title: Naturally occurring level of mixed aflatoxins B and G stimulate toll-like receptor-4 in bovine mononuclear cells.
abstract: BACKGROUND
  As common contaminants of agricultural commodities, aflatoxins (AFs) are highly hazardous carcinogenic mycotoxins originating from very common fungi present in the environment. Their effect on bovine key immune-surveillance molecules is unclear.
  
  
  OBJECTIVE
  To determine the in vitro effects of naturally occurring level of AFs on toll-like receptor-4 (TLR4) and viability in bovine peripheral blood mononuclear cells (PBMCs) as a model system for immunotoxicity.
  
  
  METHODS
  Ten healthy dairy cows were selected as a source of PBMCs. The mRNA expression of TLR4 was quantitatively evaluated in PBMCs treated with a mix of 1.0, 0.5, 0.25 and 0.25 ng/ml of AFB1, AFB2, AFG1 and AFG2, respectively, and 10 ng/ml of the well-known TLR4 agonist lipopolysaccharide (LPS) for 0.5, 2, 5 and 18 hours. We also analyzed the viability of PBMCs exposed to AFs by means of the trypan blue exclusion method and the tetrazolium bromide assay.
  
  
  RESULTS
  Compared with control PBMCs, transcription of TLR4 in AFs-treated PBMCs was significantly up-regulated at post-exposure hours (PEH) 2 and 5, but was unchanged at PEH 0.5 and 18. Unsurprisingly, much higher up-regulation of TLR4 transcript was observed in LPS-treated PBMCs at PEH 0.5, 2, 5 and 18. Conversely, the viability of post-AFs and/or LPS-exposed PBMCs revealed no significant changes.
  
  
  CONCLUSIONS
  Naturally occurring levels of AFs result in increased expression of TLR4 mRNA in bovine PBMCs.
  
  
  CONCLUSIONS
  The increased expression of TLR4 mRNA in bovine PBMCs by AFs also emphasizes the need to reduce admissible levels of AFs in feed for preventive measures.
authors.affiliation: a Section of Immunology, Department of Pathobiology, Faculty of Veterinary Medicine , Ferdowsi University of Mashhad , Mashhad , Iran.
authors.forename: Jalil
authors.initials: J
authors.lastname: Mehrzad
authors.forename: Mojgan
authors.initials: M
authors.lastname: Milani
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Mahmoudi
mesh_terms: D000348:Aflatoxins / Q000276:immunology* / Q000633:toxicity; D000818:Animals; D002417:Cattle / Q000276:immunology*; D002470:Cell Survival / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology*; D007963:Leukocytes, Mononuclear; D008070:Lipopolysaccharides / Q000276:immunology*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology*
chemical_list: D000348:Aflatoxins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D051197:Toll-Like Receptor 4