Search Results

You are looking at 1 - 10 of 23 items for :

  • "synthetic peptides" x
  • Refine by Access: All Content x
Clear All

demonstrate that immunizing hens with synthetic peptides based on these epitopes would yield high-titered, neutralizing egg yolk antibodies for potential application in foals. Immunization with synthetic peptides offers advantages over whole virus or subunit

Open access
in American Journal of Veterinary Research

ewingii was sequenced and, consistent with OMPs of other Ehrlichia spp, was found to contain multiple OMP paralogs (n = 19). Synthetic peptides were made to reproduce predicted antigenic regions of extracellular loops for each of the 19 paralogs to

Full access
in American Journal of Veterinary Research

dogs naturally infected with TBPs should be interpreted with caution because coinfection with more than 1 TBP genera is not uncommon. To minimize cross-reactivity within and across Anaplasma and Ehrlichia genera, ELISAs that use synthetic peptides

Full access
in American Journal of Veterinary Research

LPS-neutralizing activity. 39 These activities are governed by short regions within the amino-terminus, including regions corresponding to amino acids 65 to 99 and 142 to 169. 40,41 Synthetic peptides corresponding to sequences within these regions

Full access
in American Journal of Veterinary Research

Abstract

Objective—To design short and potent analogs of bovine lactoferricin by use of the concepts of lipophilic bulk and cationic charge.

Sample Population—5 synthetic peptides of bovine lactoferricin.

Procedure—Antibacterial peptides were constructed by synthesizing several decapeptides rich in arginine and tryptophan. Basic residues of bovine lactoferricin (bLf 20-29; residues 20 to 29) were modified by substitution with arginine or lysine and nonbasic residues were modified by substitution with tryptophan, phenylalanine, or isoleucine. Synthetic peptides of bovine lactoferrin (LFB) were designated as LFB-RW (RRWWWRWRRW), LFB-KW (KKWWWKWKKW), LFB-RWa (RRWWRRWRRW), LFB-RF (RRFFFRFRRF), and LFB-RI (RRIIIRWRRI), where R, K, W, F, and I stand for arginine, lysine, tryptophan, phenylalanine, and isoleucine, respectively. Peptides were evaluated by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Staphylococcus aureus,and Enterococcus faecalis.

Results—LFB-RW, LFB-KW, and LFB-RWa possessed equivalent potency as bLf 20-29 against E coli. LFB-RW and LFB-RWa had a 2-fold increase in growth-inhibitory and bactericidal activity against S aureus, compared with bLf 20-29. LFB-RI had the lowest MIC value against E coli among the peptides but lost bactericidal activity. LFB-RW and LFB-KW had stronger bactericidal activities against S aureus or E faecalis, respectively, as well as E coli than the other synthetic peptides. LFB-RF also had antibacterial activity, but this was 2-fold less than that of LFBRW, as determined by MIC and MBC values.

Conclusions and Clinical Relevance—In construction of potent antibacterial peptides, inclusion of arginine, lysine, tryptophan, or isoleucine residues enhances effectiveness against certain bacteria, as measured by MIC or MBC values. (Am J Vet Res 2003;64:1088–1092)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the full-length complementary DNA (cDNA) sequence of equine erythropoietin (EPO) and to develop region-specific antibodies to differentiate equine EPO (eEPO) and human EPO (hEPO).

Sample Population—RNA and lysate extracted from renal tissues of an adult Thoroughbred.

Procedure—Full-length cDNA was determined by use of a reverse transcriptase-polymerase chain reaction assay and a rapid amplification of cDNA ends method. The deduced amino acid sequence was compared with sequences of EPO reported for other species. Furthermore, 4 synthetic peptides were designed in 2 distinctive parts of the eEPO and hEPO amino acid sequences to obtain antibodies specific for eEPO and hEPO. Specificity of the antibodies was tested against supernatant of homogenized equine kidney and recombinant hEPO (rhEPO) by use of western immunoblotting techniques.

Results—Analysis of the 1,181 bp in the nucleotide sequence revealed that eEPO was a residue of 192 amino acids. Similarity of eEPO with amino acid sequences of EPO from other species was 81.0% to 90.6%. Antibodies were specifically recognized by eEPO or rhEPO molecules. Anti-hEPO (161 to 165) antibody specifically recognized rhEPO. In contrast, anti-eEPO (133 to 144) antibody reacted with the equine kidney lysate.

Conclusions and Clinical Relevance—We determined the cDNA and amino acid sequence of eEPO and developed region-specific antibodies that specifically recognized eEPO or rhEPO. These antibodies may be useful in distinguishing rhEPO from eEPO in a test to detect the misuse of rhEPO in racehorses. ( Am J Vet Res2004;65:15–19)

Full access
in American Journal of Veterinary Research

Summary

The binding of bovine complement S protein (vitronectin) to Streptococcus dysgalactiae isolates from cattle with mastitis and the S protein's role in streptococcal adherence to bovine epithelial cells were investigated. All 25 clinical isolates of S dysgalactiae interacted with bovine S protein. None of the other streptococcal species tested bound to bovine S protein. The S protein-binding sites were saturable and highly sensitive to trypsin. The binding of bovine S protein to S dysgalactiae isolates was specific and could not be inhibited by other plasma proteins, such as fibronectin, albumin, fibrinogen, α2-macroglobulin, or IgG. Similarly, streptococcal binding of bovine S protein was not influenced by the synthetic peptide Gly-Arg-Gly-Asp-Ser, which constituted the host cell attachment sequence of S protein. In adherence experiments, prior binding of bovine S protein to S dysgalactiae enhanced streptococcal adherence to bovine epithelial cells. The enhancing effects by bovine S protein were abolished when the respective binding sites on the streptococci were digested by trypsin. Thus, bovine S protein could be an important mediator of adherence of S dysgalactiae to bovine epithelial cells.

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To determine whether synthetic peptides containing the arginine-glycine-aspartate (RGD) sequence inhibit equine platelet function.

Animals

For in vitro studies of blood, 3 healthy Thoroughbreds; for in vivo and ex vivo studies of administration of RGD-containing peptides, 4 young adult pony mares.

Procedure

Blood was incubated with and without addition of aspirin or RGD-containing peptides (RGDS, RPR 110885) and platelet aggregation responses and platelet adhesion to subendothelial collagen were determined. RPR 110885 was administered IV, and platelet function was evaluated. Platelet aggregation was determined by a turbidimetric method, and platelet adhesion was evaluated by the Baumgartner perfusion method. RPR110885 was administered IV at dosages of 30 and 60 μg/kg of body weight, and bleeding time, platelet aggregation responses, and platelet count were determined at hourly intervals for 4 hours.

Results

Both RGDS and RPR 110885 inhibited platelet aggregation in vitro in dose-dependent manner and inhibited platelet adhesion to subendothelial collagen. The concentration of RGDS that inhibited platelet aggregation by 50% (IC50) was 100 to 142 μM for the various agonists tested, whereas the concentration of RPR 110885 that inhibited platelet aggregation by 50% was 0.03 to 0.05 μM. When administered to ponies at 30 or 60 g/kg, RPR 110885 almost completely inhibited ADP-induced platelet aggregation.

Conclusions

RGDS and RPR 110885 inhibited equine platelet function; however, RPR 110885 was several thousand times more potent than RGDS.

Clinical Relevance

RGD-containing peptides may be useful for treatment of thrombotic diseases of horses. (Am J Vet Res 1997;58:457–460)

Free access
in American Journal of Veterinary Research

Summary

The protective immunity induced by 3 experimental FeLV vaccines were evaluated: Prototype inactivated FeLV vaccine developed from a molecularly cloned FeLV isolate (FeLV-faids-61E-A); a mixture of immunodominant synthetic peptides corresponding to regions of the FeLV-Gardner-Arnstein-B (FeLV-GA-B) envelope proteins; and an adjuvant-disrupted but non-activated virus prepared from a non-cloned FeLV field isolate comprised of subgroup A and B viruses (FeLV-05821-AB). Included as controls were parallel groups of cats inoculated with adjuvants alone or with an established commercial FeLV vaccine. After each inoculation and after virulent virus challenge exposure, sera from all cats were assayed for elisa-reactive antibody against purified FeLV, FeLV neutralizing (vn) antibody, and FeLV antigenemia/viremia—viral p27 antigen in serum and within circulating leukocytes. Immunity was challenged by oral/nasal exposure of vaccinated and control cats with FeLV-faids-61E-A or FeLV-05821-AB, an infective. noncloned, tissue-origin, FeLV field isolate containing suhgroup-A and -B viruses. Vaccine-induced immunity was assessed by comparing the postchallenge-exposure incidence of persistent viremia and the pre- and postchallenge exposure titers of vn and elisa antibody in cats of the control and vaccine groups. The percentage of cats that resisted development of persistent viremia after FeLV challenge exposure and the preventable fraclion (pf) for the vaccine groups (which adjusts for the severity of the challenge and the degree of innate resistance in the controls) were as allows: adjuvant controls, 26%; FeLV-faids-61E-A inactivated virus vaccine, 95% (pf = 93.2%); FeLV-GA-B peptide vaccine, 5% (−28.4%); FeLV- 05821-AB noninactivated vaccine, 67% (55.4%); and commercial FeLV vaccine, 35% (12.2%). The prechallenge exposure mean vn antibody titer for each group was: <1:8 in the adjuvant controls; 1:43 in the FeLV-faids-61E-A-vaccinated cats; <1:8 in the peptide-vaccinated cats; 1:38 in the noninactivated virus-vaccinated cats group; and 1:12 in the cats vaccinated with the commercial vaccine. Thus, induction of vn antibody in the vaccinated cats, although modest, appeared to be correlated with induction of protective immunity as defined by resistance to FeLV challenge exposure. Results of these studies indicate that inoculation of cats with an experimental inactivated virus vaccine prepared from a molecularly cloned FeLV isolate was most effective in stimulating protective immunity against heterologous and homologous FeLV challenge exposure.

Free access
in Journal of the American Veterinary Medical Association

electrophoretic transfer of these culture-derived E canis antigens to nitrocellulose. Synthetic-peptide–based E canis antigens were synthesized, conjugated to bovine serum albumin, and applied to the nitrocellulose by airbrushing. Immunoblots were blocked with

Full access
in American Journal of Veterinary Research