title: Preliminary association analysis of TLR9 gene polymorphisms and immune parameters in an Italian Holstein calves population.
abstract: BACKGROUND
  This preliminary study was aimed at evaluating the association between single nucleotide polymorphisms (SNPs) on Toll like receptor 9 (TLR9) gene and some immunological parameters in a population of Italian Holstein calves.
  
  
  METHODS
  The study was carried out in a commercial farm on 68 Holstein calves aging about 6 months. Genomic DNA was extracted from peripheral blood mononuclear cells (PBMC) and genotyped for nine SNPs on TLR9. Immunological parameters considered were the immunoglobulin (Ig) G titers against bovine herpesvirus 1, and the proliferative response of peripheral blood mononuclear cells to mitogens. For the association study, only results relative to the SNP located in the promoter region have been discussed.
  
  
  RESULTS
  Among the nine SNPs expected, only eight were detected. Considering the SNP located in the promoter region, all three possible genotypes were observed, and their distribution was as follows: genotype a (n=34), b (n=19), and c (n=8). On the basis of their response to vaccine, calves were categorized as low (L, n=8), medium (M, n=45) and high responders (H, n=8). Although no significant association was found between genotypes and L, M or H categories, the genotype estimated as the less represented within the population (c) had no calves categorized as H, the highest frequency of L (25%), and mean values of IgG lower (P < 0.005) compared to genotype b. Furthermore, IgG titers were positively correlated with responses of PBMC to mitogens.
  
  
  CONCLUSIONS
  Genotype c appeared to be "non advantageous" in terms of immune response. It was characterized by the presence of the mutation in homozygosity and, not surprisingly, it was the most rare genotype in the population. Larger studies are necessary in order to confirm these observations.
authors.affiliation: Dipartimento di Produzioni Animali, Università degli Studi della Tuscia, Viterbo, 01100, Italy. nicgio@unitus.it.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Catalani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Nardone
authors.forename: Antonino
authors.initials: A
authors.lastname: Barone
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Scicluna
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Autorino
authors.forename: Andrea
authors.initials: A
authors.lastname: Caprioli
authors.forename: Nicola
authors.initials: N
authors.lastname: Lacetera