Existence of functional lingual antimicrobial peptide in bovine milk

Abstract

The lingual antimicrobial peptide (LAP) belongs to the beta-defensin family in cattle and is localized in epithelial cells of alveoli in mammary glands. The aim was to investigate whether LAP is secreted into milk and whether the secreted LAP has antimicrobial activity. Decaseinated bovine skim milk was applied to sample extraction cartridges, and the eluate was used for competitive enzyme immunoassay and Western blotting to test for the presence of LAP in milk. After tricine-SDS PAGE, the gel was stained using the periodic acid-Schiff reaction to examine the possibility of glycosylation of LAP. The eluate obtained from the sample extraction cartridges was subjected to a LAP antibody-coupled affinity column, after which the antimicrobial activity of its eluate against Escherichia coli was investigated with radial diffusion plate assay and colony-forming unit enumeration following the culture of bacteria with the sample. The immunoreactive LAP was detected in the eluate by competitive enzyme immunoassay (optical density = 0.437 +/- 0.012 vs. 0.468 +/- 0.016). In the Western blotting analysis, immunoreactive bands were seen around 8, 14, and 17 kDa. The bands at 14 and 17 kDa, but not 8 kDa, were periodic acid-Schiff reaction-positive. The eluate of LAP antibody-coupled affinity column had antimicrobial activity against E. coli (cfu/control = 0.17 +/- 0.18). These results suggest that bovine milk contains functional LAP-like substances that exert antimicrobial activity.

Lingual antimicrobial peptide and lactoferrin concentrations and lactoperoxidase activity in bovine colostrum are associated with subsequent somatic cell count

“…LAP concentration and LPO activity were determined as reported by Isobe et al . (2009a) and Isobe et al . (), respectively.…”

“…Lingual antimicrobial peptide (LAP) is one of the bovine β‐defensins that exists predominantly in cow milk (Isobe et al . 2009a; Kawai et al . ).…”

Exploring the pharmacological potential of promiscuous host-defense peptides: from natural screenings to biotechnological applications

“…Furthermore, HDPs are able to be induced, being another HDP property that could be exploited in their purification (Lavine et al, 2005). In fact, the microbial challenge test of different vertebrates and invertebrates permitted the isolation of augmented HDPs (Isobe et al, 2009). Thus, it could be possible to induce HDPs with a potent anti-proliferative activity against a particular group of pathogens (Lemaitre et al, 1997).…”

Copy number variation of individual cattle genomes using next-generation sequencing

“…Two other beta-defensin-like molecules, Lingual (LAP) and Tracheal (TAP) antimicrobial peptides, were found to have significant CNV among individuals. Both the LAP and TAP peptides are activated in response to bacterial infection and are expressed in a wide range of epithelial tissues, including mammary epithelial cells (Isobe et al 2009;Lopez-Meza et al 2009). CN changes of these alleles may influence host resistance to mastitis, which is an important economic trait in the breeding of dairy cattle.…”