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D J Caldwell

Publications and source records attributed to D J Caldwell.

At least 19 recordsLinked to original sources
PubMed2006

Influence of orally administered CpG-ODNs on the humoral response to bovine serum albumin (BSA) in chickens.

Synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODNs) have been reported to be effective mucosal adjuvants in mice when given orally. Studies on their effectiveness in chickens are currently very limited. This study investigated whether CpG-ODNs could adjuvant the immune response to BSA when given orally to a commercial line of SCWL chickens. In two experiments, performed over time, chickens were given selected concentrations of CpG-ODNs with BSA followed by 6 consecutive days of ad libitum access to drinking water containing 1.4 mg/ml BSA. Serum responses, and in some cases intestinal specific antibodies, were measured out to 33 days post-immunization. Birds receiving a single dose of CpG-ODN had consistently higher IgG, IgM, and IgA titers in the serum, dependent upon dose, and in specific areas of the intestine when compared to the non-immunized and BSA only groups. These findings suggest that a single oral CpG-ODN administration can accelerate the kinetics of antigen specific antibodies of all three isotypes in commercial-strain chickens immunized via the drinking water using common protein antigen.

Adjuvants, Immunologic↗
PubMed2005

Comparison of prophylactic or therapeutic dietary administration of capsaicin for reduction of Salmonella in broiler chickens.

In three experiments the effects of prophylactic or therapeutic dietary inclusion of capsaicin, the pungent component of peppers, were evaluated as a nonantibiotic alternative for reduction of Salmonella in broiler chickens through culture and morphologic assessment of cecal tissue. Expt. 1 evaluated the effects of 0 or 10 ppm purified capsaicin (CAP) in the starter phase (days 1-16) on chicks challenged with Salmonella Enteritidis (SE) on day of age. Therapeutic inclusion of 10 ppm purified CAP increased (P < 0.05) liver/spleen (L/S) and ceca positive results for SE. In Expt. 2, capsaicin oleoresin (CO) was included in the finisher diet (days 30-37) at 0, 5, or 20 ppm with SE challenge on day 31. Inclusion of 5 ppm CO increased ceca positive results for SE, and a linear decrease in cecal lamina propria thickness of SE-challenged birds was observed with increased CO concentration in the diet. Expt. 3 evaluated prophylactic CO treatment at 0, 5, or 20 ppm in starter, grower, and finisher diets for resistance to SE or Salmonella Typhimurium (ST) challenge on day 14 or 29. With challenge on day 14, 5 and 20 ppm prophylactic CO feeding reduced ceca SE positive results by 37% and 26%, respectively, and ST culture rate was reduced similarly with 5 ppm CO. Lamina propria thickness of the ceca increased with 5 ppm CO feeding in SE-challenged birds, whereas a decrease was observed in nonchallenged birds fed 5 ppm CO. Challenge on day 29 of birds fed 20 ppm CO resulted in reduced L/S positive results for SE. Lamina propria thickness decreased with 5 ppm CO and SE or ST challenge compared with nonchallenged birds fed 5 ppm. An increase was observed in ST- or SE-challenged birds fed 20 ppm CO compared with nonchallenged birds fed 20 ppm CO. No differences were observed in mast cell number in either Expt. 2 or 3. These data provide evidence that prophylactic or therapeutic dietary capsaisin differentially affects broiler susceptibility to Salmonella.

Animal Feed↗
PubMed2004

Intestinal mucosal mast cell immune response and pathogenesis of two Eimeria acervulina isolates in broiler chickens.

Four experiments were conducted comparing intestinal immune responses to 2 isolates of Eimeria acervulina (EA), EA1 and EA2. In experiments 1 and 2, broiler chicks of 2 commercial breeds were divided into control (nonchallenged), EA1-, or EA2-challenged groups. On d 6 postchallenge (PC), changes in BW were determined, intestinal lesions were scored, and duodenal tissue was evaluated for morphometric alterations and mucosal mast cell numbers. EA1 produced classical duodenal lesions and reduced villus height to crypt depth ratios compared with controls; however, no differences were found in mast cell counts. EA2 produced different results, and observed data were suggestive of an anaphylactic-like intestinal secretory response compared with EA1 or controls. In experiment 3, tissues were analyzed from d 2 through 6 PC. Villus atrophy and crypt hyperplasia were increased on d 5 PC in both challenged groups. Mast cell counts were significantly greater on d 3 and 4 PC in EA1-challenged birds. In experiment 4, EA2 oocysts were cleaned with 5.25% sodium hypochlorite to evaluate the possibility of a bacterial contaminant contributing to the pathogenesis of intestinal alterations. No evidence of a bacterial contaminant contributing to the pathology was observed. These data are indicative of differential host response and immunovariability between different isolates of the same Eimeria species in 2 breeds of commercial broiler chickens.

Animals↗
PubMed2004

Modulation of in vitro DNA synthesis in the chicken ovarian granulosa cell follicular hierarchy by follicle-stimulating hormone and luteinizing hormone.

Folliculogenesis in domestic hens appears to be controlled by numerous factors, particularly the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The involvement of LH in follicular steroidogenesis has been described in some detail; however, the specific role of FSH has remained elusive. In 3 experiments, the effects of ovine (o)- or chicken (c)-derived FSH (oFSH, cFSH) or LH (oLH, cLH) were evaluated on in vitro DNA synthesis [3H-thymidine (3H-TdR) incorporation], indicative of cellular proliferation, of granulosa cells from F1, F3, or F5-6 preovulatory follicles. In experiment 1, oFSH or cFSH stimulated (P < 0.05) and oLH or cLH decreased DNA synthesis by F1 granulosa cells. In experiment 2, oFSH resulted in concentration-related changes in DNA synthesis by F5-6 granulosa cells; however, no significant changes were observed in F1 or F3 granulosa cells. No effect of oLH was observed on granulosa cell proliferation from any of the follicles. Similar to oFSH, cFSH resulted in concentration-related increases in DNA synthesis in granulosa cells from F5-6 follicles with smaller magnitude changes in proliferation of F1 or F3 granulosa cells. Granulosa cells from F5-6 or F3 follicles had small increases in DNA synthesis in response to cLH. These data support the proposed role for FSH in granulosa cell proliferation, possibly contributing to follicle growth, and suggest that in vitro 3H-TdR incorporation by granulosa cells may provide a sensitive and selective bioassay for chicken gonadotropin preparations. Furthermore, data suggest that proliferative responsiveness of granulosa cells to FSH or LH may differ depending on position of follicles in the preovulatory hierarchy.

Animals↗
PubMed2004

Participation of the intestinal epithelium and mast cells in local mucosal immune responses in commercial poultry.

The intestinal mucosa of commercial poultry is continually subjected to invasion or colonization by a wide array of potentially hostile enteric pathogens. Although, recent investigations have focused on lymphocyte involvement in immune responses in the intestine, lymphocyte-mediated immunity alone will not explain the barrier nature of mucosal membranes associated with rejection of many enteric pathogens upon secondary homologous challenge. Our laboratories have focused on nontraditional elements of mucosal immunity in poultry to better understand host-pathogen interactions in the intestine. Following classical and novel immunization procedures, we have identified an antigen-specific mechanism of immediate responsiveness of the mucosal epithelium characterized by epithelial chloride secretion. This mechanism, characteristic of intestinal anaphylaxis, is mediated by local immune elements. Similar mechanisms in mammals contribute to the barrier nature of mucosal membranes during pathogen challenge. To identify cells participating in these and similar responses, additional studies have described a role for mast cells in acute phase responses in the intestines of chickens experimentally challenged with Eimeria. To a more practical end, other experiments in our laboratories have characterized drinking water administration of BSA for elicitation of local and systemic antibody responses. These experiments have shown ad libitum drinking water administration of BSA to be as effective as i.p. administration of BSA; they present a novel approach to immunization of commercial poultry with protein vaccines. These investigations support continued research on host-pathogen interactions within the intestine of commercial poultry to better understand and control enteric pathogens through vaccination or immunomodulation.

Anaphylaxis↗
PubMed2004

Immunogenicity of ad libitum drinking water administration of bovine serum albumin in Leghorn chickens.

Oral administration of protein antigen in solution routinely leads to development of oral tolerance in most mammals but has been reported to be fully immunogenic in chickens. Previous studies, including several performed by our laboratory, have demonstrated that oral administration of discrete amounts of BSA for 6 consecutive days is fully immunogenic. This study was performed to determine immunoresponsiveness to protein antigen administered ad libitum at low levels in drinking water compared with i.p. and oral gavage routes of administration. Seven days following the last oral immunization, serum was assayed for IgG, bile for IgA, and tissue culture supernatant from 3 distinct lower intestinal regions for IgG and IgA in immunized and nonimmunized single-comb White Leghorn chickens. Systemic responses in the serum of experimental birds revealed a greater (P < 0.001) IgG response when BSA was administered via i.p. injection or by drinking water compared with gavage administration or nonimmunized controls. Responses measured in bile revealed that BSA administration in the drinking water resulted in a greater (P < 0.001) secretory IgA response compared with i.p. or gavage administration, and negative control groups. Intestinal antigen specific IgG, but not IgA, was elevated (P < 0.05) in all intestinal areas tested in birds immunized against BSA by drinking water and i.p. routes of administration, compared with other experimental groups. Taken together, the present experiments demonstrate that ad libitum drinking water administration of a protein antigen is as effective as i.p. administration or gavage routes of antigen exposure and potentially describe a novel approach to immunization of commercial poultry with purified protein antigens.

Administration, Oral↗
PubMed2003

Effect of bursal anti-steroidogenic peptide and immunoglobulin G on neonatal chicken B-lymphocyte proliferation.

In attempts to identify antibodies for Bursal Anti-Steroidogenic Peptide (BASP), rabbit serum was observed to reduce phorbol ester-stimulated chicken B-lymphocyte proliferation comparable to BASP. These experiments investigated the effects of IgG on B-lymphocyte proliferation. In Experiment 1, 3% rabbit serum decreased B-lymphocyte proliferation. In Experiment 2, 2 mg/ml of intact rabbit IgG or 0.65 mg/ml of IgG papain digest products, Fab and Fc, decreased B-lymphocyte proliferation. The combination of BASP and either Fab or Fc was observed to have at least an additive anti-proliferative effect. In Experiment 3, 0.01 mg/ml of either rabbit or chicken IgG, or 1.0 mg/ml of rabbit or 0.01 mg/ml of chicken Fab, Fc, and the pepsin digestion product F(ab')(2) was observed to have an anti-proliferative effect. No combined effects of BASP and IgG or IgG digest products were observed for this experiment. In Experiment 4, 12 mg/ml of chicken egg yolk IgG or 1.2 mg/ml Fab was found to suppress B-lymphocyte proliferation. Additionally, an additive effect of 12 mg/ml of IgG with BASP was again observed. The present studies suggest that IgG and its digestion products reduce phorbol-stimulated B-lymphocyte proliferation in vitro and combined treatment with IgG and BASP may have at least an additive anti-proliferative effect on B-lymphocyte proliferation.

Animals↗
PubMed2002

Fluorescent marker for the detection of crop and upper gastrointestinal leakage in poultry processing plants.

Previous published research has identified the crop as a source of Salmonella and Campylobacter contamination for broiler carcasses and reported that broiler crops are 86 times more likely to rupture than ceca during commercial processing. Presently, we evaluated leakage of crop and upper gastrointestinal contents from broilers using a fluorescent marker at commercial processing plants. Broilers were orally gavaged with a fluorescent marker paste (corn meal-fluorescein dye-agar) within 30 min of live hang. Carcasses were collected at several points during processing and were examined for upper gastrointestinal leakage using long-wavelength black light. This survey indicated that 67% of the total broiler carcasses were positive for the marker at the rehang station following head and shank removal. Crops were mechanically removed from 61% of the carcasses prior to the cropper, and visual online examination indicated leakage of crop contents following crop removal by the pack puller. Examination of the carcasses prior to the cropper detected the marker in the following regions: neck (50.5% positive), thoracic inlet (69.7% positive), thoracic cavity (35.4% positive), and abdominal cavity (34.3% positive). Immediately prior to chill immersion, 53.2% of the carcasses contained some degree of visually identifiable marker contamination, as follows: neck (41.5% positive), thoracic inlet (45.2% positive), thoracic cavity (26.2% positive), and abdominal cavity (30.2% positive). These results suggest that this fluorescent marker technique may serve as a useful tool for rapid identification of potential changes, which could reduce the incidence of crop rupture and contamination of carcasses at processing.

Animals↗
PubMed2002

In situ detection and quantification of bursa of fabricius cellular proliferation or apoptosis in normal or steroid-treated neonatal chicks.

Apoptosis, or programmed cell death, is believed to be the mechanism for depletion of lymphocytes recognizing self-antigens following clonal expansion in the bursa of Fabricius. Although bursal apoptosis has previously been shown to increase following in vivo exposure to glucocorticoids, the microanatomical site of induced or normal apoptosis has not been unequivocally established. Presently, we adapted the existing terminal deoxynucleotidal transferase-mediated dUTP nick-end labeling (TUNEL) assay for use with neonatal bursae. Similar to previous reports, TUNEL revealed that normal apoptosis is preferentially, but not exclusively, ongoing in bursal follicular cortical cells. Administration of a single dose of a synthetic glucocorticoid (dexamethasone) or androgen (19-nortestosterone) did not significantly (P < 0.05) alter follicular lymphocyte numbers or apoptosis per unit of area at the time points evaluated post-administration (6 or 24 h). However, administration of 19-Nortestosterone increased the interfollicular epithelial thickness, a change usually associated with edema, within 6 h following treatment. Additionally, administration of the androgen 19-nortestosterone significantly decreased the number of proliferating cells as detected using mouse anti-proliferating cell nuclear antigen (PCNA) as a primary immunohistochemical antibody. In normal (control) bursal sections, occasional follicles consisting of predominantly apoptotic cells were observed (0.26% of follicles). Such follicles were consistently one-tenth the area of normal follicles. This incidental finding may suggest occasional occurrence of a common signal for deletion, such as a common integral or clonal mistake, viral infection, or an aberrant paracrine signal.

Animals↗
PubMed2001

Intestinal anaphylaxis in chickens: epithelial ion secretion as a determinant and potential component of functional immunity.

Immunity to secondary protozoan infections in chickens is accompanied by rapid onset of intestinal permeability to serum proteins, an event in mammals associated with local anaphylaxis. The permeability changes in the chicken intestine are hypothesized to be mediated by mast cell-derived paracrine factors. In a test of this hypothesis, we demonstrated, using an electrophysiological correlate of intestinal anaphylaxis (antigen-induced Cl(-) secretion), that the response of the chicken intestine to antigenic stimulation is consistent with type I hypersensitivity reactions. Day-old, single-comb-white-Leghorn chickens were sensitized to bovine serum albumin (BSA). At 3 weeks of age ileal segments were mounted in Ussing-type chambers. Serosal challenge with BSA elevated the transmural short circuit current (DeltaIsc) within 1min and was maximally expressed (DeltaIsc=50-60microA/cm(2)) within 2-3 min. The magnitude of the DeltaIsc was directly related to the concentration of antigen (10-200 microg antigen/ml), was only expressed in immunized chickens, and was blocked by the mucosal application of a Cl(-) channel blocker. Data obtained in the present investigation identify epithelial ion secretion as a potential mechanism of functional immunity in the mucosal immune system of the chicken small intestine.

Anaphylaxis↗
PubMed2001

Effect of lactic acid administration in the drinking water during preslaughter feed withdrawal on Salmonella and Campylobacter contamination of broilers.

The crop is a known source of Salmonella and Campylobacter contamination. We evaluated the use of selected organic acids (0.5% acetic, lactic, or formic) in drinking water during a simulated 8-h pretransport feed withdrawal (FW). Salmonella typhimurium was recovered from 53/100 control crops and from 45/100 of crops from acetic acid-treated broilers. However, treatment with lactic acid (31/100) or formic acid (28/76) caused significant (P < 0.05) reduction in incidence. Reductions of recovered incidence were also associated with reduced numbers of S. typhimurium recovered (e.g., control, log 1.45 cfu/crop; lactic acid, 0.79 cfu/crop). In an additional commercial farm study, broilers were provided 0.44% lactic acid during a 10-h FW (4 h on the farm and 6 h transport) and pre-FW crop, post-FW crop, and pre-chill carcass wash samples were collected for Campylobacter and Salmonella detection. Crop contamination with Salmonella was significantly reduced by lactic acid treatment (6/175) as compared with controls (29/175). Importantly, Salmonella isolation incidence in prechill carcass rinses was significantly reduced by 52.4% with the use of lactic acid (26/175 vs. 55/176). Crop contamination with Campylobacter was significantly reduced by lactic acid treatment (62.3%) as compared with the controls (85.1%). Lactic acid also reduced the incidence of Campylobacter found on pre-chill carcass rinses by 14.7% compared with the controls. These studies suggest that incorporation of lactic acid in the drinking water during pretransport FW may reduce Salmonella and Campylobacter contamination of crops and broiler carcasses at processing.

Animals↗
PubMed2000

Antimicrobial residue detection in chicken yolk samples following administration to egg-producing chickens and effects of residue detection on competitive exclusion culture (PREEMPT) establishment.

Competitive exclusion (CE) cultures may offer alternatives to antimicrobial agents for disease prophylaxis in poultry. To avoid potential transfer of antibiotic resistance, safe and effective CE cultures must, by necessity, be highly sensitive to antimicrobial residues. The following studies evaluated the effect of maternal administration of selected antibiotics on the establishment of a licensed CE culture, PREEMPT. Selected antibiotics were administered to actively laying hens for a period of 7 days (experiment 1) or 9 days (experiment 2) in drinking water [sulfadimethoxine (0.05%), enrofloxacin (0.005%), and tylosin tartrate (0.05%)] or feed (sulfadimethoxine with ormetoprim, 250 ppm). In experiment 1, fertile eggs were collected daily and subjected to bioassay for detectable antimicrobial residues in yolk. Antimicrobial residues were not detected during the 7 days of treatment or the subsequent 3 days following cessation of treatment in the control, sulfadimethoxine, sulfadimethoxine with ormetoprim, or tylosin treatment groups. However, detectable residues were observed in eggs derived from enrofloxacin-treated hens on days 6 and 7 during antibiotic administration and also on days 2 and 3 post-antibiotic administration. In experiment 2, antimicrobial residues were also only detected in yolks from hens treated with enrofloxacin. Residue detection occurred on days 2-6 of antibiotic administration, on day 9 of antibiotic administration, on days 1-3 post-antibiotic administration, and also on day 7 post-antibiotic administration. A subset of eggs from each experimental group, corresponding to days 2-6 of antibiotic administration, days 4-6 post-antibiotic administration, and days 14-16 post-antibiotic administration, were pooled for incubation, and chicks hatched from these pools of fertile eggs were treated with PREEMPT at hatch. When 48-h cecal propionate concentrations were used as an index of culture establishment, reduced (P < 0.05) efficacy was observed only in chicks derived from enrofloxacin-treated hens at either collection period. Although several antibiotics do not appear to produce detectable egg residues or interfere with CE culture establishment, these data suggest that chicks derived from enrofloxacin-treated hens may not be candidates for safe and effective CE culture treatment.

Animals↗
PubMed2000

Development of a rapid and inexpensive assay for the nonspecific detection of antimicrobial residues in chicken egg yolks and neonatal yolk sacs.

Competitive exclusion of intestinal pathogens by administration of beneficial and defined cultures of normal intestinal microflora is a safe and effective means of reducing the incidence and severity of chick infections with Salmonella and other intestinal pathogens. It is important that competitive exclusion cultures not carry genetic material (e.g., plasmids), which could transfer antibiotic resistance to other microflora, including pathogens. As such, safe and effective competitive exclusion cultures must be sensitive to commonly used antimicrobial agents. By necessity, intentional or accidental exposure of these beneficial microflora to antibiotics will reduce or eliminate the protection provided by competitive exclusion culture establishment. As antibiotic residues can be present from embryonic, hatchling, or maternal administration, a rapid and sensitive assay for the nonspecific detection of residues, which could interfere with competitive exclusion culture establishment, is needed. This study was conducted to develop a rapid and inexpensive bioassay to detect multiple antimicrobial residues in egg yolk and neonatal yolk sacs. Aerobic bacterial strains with known sensitivity to several antibiotics used by the poultry industry were selected and individually compared for sensitivity to enrofloxacin, gentamicin, tetracycline, ceftiofur, and tylosin concentrations in egg yolks. This assay was found to be relatively sensitive for the detection of these antimicrobials, and detection of residues was associated with reduced competitive exclusion culture (PREEMPT) establishment in one experiment. Importantly, this assay can be implemented with minimal training or equipment under commercial hatchery practices and could be used to determine embryo groups, in advance of hatch, that are not suitable candidates for competitive exclusion treatment in the hatchery.

Animals↗
PubMed2000

The effect of in ovo or day-of-hatch subcutaneous antibiotic administration on competitive exclusion culture (PREEMPT) establishment in neonatal chickens.

The effect of in ovo or day-of-hatch subcutaneous antibiotic administration on the detection of antibiotic residues in yolk sac or blood serum samples and the potential for observed residues to interfere with competitive exclusion (CE) culture establishment was compared in three experiments. The in ovo or subcutaneous administration of gentamicin sulfate or ceftiofur sodium was associated with detectable levels of antibiotic residues in yolk sac or blood serum samples in Experiment 1. Further, the ability to detect antibiotic residues in day-of-hatch chicks was associated with reduced levels of CE culture establishment when cecal propionate level, an indicator of PREEMPT establishment, was determined following PREEMPT application by oral gavage on the day of hatch in Experiments 1 and 2. Restricting chicks from feed, as opposed to providing access ad libitum to a starter ration, for 6 h immediately following administration of PREEMPT improved (P < 0.05) CE culture establishment in Experiment 2 in nonantibiotic injected control chicks, but did not affect (P > 0.05) experimental groups receiving either gentamicin sulfate or ceftiofur sodium by either in ovo or subcutaneous routes. The in ovo administration of 0.1 or 0.2 mg ceftiofur sodium to individual embryos on Day 18 of embryogenesis in Experiment 3 was associated with marked depressions (P < 0.05) in cecal propionate levels compared with uninjected control chicks. When feed was restricted and the time of PREEMPT administration was delayed for 48 or 72 h posthatch, mean cecal propionate levels in in ovo ceftiofur sodium-injected chicks were not significantly different (P > 0.05) from controls, indicating a time- and feed restriction-associated effect on improving CE culture establishment.

Animal Feed↗
PubMed1999

Review of mononuclear cell leukemia in F-344 rat bioassays and its significance to human cancer risk: A case study using alkyl phthalates.

Elevated incidences of mononuclear cell leukemia (MNCL) have been observed in a number of chronic bioassays in the F-344 rat. As this tumor type is unique to the rat and is only common in the F-344 strain, its significance for human cancer risk is unclear. For this reason, a survey of the published literature was undertaken to assess the occurrence and etiology of MNCL in F-344 rats and to evaluate its potential significance to humans using alkyl phthalate data as an example. It was found that MNCL occurs in untreated, aged F-344 rats at a high and variable rate, it is uncommon in most other rat strains, and its background incidence has increased significantly over time. This complicates retrospective data interpretation. MNCL has not been found in other mammalian species and no histologically comparable tumor is found in humans. In general, a statistically significant increase in frequency of a common tumor in the F-344 rat is an insufficient basis for determining that a chemical presents a carcinogenic hazard to humans, particularly when that tumor is not observed in other species. As one example, the alkyl phthalates constitute one group of substances which has been associated with increased MNCL frequency in the F-344 rat after high dietary doses. In evaluating the significance of this increase in MNCL, an extensive toxicological database for phthalates indicates that toxicological effects occur only at relatively high doses, and tumor development (including MNCL) occurs only after an apparent threshold is exceeded. Phthalates are not genotoxic as a class, further supporting the hypothesis of the existence of a threshold. When these considerations are collectively evaluated, it can be concluded that a finding of increased MNCL in F-344 rats exposed for a lifetime to a nongenotoxic chemical is not toxicologically relevant to humans, even when MNCL is observed at an increased incidence that is statistically significant. Thus, the increased incidence of MNCL observed in F-344 rats exposed to some alkyl phthalates is likely a strain-specific effect of little or no relevance for humans, and characterization of these chemicals as carcinogens based on increased MNCL in F-344 rats is not scientifically supported.

Animals↗
PubMed1999

Effect of bursal antisteroidogenic peptide (BASP) on chicken embryonic pituitary secretion of growth hormone (GH) and prolactin (PRL): evaluation in a reverse hemolytic plaque assay (RHPA).

Using the reverse hemolytic plaque assay described in the present investigation, a secretagogue activity of bursal antisteroidogenic peptide (BASP) for growth hormone (GH) or prolactin (PRL) secretion was observed in chicken Day 20e pituitary cell monolayers. Partially purified BASP (ppBASP), at all concentrations evaluated (0.25 BEQ/ml, 0.75 BEQ/ml, or 1.5 BEQ/ml), induced PRL secretion by isolated lactotrophs above (P < 0.05) basal levels during the 2- and 6-hr incubation. At the 18-hr time point, neither ppBASP nor vasoactive intestinal polypeptide (VIP) was efficacious (P < 0.05) in causing an elevation in PRL-secreting cells above basal levels. ppBASP, at all concentrations evaluated (0.25 BEQ/ml, 0.75 BEQ/ml, or 1.5 BEQ/ml), caused an increase in the percentage of GH-secreting cells above (P < 0.05) basal levels during the 18-hr incubation. When evaluating the 2-hr time point alone, ppBASP, at 0.75 or 1.5 BEQ/ml, significantly (P < 0.05) elevated the percentage of GH-secreting cells to above basal levels. After the 6-hr incubation, ppBASP at 0.25 or 0.75 BEQ/ml, was efficacious in causing elevated (P < 0.05) GH secretion above basal levels. The present study indicates a secretagogue activity of BASP on PRL or GH secretion by chicken embryonic anterior pituitary cells in vitro.

Animals↗
PubMed1999

Bursal anti-steroidogenic peptide (BASP): modulation of mitogen-stimulated bursal-lymphocyte DNA synthesis.

The present study examined the effects of bursal anti-steroidogenic peptide (BASP) on mitogen-induced DNA synthesis in bursa-derived B-lymphocytes in short-term culture. Partially purified extracts of chicken bursa of Fabricius tissue, containing BASP, significantly (P < 0.05) reduced DNA synthesis in bursal-lymphocytes exposed to increasing concentrations of phorbol 12,13-dibutyrate (PDB). Following these initial observations, BASP, further purified from bursal extracts using sequential rpHPLC fractionation, was observed to reduce (P < 0.05) both B-lymphocyte PDB-stimulated DNA synthesis and ovarian granulosa cell progesterone biosynthesis with bioactivity observed at similar retention times in each assay, suggesting that each bioactivity may be due to the same or similar molecules. A similar BASP-enriched fraction was not effective in altering basal levels of DNA synthesis in chick embryonic kidney cells. Subsequently, BASP was further purified by several sequential chromatographic methods including: C-18 rpHPLC (preparative rpHPLC followed by a semi-preparative rpHPLC column), cation exchange chromatography, molecular sieve HPLC chromatography, and SDS-PAGE. Biologically active material was observed at approximately 29 or 34 kDa. Protein concentration was determined and bioactivity was evaluated. Anti-proliferative effects of this partially purified BASP on bursal-lymphocytes was observed at concentrations as low as 1.6 micrograms ml-1, with complete suppression of mitogen-stimulated DNA synthesis observed at approximately 25 micrograms ml-1. This partially purified BASP was also efficacious for attenuation of ovarian granulosa cell progesterone biosynthesis at concentrations as low as 0.4 microgram ml-1, with complete suppression of gonadotrophin-stimulated progesterone biosynthesis observed at approximately 0.8 microgram ml-1. While BASP is efficacious for attenuation of both granulosa cell steroidogenesis and bursal-lymphocyte proliferation, these data suggest that BASP is much more potent with regard to anti-steroidogenic activity.

B-Lymphocytes↗