing EM oocysts decreased d 21 body weight, body weight gain, feed intake (linear and quadratic, p < 0.001), and feed efficiency (linear, p < 0.001) from 0 to 7 dpi. Increasing EM oocysts increased jejunal NE lesion score and intestinal permeability on 5, 6, and 7 dpi (linear, p < 0.05). On 7 dpi, increasing the infection doses of EM oocysts increased jejunal CP colony counts (linear, p < 0.05) and increased fecal EM oocyst output (linear and quadratic, p < 0.001). Furthermore, increasing the infection doses of EM oocysts decreased the villus height to crypt depth ratios and the goblet cell counts (linear, p < 0.05) on 6 dpi. Increasing EM oocysts downregulated the expression of MUC2, B0AT, B0,+AT, PepT1, GLUT2, AvBD3 and 9, LEAP2, and TLR4, while upregulating CLDN1, CATHL3, IL-1ß, IFN-γ, TNFSF15, TNF-α, IL-10, and Gam56 and 82 on 6 dpi (linear, p < 0.05). Additionally, increasing EM oocysts decreased Pielou's evenness and Shannon's entropy (linear, p < 0.01). In conclusion, increasing the infection doses of EM significantly aggravated the severity of NE and exerted negative impact on intestinal health from 5 to 7 dpi.

Dietary Bacillus subtilis-based direct-fed microbials alleviate LPS-induced intestinal immunological stress and improve intestinal barrier gene expression in commercial broiler chickens.

This study investigated the effects of Bacillus subtilis-based probiotics on the performance, modulation of host inflammatory responses and intestinal barrier gene expression of broilers subjected to LPS challenge. Chickens were randomly allocated to one of the 3 dietary treatment groups - control, antibiotic, or probiotic. At 14days, half of the chickens in each treatment were injected with LPS (1mg/kg body weight), and the other half injected with sterile PBS. Chickens fed probiotics weighed significantly more than controls at 15days of age, irrespective of immune challenge. LPS challenge significantly reduced weight gain at 24h post-injection, and the probiotics did not alleviate the LPS-induced reduction of weight gain. Serum α-1-AGP levels were significantly higher in LPS-injected chickens, and probiotic supplementation significantly reduced their levels. The percentages of CD4+ lymphocytes were significantly increased in probiotic groups in the absence of immunological challenge but were reduced during LPS challenge compared to controls. CD8+ lymphocytes were significantly reduced in probiotic-fed birds. The LPS-induced increase in the expression of cytokines IL8 and TNFSF15 was reduced by probiotic supplementation, and IL17F, iNOS expression was found to be significantly elevated in probiotic-fed birds subjected to LPS challenge. The reduced gene expression of tight junction proteins (JAM2, occludin and ZO1) and MUC2 induced by LPS challenge was reversed by probiotic supplementation. The results indicate that B. subtilis-based probiotics differentially regulate intestinal immune and tight junction protein mRNA expression during states of LPS-mediated immunological challenge.

In ovo vaccination using Eimeria profilin and Clostridium perfringens NetB proteins in Montanide IMS adjuvant increases protective immunity against experimentally-induced necrotic enteritis.

OBJECTIVE: The effects of vaccinating 18-day-old chicken embryos with the combination of recombinant Eimeria profilin plus Clostridium perfringens (C. perfringens) NetB proteins mixed in the Montanide IMS adjuvant on the chicken immune response to necrotic enteritis (NE) were investigated using an Eimeria maxima (E. maxima)/C. perfringens co-infection NE disease model that we previously developed. METHODS: Eighteen-day-old broiler embryos were injected with 100 µL of phosphate-buffered saline, profilin, profilin plus necrotic enteritis B-like (NetB), profilin plus NetB/Montanide adjuvant (IMS 106), and profilin plus Net-B/Montanide adjuvant (IMS 101). After post-hatch birds were challenged with our NE experimental disease model, body weights, intestinal lesions, serum antibody levels to NetB, and proinflammatory cytokine and chemokine mRNA levels in intestinal intraepithelial lymphocytes were measured. RESULTS: Chickens in ovo vaccinated with recombinant profilin plus NetB proteins/IMS106 and recombinant profilin plus NetB proteins/IMS101 showed significantly increased body weight gains and reduced gut damages compared with the profilin-only group, respectively. Greater antibody response to NetB toxin were observed in the profilin plus NetB/IMS 106, and profilin plus NetB/IMS 101 groups compared with the other three vaccine/adjuvant groups. Finally, diminished levels of transcripts encoding for proinflammatory cytokines such as lipopolysaccharide-induced tumor necrosis factor-α factor, tumor necrosis factor superfamily 15, and interleukin-8 were observed in the intestinal lymphocytes of chickens in ovo injected with profilin plus NetB toxin in combination with IMS 106, and profilin plus NetB toxin in combination with IMS 101 compared with profilin protein alone bird. CONCLUSION: These results suggest that the Montanide IMS adjuvants potentiate host immunity to experimentally-induced avian NE when administered in ovo in conjunction with the profilin and NetB proteins, and may reduce disease pathology by attenuating the expression of proinflammatory cytokines and chemokines implicated in disease pathogenesis.

Induction of protective immunity against experimental Eimeria tenella infection using serum exosomes.

Avian coccidiosis is caused by Eimeria, a unicellular, apicomplexan protist which primarily infects intestinal epithelia resulting in nutrient malabsorption and reduced growth of commercial poultry. Vaccination of chickens with exosomes isolated from antigen presenting cells containing parasite antigens (Ags) represents a promising alternative strategy to control avian coccidiosis, but is restricted in its commercial application due to limitations on production scale-up for mass immunization programs. Here, we report the biochemical and physiologic characteristics of exosomes derived from serum of Eimeria tenella-infected chickens and their feasibility for inducing protective immunity to experimental coccidiosis. Exosomes isolated from the serum of E. tenella-infected chickens contained a subset of protein Ags found in the intact parasite. Serum-derived exosomes containing these E. tenella Ags localized to the intestine and spleen following intramuscular injection into naïve chickens. In vitro ELISPOT assays revealed increased numbers of IL-2-, IL-4-, IL-6-, and IFN-γ-secreting cells in the intestine and spleen of exosome-administered chickens, compared with vehicle controls. Pre-immunization of chickens with serum exosomes from E. tenella-infected chickens increased both body weight gain and feed conversion efficiency, and reduced both fecal parasite shedding and gut lesion scores following parasite infection, compared with vehicle controls. Finally, immunization with CD80(+) serum exosomes stimulated greater numbers of cytokine-producing cells, and higher levels of protective immunity to E. tenella infection, compared with CD80(-) exosomes. These results suggest the possibility of producing an effective, parasite-free vaccine against avian coccidiosis under field conditions using serum-derived CD80(+) exosomes containing parasite Ags.

Mapping and genotypic analysis of the NK-lysin gene in chicken.

BACKGROUND: Antimicrobial peptides (AMP) are important elements of the first line of defence against pathogens in animals. NK-lysin is a cationic AMP that plays a critical role in innate immunity. The chicken NK-lysin gene has been cloned and its antimicrobial and anticancer activity has been described but its location in the chicken genome remains unknown. Here, we mapped the NK-lysin gene and examined the distribution of a functionally significant single nucleotide polymorphism (SNP) among different chicken inbred lines and heritage breeds. RESULTS: A 6000 rad radiation hybrid panel (ChickRH6) was used to map the NK-lysin gene to the distal end of chromosome 22. Two additional genes, the adipocyte enhancer-binding protein 1-like gene (AEBP1) and the DNA polymerase delta subunit 2-like (POLD2) gene, are located in the same NW_003779909 contig as NK-lysin, and were thus indirectly mapped to chromosome 22 as well. Previously, we reported a functionally significant SNP at position 271 of the NK-lysin coding sequence in two different chicken breeds. Here, we examined this SNP and found that the A allele appears to be more common than the G allele in these heritage breeds and inbred lines. CONCLUSIONS: The chicken NK-lysin gene mapped to the distal end of chromosome 22. Two additional genes, AEBP1 and POLD2, were indirectly mapped to chromosome 22 also. SNP analyses revealed that the A allele, which encodes a peptide with a higher antimicrobial activity, is more common than the G allele in our tested inbred lines and heritage breeds.

IL-17A regulates Eimeria tenella schizont maturation and migration in avian coccidiosis.

Although IL17A is associated with the immunological control of various infectious diseases, its role in host response to Eimeria infections is not well understood. In an effort to better dissect the role of IL17A in host-pathogen interactions in avian coccidiosis, a neutralizing antibody (Ab) to chicken IL17A was used to counteract IL17A bioactivity in vivo. Chickens infected with Eimeria tenella and treated intravenously with IL17A Ab, exhibited reduced intracellular schizont and merozoite development, diminished lesion score, compared with untreated controls. Immunohistological evaluation of cecal lesions in the parasitized tissues indicated reduced migration and maturation of second-generation schizonts and reduced lesions in lamina propria and submucosa. In contrast, untreated and infected chickens had epithelial cells harboring second-generation schizonts, which extend into the submucosa through muscularis mucosa disruptions, maturing into second generation merozoites. Furthermore, IL17A Ab treatment was associated with increased parameters of Th1 immunity (IL2- and IFNγ- producing cells), reduced levels of reactive oxygen species (ROS), and diminished levels of serum matrix metalloproteinase-9 (MMP-9). Finally, schizonts from untreated and infected chickens expressed S100, Wiskott-Aldrich syndrome protein family member 3 (WASF3), and heat shock protein-70 (HSP70) proteins as merozoites matured, whereas the expression of these proteins was absent in IL17A Ab-treated chickens. These results provide the first evidence that the administration of an IL17A neutralizing Ab to E. tenella-infected chickens inhibits the migration of parasitized epithelial cells, markedly reduces the production of ROS and MMP-9, and decreases cecal lesions, suggesting that IL17A might be a potential therapeutic target for coccidiosis control.

Comparison of live Eimeria vaccination with in-feed salinomycin on growth and immune status in broiler chickens.

Coccidiosis vaccines and anticoccidial drugs are commonly used to control Eimeria infection during commercial poultry production. The present study was conducted to compare the relative effectiveness of these two disease control strategies in broiler chickens in an experimental research facility. Birds were orally vaccinated with a live, attenuated vaccine (Inovocox), or were provided with in-feed salinomycin (Bio-Cox), and body weights, serum levels of nitric oxide (NO) and antibodies against Eimeria profilin and Clostridium perfringens PFO proteins, and intestinal levels of cytokine gene transcripts were measured. Vaccinated chickens had increased body weights, greater NO levels, and higher profilin and PFO antibody levels compared with salinomycin-fed birds. Transcripts for interleukin-6 (IL-6), tumor necrosis factor superfamily 15, and interferon-γ were increased, while mRNAs for IL-4 and IL-10 were decreased, in immunized chickens compared with salinomycin-treated chickens. In conclusion, vaccination against avian coccidiosis may be more effective compared with dietary salinomycin for increasing body weight and augmenting pro-inflammatory immune status during commercial poultry production.

Induction of protective immunity against Eimeria tenella, Eimeria maxima, and Eimeria acervulina infections using dendritic cell-derived exosomes.

This study describes a novel immunization strategy against avian coccidiosis using exosomes derived from Eimeria parasite antigen (Ag)-loaded dendritic cells (DCs). Chicken intestinal DCs were isolated and pulsed in vitro with a mixture of sporozoite-extracted Ags from Eimeria tenella, E. maxima, and E. acervulina, and the cell-derived exosomes were isolated. Chickens were nonimmunized or immunized intramuscularly with exosomes and subsequently noninfected or coinfected with E. tenella, E. maxima, and E. acervulina oocysts. Immune parameters compared among the nonimmunized/noninfected, nonimmunized/infected, and immunized/infected groups were the numbers of cells secreting T(h)1 cytokines, T(h)2 cytokines, interleukin-16 (IL-16), and Ag-reactive antibodies in vitro and in vivo readouts of protective immunity against Eimeria infection. Cecal tonsils, Peyer's patches, and spleens of immunized and infected chickens had increased numbers of cells secreting the IL-16 and the T(h)1 cytokines IL-2 and gamma interferon, greater Ag-stimulated proliferative responses, and higher numbers of Ag-reactive IgG- and IgA-producing cells following in vitro stimulation with the sporozoite Ags compared with the nonimmunized/noninfected and nonimmunized/infected controls. In contrast, the numbers of cells secreting the T(h)2 cytokines IL-4 and IL-10 were diminished in immunized and infected chickens compared with the nonimmunized/noninfected and the nonimmunized/infected controls. Chickens immunized with Ag-loaded exosomes and infected in vivo with Eimeria oocysts had increased body weight gains, reduced feed conversion ratios, diminished fecal oocyst shedding, lessened intestinal lesion scores, and reduced mortality compared with the nonimmunized/infected controls. These results suggest that successful field vaccination against avian coccidiosis using exosomes derived from DCs incubated with Ags isolated from Eimeria species may be possible.

Induction of protective immunity against Eimeria tenella infection using antigen-loaded dendritic cells (DC) and DC-derived exosomes.

Current methods for sustainable control of avian coccidiosis, whether by prophylactic medication or parasite vaccination, are suboptimal. In this study, we describe an alternative immunization strategy against Eimeria tenella infection using parasite antigen (Ag)-loaded dendritic cells (DCs), or their derived exosomes, in the absence of free Ag. CD45(+) intestinal DCs were isolated from E. tenella-infected chickens and loaded ex vivo with an extract of sporozoites as parasite Ag. Extracellular vesicles purified from the Ag-pulsed DCs expressed surface proteins associated with DC-derived exosomes, including major histocompatibility complex proteins (MHC I and MHC II), CD80, flotillin, and heat shock protein (HSP70). Following intramuscular immunization of chickens with Ag-pulsed DCs or Ag-pulsed DC-derived exosomes, Ag-containing cells were observed diffusely localized in the lymphoid tissue and concentrated in germinal centers of caecal tonsils, and restricted to germinal centers (GC) in the spleen. Chickens immunized with pulsed DCs or exosomes exhibited (a) higher numbers of caecal tonsil and spleen cells expressing IgG and/or IgA antibodies that were reactive with E. tenella Ag, (b) greater numbers of IL-2-, IL-16-, and IFN-γ-producing cells, and (c) higher E. tenella Ag-driven cell proliferation, compared with chickens immunized with Ag in the absence of DCs or exosomes. Chickens immunized with Ag-pulsed DCs or Ag-pulsed DC-derived exosomes and subsequently given a live E. tenella challenge infection at 10d post-immunization displayed (a) increased body weight gains, (b) decreased feed conversion ratios, (c) reduced fecal oocyst shedding, (d) diminished intestinal lesions, and (e) lower mortality, compared with animals given Ag alone. This is the first demonstration of Ag-specific protective immunity against avian coccidiosis using parasite Ag-loaded DCs or DC-derived exosomes.

The butanol fraction of Eclipta prostrata (Linn) increases the formation of brain acetylcholine and decreases oxidative stress in the brain and serum of cesarean-derived rats.

Eclipta prostrata has been used as a traditional medicinal plant to prevent dementia and to enhance memory in Asia. Its potential as a nootropic and as an antioxidant have been reported in mice. We hypothesized that Eclipta may affect the formation of neurotransmitters and the inhibition of oxidative stress. Charles River cesarean-derived rats (male, 180 ± 10 g) were fed experimental diets supplemented with 0 mg (control), 25 mg (E25), 50 mg (E50), or 100 mg (E100) of a freeze-dried butanol fraction of E prostrata per kilogram of diet for 6 weeks. The acetylcholine level was significantly increased by 9.6% and 12.1% in the brains of E50 and E100 groups, respectively, as compared with the control group that was fed standard diet alone. The acetylcholine esterase activity was significantly increased by 13.1% and 19.7% in the brains of E50 and E100 groups, respectively, compared with the control group. Monoamine oxidase-B activity was significantly decreased by 10.5% in the brains of the E100 group, and the superoxide radical level was significantly reduced by 9.4% in the serum of the E100 group compared with the control group. Superoxide dismutase activity was significantly increased by 9.6% and 11.6% in the serum of E50 and E100 groups, respectively, compared with the control group. These results clearly demonstrate the effects of E prostrata on the formation of acetylcholine in the brain and the inhibition of oxidative stress in the brain and serum of rats. These findings may have implications for preventing dementia and enhancing memory function in humans.

Adaptation of a mallard H5N2 low pathogenicity influenza virus in chickens with prior history of infection with infectious bursal disease virus.

The influenza A/Mallard/Pennsylvania/10218/1984 (H5N2) virus is unable to replicate in 3-wk-old immunocompetent specific-pathogen-free chickens when a dose of 5 x 10(6) 50% egg infectious dose/ml is used. In contrast, this mallard virus shows limited replication in 3-wk-old chickens that had been previously infected at 2 days of age with, and recovered from, the immunosuppressive agent infectious bursal disease virus (IBDV; herein referred to as IBDV chickens). This limited replication in IBDV chickens allowed for the serial passage of the mallard influenza virus in chickens. After 22 passages (P22) in IBDV chickens, the resulting chicken-adapted influenza virus replicated in both immunocompetent and IBDV chickens more efficiently than the mallard influenza virus. Analysis of the outcomes of infection and the lesions caused by the two viruses at the microscopic level in a time-point study showed that the P22 virus is more virulent than the parental mallard virus in both immunocompetent and IBDV chickens. Our studies provide evidence that a previous history of IBDV infection in chickens may render them more susceptible to avian influenza virus (AIV) infections, allowing for the potential introduction of AIVs in an otherwise resistant population.

The butanol fraction of Eclipta prostrata (Linn) effectively reduces serum lipid levels and improves antioxidant activities in CD rats.

Eclipta prostrata (Linn) has been used as a traditional medicinal plant to prevent lipidemia and atherosclerosis in Asia. However, its functional properties and the underlying mechanism of action have not been clearly defined. This study was conducted to elucidate the biological basis for hypolipidemic and antioxidant activities of E. prostrata. Charles River Sprague-Dawley CD rats (specific pathogen-free/viral antibody-free Crj/Bgi male, 180 +/- 10 g) were fed experimental diets supplemented with 0 mg (control), 25 mg (E25), 50 mg (E50), or 100 mg (E100) of a freeze-dried butanol fraction of E. prostrata per kilogram of diet for 6 weeks. Serum triacylglycerol and total cholesterol levels were significantly lower in the E50 and E100 groups by 9.8% to 19.0% and by 10.7% to 13.4%, respectively, and low-density lipoprotein-cholesterol levels were significantly reduced in the same groups by 10.3% to 13.0% compared with the untreated control group. The E50 and E100 groups also showed significantly increased high-density lipoprotein-cholesterol levels (13.0%-19.1%) compared with the control group. Atherogenic indices were decreased by 9.8% to 30.5% in all groups fed diets supplemented with E. prostrata. Furthermore, serum hydroxyl radical, lipid peroxide, and oxidized protein levels were significantly decreased in the E50 and E100 groups. These results clearly demonstrate the effects of E. prostrata on serum lipid and oxidative metabolism in rats. The health-promoting effects of E. prostrata, which were demonstrated in this study in a rat model, may have implications for atherosclerosis and hypercholesterolemia in humans.

In vitro treatment of chicken peripheral blood lymphocytes, macrophages, and tumor cells with extracts of Korean medicinal plants.

A variety of different medicinal plants have traditionally been used in Asian cultures as medicinal plants to enhance immunity and treat cancers. However, limited information exists on the underlying mechanisms responsible for these immune enhancing properties. The current investigation was conducted to examine the effects of methanol extracts of 3 Korean indigenous plants (dandelion root, mustard leaf, and safflower leaf) on various in vitro parameters of innate immunity (peripheral blood lymphocyte proliferation, nitric oxide production by macrophages, and free radical scavenging activity) and tumor cell growth. All plant extracts inhibited tumor cell growth and exerted antioxidant effects compared with vehicle controls. In addition, safflower leaf extract stimulated lymphocyte proliferation and mustard leaf induced nitric oxide production. These results demonstrate, for the first time, that traditional Korean medicinal plant extracts are effective in enhancing innate immunity and suppressing tumor cell growth.

Development and characterization of a recombinant chicken single-chain Fv antibody detecting Eimeria acervulina sporozoite antigen.

Chicken monoclonal antibody (mAb), 8C3, which is reactive with a sporozoite antigen of Eimeria acervulina, is a potential therapeutic agent against avian coccidiosis caused by Eimeria spp. However, production of large amounts of 8C3 mAb in cell culture system is labor intensive and not cost-effective. Accordingly, recombinant single chain variable fragment (ScFv) antibody was constructed by amplification of the V(H) and V(L) genes from chicken hybridoma, 8C3 and when expressed in E. coli gave 5 mg l(-1). The expressed protein showed antigen binding activity equivalent to that of the parental mAb. In addition, nucleotide sequence comparison of 8C3 gene to the germline chicken V(L) genes suggested that the gene conversion with (V)lambda pseudogenes might contribute to the diversification of V(L) genes in chickens.

Identification and characterization of chicken interleukin-16 cDNA.

Interleukin-16 is an inflammatory cytokine synthesized as a precursor protein (pro-IL-16). Based on sequence data from an EST cDNA library prepared from intestinal intraepithelial lymphocytes of Eimeria-infected chickens, we identified a cDNA that contained a full-length open reading frame of pro-IL-16. The encoded protein, predicted to consist of 607 amino acids, showed 86% sequence identity to duck pro-IL-16 and 49-52% identity to various mammalian homologues. By Northern blot analysis, IL-16 transcripts were identified in chicken lymphoid tissues but none of the non-lymphoid tissues examined. A recombinant protein containing the 149 C-terminal amino acids of pro-IL-16, expressed in COS-7 cells, showed chemoattractant activity for splenic lymphocytes.

Identification of an alternatively spliced isoform of the common cytokine receptor gamma chain in chickens.

The common cytokine receptor gamma(gamma(c)) chain is shared by at least six cytokine receptors and plays a critical role in the regulation of immune responses. In this study, we discovered that, unlike mammals, chickens possess two different gamma(c) gene transcripts, chgamma(c)-a and chgamma(c)-b. Sequence comparisons between the cDNAs and a gamma(c) genomic clone isolated by PCR revealed that chgamma(c)-b contained an in-frame 78bp insertion between Gly-222 and Val-223 of the chgamma(c)-a sequence. This insertion most likely resulted from alternative splicing such that the fifth intron was not removed from the chgamma(c)-b transcript. Furthermore, while chgamma(c)-a and chgamma(c)-b transcripts were expressed equally in the spleen, thymus, bursa, and cecal tonsils, they were differentially expressed during the time course of Con A stimulation of splenic T lymphocytes. Western blot analysis of normal spleen lymphocytes identified 45, 53, and 64 kDa immunoreactive bands whereas only 64kDa band was detected in Con A-activated splenic lymphocytes. COS-7 cells transfected with chgamma(c)-b secreted approximately 42kDa proteins. Taken together, our results document that chickens express an alternative spliced gamma(c) receptor which is larger than the conventional transcript and this novel isoform generates soluble receptors in the transfected COS-7 cells.

Isolation and characterization of chicken interleukin-17 cDNA.

Interleukin-17 (IL-17) is a proinflammatory cytokine produced by activated T cells. A 917-bp cDNA encoding the IL-17 gene was isolated from our EST cDNA library prepared from intestinal intraepithelial lymphocytes (IELs) of Eimeria-infected chickens. It contained a 507-bp open reading frame (ORF) predicted to encode a protein of 169 amino acids (aa) with a molecular mass of 18.9 kDa, a 27-residue NH(2)-terminal signal peptide, a single potential N-linked glycosylation site, and 6 cysteine residues conserved with mammalian IL-17. Chicken IL-17 (chIL-17) shared 37%-46% amino acid sequence identity to the previously described mammalian homologs and also was homologous to the ORF 13 of Herpesvirus saimiri (HVS 13). By Northern blot analysis, IL-17 transcripts were identified in a reticuloendotheliosis virus (REV)-transformed chicken lymphoblast cell line (CU205) and conconavalin A (ConA)-stimulated splenic lymphocytes but not other chicken cell lines or normal tissues. Conditioned medium from COS-7 cells transfected with ChIL-17 cDNA induced IL-6 production by chicken embryonic fibroblasts, suggesting a functional role for the cytokine in avian immunity.