1,721,047 research outputs found
Differential inhibition of recombinant bovine GH (rbGH) activity in vitro by in vivo enhancing monoclonal antibodies
No full textWe have previously described the effects of complexing recombinant bovine growth hormone (rbGH) with the in vivo enhancing monoclonal antibodies (Mabs) OA11 and OA15 and the non-enhancing Mab OA14 on the subsequent activity of GH in different tissue culture models. We reported that all of these Mabs caused the inhibition of GH-stimulated Jak-2 tyrosine kinase phosphorylation in the GH responsive pre-adipocyte cell line 3T3-F442A. However, using the mouse myeloid cell line FDC-P1 transfected with the full length ovine GH receptor (GHR), we subsequently found that OA11 and OA14 remained inhibitory with respect to the end point measurement of GH stimulated mitogenesis but that OA15 had no inhibitory effect on GH stimulated mitogenesis in this cell line. In order to correlate longer term mitogenic effects of Mab-GH complexes with signalling events in this transfected cell line model, we now report on the effects of complexing with Mab on the subsequent GH stimulated phosphorylation of Stat5b (signal transducer and activator of transcription). In agreement with our data for the mitogenic activity of GH-Mab complexes, we found that OA11 and OA14 inhibit GH activation of Stat5b but that OA15 is not inhibitory. Further to this, the dose-response effect of both OA11 and OA14 on the GH stimulation of Stat5b in the FDC-P1-oGHR transfected cells correlates with the previously described dose-response effects for both Mabs in the context of GH stimulation of mitogenic effects. We conclude that in this oGHR transfected cell line model, Mab effects on short and long term GH signalling events are tightly correlated. The observation that neither of the in vivo enhancing Mabs - OA11 or OA15 - amplifies the response to GH in our transfected cell line model, coupled with the differential nature of Mab effects on GH activity (OA11-inhibition; OA15 - no effect) may argue for an in vivo mechanism for enhancement of GH activity
Relationship between S.aureus gene pattern and dairy herd mastitis prevalence
No full textThe importance to evaluate Staphylococcus aureus virulence analysing the combination of virulence genes is largely recognised, and the recent availability of simplified microarray tools allows performing these analyses also in the dairy field. The combined availability of herd-specific S. aureus mastitis prevalence data, isolates from these herds, and microarray technology offered the opportunity to investigate the relationship between S. aureus genetic pattern and their prevalence among dairy herds. Eleven commercial dairy herds following a S. aureus control programme were enrolled in the study, and 33 S. aureus isolates were collected from these herds. Diagnostic DNA microarrays based on the array-tube platform were used for genotyping of staphylococcal DNA. The genetic analysis of the 157-genes microarray showed as only 19 genes were present in all the isolates considered, and among them the genes coding for the leukocidin subunits (LukF, LukS and LukY), haemolysins (hla, hld and an unnamed haemolysin) and enterotoxin X. Several genes considered in the arrays were absent in all the isolates, including the ones encoding the resistance to most of the antimicrobials, except for tetracycline. In our isolates, some agr alleles were never identified (B-III, C-III, D-III, C-IV and D-IV). The comparison of epidemiological data with the genetic pattern suggests that agr type II is associated to the most diffusive isolates, being recovered from the largest number of herds and with the highest frequency. Microarray technique showed to be a useful method to assess the characteristics of virulence of S. aureus isolated in dairy herds and to investigate the relationship with the prevalence of the microorganism. These results support previous evidence that specific gene patterns could be associated to S. aureus mastitis
An enzyme-linked immunosorbent assay for the determination of bovine prolactin in plasma
No full textHighly purified pituitary bovine prolactin (bPRL) has been used in a sensitive non-competitive enzyme-linked immunosorbent assay of prolactin (PRL) concentrations in plasma. In this assay affinity purified polyclonal antibodies were immobilzed to the solid phase in order to capture the antigen, and were also biotinylated as the detector antibody. The method was found to be reproducible (3% variability between calibration curves) and has been optimized for measuring bPRL concentration in plasma samples, giving an intra-assay coefficient of variation of about 5% and an interassay coefficient of variation of about 9%. The sensitivity of the assay was found to be as low as 0.1 ng/ml of bPRL
Peptide mass mapping and N-acetyl- and N-glycolyl-neuraminic acid analysis of pituitary purified bovine follicle stimulating hormone
No full textMonoclonal antibodies can reveal immunoreactivity differences between pituitary and recombinant bovine growth hormone
No full textMonoclonal antibodies (MAbs) to pituitary bovine growth hormone (bGH) were used to assay the immunoreactivity of a recombinant form of bGH. The recombinant hormone used differed from the pituitary principally in the presence of a short amino acid sequence starting with methionine added to the N-terminal end of the molecule. Monoclonal antibody 1D2 recognized the recombinant hormone with greater affinity than the pituitary hormone, whereas MAb 5G1 bound the recombinant molecule with a lower strength than the pituitary. The other MAbs showed different behavior depending on the type of immunoassay used. Results indicate that the recombinant bGH molecule has been altered in its immunological structure, and suggest a possible interaction of the added N-terminal fragment with the three-dimensional structure of the hormone
Structure and function of bovine growth hormone : bovine growth hormone as an experimental model for studies of protein-protein interactions
No full textGrowth hormone (GH) is a polypeptide that controls the differentiation, growth and metabolism of many cell types, and is secreted from the hypophysis of all vertebrate species tested so far. Despite the overlapping evolutionary, structural, immunological and biological properties, it is well-known that GHs from distinct mammalian species have significant species-specific characteristics, The main purpose of this review is to highlight bovine GH (bGH) structural features related to its species-specific properties. Novel interest in bGH is also aroused by the advent of biotechnological methods for production of recombinant proteins. In fact recombinant bGH will have a great importance in veterinary medicine research and as a 'high tech' drug that needs to be monitored in zootechnical productions
Detection of growth hormone in porcine ovarian fluids by a species-specific enzyme immunoassay
No full textDevelopment of monoclonal antibodies for an enzyme immunoassay validated to measure growth hormone in plasma of pigs and dogs
No full textAn immuno-dominant sequential epitope recognized by mouse anti-recombinant bovine growth hormone antisera
No full textThe sequential epitopes on bovine growth hormone (bGH) recognised by five polyclonal mouse antisera have been identified by scanning with multiple pin-bound peptides. Four main epitopes were identified at residues 29-40, 101-110, 139-152 and 181-191. Of these, only epitope 139-152 is recognised by all five mouse antisera indicating that, for the mouse, this may represent an immuno-dominant region of the bGH molecule
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