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Veterinary immunology and immunopathology2009; 130(1-2); 102-106; doi: 10.1016/j.vetimm.2009.01.005

Antimicrobial properties of the equine alpha-defensin DEFA1 against bacterial horse pathogens.

Abstract: Defensins are small effector molecules of the innate immune system, synthesised by various organisms including plants and animals. The peptides act as endogenous antibiotics with an antimicrobial activity against a broad spectrum of microbes including bacteria, fungi and viruses. alpha-Defensins are a subgroup of the defensin family, their synthesis is limited to some tissues and furthermore to some mammalian species including the horse. Equine DEFA1 is an enteric alpha-defensin exclusively produced in Paneth cells. The peptide showed an activity against a broad spectrum of microbes, but typical pathogens of the horse were not included in the previous antimicrobial studies. Here, we report the antibacterial properties of DEFA1 against clinical isolates of typical horse pathogens including Rhodococcus equi, various streptococci strains, Salmonella choleraesuis, and Pasteurella multocida. The recombinantly expressed DEFA1 peptide exerted potent activity against these pathogenic bacteria. The highest susceptibility showed R. equi. Three genetically different strains of R. equi were killed at low micromolar concentrations, comparable with conventionally used antibiotics.
Publication Date: 2009-01-23 PubMed ID: 19211153DOI: 10.1016/j.vetimm.2009.01.005Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

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This research article discusses the antimicrobial properties of the molecule alpha-defensin DEFA1 in horses. The study specifically evaluates how effective DEFA1 is against common pathogens, or harmful bacteria, that affect horses.

Understanding Defensins and alpha-Defensins

This research is centered around defensins, a type of small molecular structure generated as a protective measure by various organisms, including mammals and plants. These tiny molecules:

  • Act as endogenous (internally occurring) antibiotics.
  • Show antimicrobial activity against a variety of microbes, including bacteria, fungi, and viruses.

alpha-Defensins are a specialized subgroup of the defensin family. These are only produced in select tissues and by certain mammalian species, including horses. In equines, DEFA1—an alpha-defensin—is created expressly in Paneth cells, which are located in the lining of the small intestine.

Purpose of the Research

Although DEFA1 seems to be effective against a wide range of microbes, previous studies haven’t included typical horse pathogens. The aim of this research, therefore, is to study the antibacterial properties of DEFA1 against horse-specific harmful bacterias.

Method and Results

The methodology of the research involved:

  • Analysing the properties of DEFA1 against various horse pathogens, namely Rhodococcus equi, different strains of streptococci, Salmonella choleraesuis, and Pasteurella multocida.
  • Using a recombinantly expressed (created by combining DNA sequences) DEFA1 peptide to test its effectiveness on the said pathogens.

The results were positive as DEFA1 showed potent activity against these bacterias. The most responsive was R. equi. Three genetically different strains of R. equi were killed upon exposure to DEFA1, showing it to be as effective as commonly used antibiotics.

Significance of the Research

This research is essential as it highlights DEFA1’s potential application as a new measure to combat bacterial infections in horses, eliminating the need for conventional antibiotics. Further, by understanding how DEFA1 functions, scientists could potentially develop new antimicrobial treatments for various organisms.

Cite This Article

APA
Bruhn O, Cauchard J, Schlusselhuber M, Gelhaus C, Podschun R, Thaller G, Laugier C, Leippe M, Grötzinger J. (2009). Antimicrobial properties of the equine alpha-defensin DEFA1 against bacterial horse pathogens. Vet Immunol Immunopathol, 130(1-2), 102-106. https://doi.org/10.1016/j.vetimm.2009.01.005

Publication

ISSN: 1873-2534
NlmUniqueID: 8002006
Country: Netherlands
Language: English
Volume: 130
Issue: 1-2
Pages: 102-106

Researcher Affiliations

Bruhn, O
  • Institute of Animal Breeding and Husbandry, University of Kiel, Hermann-Rodewald-Strasse 6, D-24118 Kiel, Germany.
Cauchard, J
    Schlusselhuber, M
      Gelhaus, C
        Podschun, R
          Thaller, G
            Laugier, C
              Leippe, M
                Grötzinger, J

                  MeSH Terms

                  • Actinomycetales Infections / drug therapy
                  • Actinomycetales Infections / microbiology
                  • Actinomycetales Infections / veterinary
                  • Amino Acid Sequence
                  • Animals
                  • Anti-Infective Agents / pharmacology
                  • Horse Diseases / drug therapy
                  • Horse Diseases / microbiology
                  • Horses
                  • Microbial Sensitivity Tests / veterinary
                  • Molecular Sequence Data
                  • Pasteurella multocida / drug effects
                  • Pasteurella multocida / growth & development
                  • Recombinant Proteins / pharmacology
                  • Rhodococcus equi / drug effects
                  • Rhodococcus equi / growth & development
                  • Rhodococcus equi / isolation & purification
                  • Salmonella / drug effects
                  • Salmonella / growth & development
                  • Streptococcus / drug effects
                  • Streptococcus / growth & development
                  • alpha-Defensins / pharmacology

                  Citations

                  This article has been cited 4 times.
                  1. Cui C, Li L, Wu L, Wang X, Zheng Y, Wang F, Wei H, Peng J. Paneth cells in farm animals: current status and future direction. J Anim Sci Biotechnol 2023 Aug 15;14(1):118.
                    doi: 10.1186/s40104-023-00905-5pubmed: 37582766google scholar: lookup
                  2. Bruhn O, Grötzinger J, Cascorbi I, Jung S. Antimicrobial peptides and proteins of the horse--insights into a well-armed organism. Vet Res 2011 Sep 2;42(1):98.
                    doi: 10.1186/1297-9716-42-98pubmed: 21888650google scholar: lookup
                  3. Bruhn O, Paul S, Tetens J, Thaller G. The repertoire of equine intestinal alpha-defensins. BMC Genomics 2009 Dec 23;10:631.
                    doi: 10.1186/1471-2164-10-631pubmed: 20030839google scholar: lookup
                  4. Palrasu M, Kakar K, Marudamuthu A, Hamida H, Thada S, Zhong Y, Staley S, Busbee PB, Li J, Garcia-Buitrago M, Nagarkatti M, Nagarkatti P. AhR Activation Transcriptionally Induces Anti-Microbial Peptide Alpha-Defensin 1 Leading to Reversal of Gut Microbiota Dysbiosis and Colitis. Gut Microbes 2025 Dec;17(1):2460538.
                    doi: 10.1080/19490976.2025.2460538pubmed: 39894796google scholar: lookup