ORIGINAL PAPER Greater expression of TLR2, TLR4, and IL6 due to negative energy balance is associated with lower expression of HLA-DRA and HLA-A in bovine blood neutrophils after intramammary mastitis challenge with Streptococcus uberis Kasey M. Moyes & James K. Drackley & Dawn E. Morin & Juan J. Loor Received: 12 October 2009 / Revised: 10 December 2009 / Accepted: 13 December 2009 / Published online: 14 January 2010 # Springer-Verlag 2010 Abstract Our objectives were to compare gene expression profiles in blood polymorphonuclear cells (PMN) during a Streptococcus uberis intramammary challenge between lac- tating cows subjected to feed restriction to induce negative energy balance (NEB; n =5) and cows fed ad libitum to maintain positive energy balance (PEB; n =5). After 5 days of feed restriction, one rear mammary quarter of each cow was inoculated with 5,000 cfu of S. uberis. Blood PMN were isolated at 24 h post-inoculation from all cows for mRNA expression via quantitative polymerase chain reaction for 20 genes associated with immune response and metabolism. A total of 12 genes were differentially expressed in blood PMN in NEB versus PEB cows. Upregulated genes by NEB were ALOX5AP, CPNE3, IL1R2, IL6, TLR2, TLR4, and THY1, and downregulated genes were HLA-DRA, HLA-A, IRAK1, SOD1, and TNF. Network analysis revealed that TNF was associated with several of the affected genes in NEB cows compared with PEB cows. Results showed that 24 h after intramammary challenge with S. uberis, cows in NEB had altered PMN expression of genes involved with immune response. Our data provide new information on transcriptomic mechanisms associated with NEB and the corresponding inhibition of immune response in lactating dairy cows. Keywords Cattle . Neutrophil . Energy balance . Streptococcus uberis Introduction During the periparturient period, all cows experience some degree of negative energy balance (NEB) due to the increase in feed intake lagging behind the increase in energy demand for growth of the fetus and uterus, parturition, and milk synthesis (Drackley 1999; Ingvartsen and Andersen 2000). The severity and duration of NEB can be characterized by increased circulating non-esterified fatty acids (NEFA) and beta-hydroxybutyric acid (BHBA) and decreased blood glucose concentrations. Evidence indicates that cows experiencing a more severe degree of NEB may be more susceptible to diseases such as mastitis (Moyes et al. 2009a; Perkins et al. 2002; Suriyasathaporn et al. 1999). Mastitis continues to be one of the most costly of all diseases in the dairy industry (Bar et al. 2008). Streptococcus uberis is a major environmental mastitis-causing pathogen Electronic supplementary material The online version of this article (doi:10.1007/s10142-009-0154-7) contains supplementary material, which is available to authorized users. K. M. Moyes : J. K. Drackley : J. J. Loor Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA D. E. Morin College of Veterinary Medicine, University of Illinois, Urbana, IL 61801, USA K. M. Moyes : J. J. Loor (*) Mammalian NutriPhysioGenomics, University of Illinois, 1207 W. Gregory Dr., Urbana, IL 61801, USA e-mail: jloor@illinois.edu J. K. Drackley : D. E. Morin University of Illinois, 1207 W. Gregory Dr., Urbana, IL 61801, USA Present Address: K. M. Moyes Faculty of Agricultural Sciences, Aarhus University, Blichers Allé, P.O. Box 50, Tjele 8830, Denmark Funct Integr Genomics (2010) 10:53–61 DOI 10.1007/s10142-009-0154-7