Enteric β-Defensin: Molecular Cloning and Characterization of a Gene with Inducible Intestinal Epithelial Cell Expression Associated with
            <i>Cryptosporidium parvum</i>
            Infection

Lingual antimicrobial peptide (LAP), a member of the beta-defensin family in cows, is involved in the innate immune system and plays a crucial role in killing a large variety of microorganisms. The aim of the present study was to demonstrate the immunolocalization of LAP in the mammary glands of cows. A LAP antibody was raised in a rabbit by immunity with a synthetic 11 amino acid sequence out of a 42-amino acid sequence of the mature form of LAP. The specificity of the LAP antibody was checked using a competitive immunoassay and Western blotting. Paraffin sections of the mammary gland were immunostained with LAP antibody. In the competitive immunoassay, an increase of synthetic LAP concentration suppressed the optical density. Western blotting analysis for LAP revealed the presence of the LAP peptide in mammary alveolar tissue. When the mammary gland was immunostained with LAP antibody, epithelial cells of both infected and non-infected alveoli were immunopositive. These results indicate that LAP is localized in the epithelium of non-infected as well as infected alveolus in the mammary gland in cows.

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“…2004), tracheal antimicrobial peptide (TAP, Diamond et al. 1991) and enteric β‐defensin (EBD, Tarver et al. 1998).…”

Section: Introductionmentioning

confidence: 99%

Immunolocalization of lingual antimicrobial peptide (LAP) in the bovine mammary gland

Isobe

Hosoda

Yoshimura

2009

Animal Science Journal

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“…The ␤-defensins differ from the classical or ␣-defensins by the ordering of the three disulfide bonds between the six cysteine residues of the mature peptides (6,27). The ␤-defensins contribute to a protective barrier on mucosal surfaces including the tongue, nasal, and intrapulmonary airways and the small intestine (10,12,26,29). In vitro, defensins exhibit broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria, fungi, and enveloped viruses (6).…”

mentioning

confidence: 99%

Production of β-Defensin Antimicrobial Peptides by the Oral Mucosa and Salivary Glands

Mathews¹,

Jia

Guthmiller³

et al. 1999

Infect Immun

348

208

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β-Defensins are cationic peptides with broad-spectrum antimicrobial activity that are produced by epithelia at mucosal surfaces. Two human β-defensins, HBD-1 and HBD-2, were discovered in 1995 and 1997, respectively. However, little is known about the expression of HBD-1 or HBD-2 in tissues of the oral cavity and whether these proteins are secreted. In this study, we characterized the expression of HBD-1 and HBD-2 mRNAs within the major salivary glands, tongue, gingiva, and buccal mucosa and detected β-defensin peptides in salivary secretions. Defensin mRNA expression was quantitated by RNase protection assays. HBD-1 mRNA expression was detected in the gingiva, parotid gland, buccal mucosa, and tongue. Expression of HBD-2 mRNA was detected only in the gingival mucosa and was most abundant in tissues with associated inflammation. To test whether β-defensin expression was inducible, gingival keratinocyte cell cultures were treated with interleukin-1β (IL-1β) or bacterial lipopolysaccharide (LPS) for 24 h. HBD-2 expression increased ∼16-fold with IL-1β treatment and ∼5-fold in the presence of LPS. Western immunoblotting, liquid chromatography, and mass spectrometry were used to identify the HBD-1 and HBD-2 peptides in human saliva. Human β-defensins are expressed in oral tissues, and the proteins are secreted in saliva; HBD-1 expression was constitutive, while HBD-2 expression was induced by IL-1β and LPS. Human β-defensins may play an important role in the innate defenses against oral microorganisms.

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“…While several β‐defensins were subsequently isolated from other vertebrate species using similar protein‐based methods, the rate of expansion of the gene family was accelerated by the introduction of nucleic acid‐based strategies that identified new β‐defensin genes through sequence homology. Numerous studies described the amplification of new β‐defensin genes with polymerase chain reaction (PCR), using cDNA sequences of known β‐defensins to design PCR primers (39–41). Interestingly, this method was most frequently successful when the primers used to amplify a new gene were derived from a β‐defensin in a different species rather than from the same species.…”

Section: Introductionmentioning

confidence: 99%

“…This finding suggests that such an approach is more suited to the discovery of β‐defensin orthologs (genes that perform the same function in different species and would therefore be expected to share more conserved sequence) than to paralogous β‐defensin genes, which perform similar functions within a species and consequently may show more sequence divergence from one another. Along similar lines, several groups reported using nucleic acid hybridization screens at low stringency to identify new β‐defensins, using sequence from known β‐defensins across and within species as cDNA probes (39, 42).…”

Section: Introductionmentioning

confidence: 99%

Genomics‐based approaches to gene discovery in innate immunity

Scheetz

Bartlett

Walters

et al. 2002

Immunological Reviews

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The completion of draft sequences of the human and mouse genomes offers many opportunities for gene discovery in the field of immunology through the application of the methods of computational genomics. One arm of the innate immune system includes the antimicrobial peptides that protect multicellular organisms from a diverse spectrum of microorganisms. The beta-defensins comprise an important family of mammalian antimicrobial peptides. To better define the beta-defensin gene family, we developed an approach to search genomic databases for conserved motifs present in the beta-defensin family using HMMER, a computational search tool based on hidden Markov models (HMMs), in combination with the basic local alignment search tool. The approach was first used to identify candidate second-exon coding regions, and later applied to finding associated first exons. This strategy discovered 28 new human and 43 new mouse beta-defensin genes in five syntenic chromosomal regions. Within each syntenic cluster, the gene sequences and organization were similar, suggesting that each cluster pair arose from a common ancestor and was retained because of conserved functions. These findings demonstrate an important proof-of-principle for a genome-wide search strategy to identify genes with conserved structural motifs. Such an approach may be readily adopted to address other questions of relevance to immunology.

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Enteric β-Defensin: Molecular Cloning and Characterization of a Gene with Inducible Intestinal Epithelial Cell Expression Associated with Cryptosporidium parvum Infection

Abstract: Volume 65, no. 10, p. 4191, column 1, lines 31 and 32: ". . . genes in knockout mice lacking endogenous mouse class II molecules" should read ". . . genes in transgenic mice with a B10.M background."

Cited by 27 publications

References 0 publications

Immunolocalization of lingual antimicrobial peptide (LAP) in the bovine mammary gland

Immunolocalization of lingual antimicrobial peptide (LAP) in the bovine mammary gland

Production of β-Defensin Antimicrobial Peptides by the Oral Mucosa and Salivary Glands

Genomics‐based approaches to gene discovery in innate immunity

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