Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2003
Publication Date: 6/22/2003
Citation: EICHER, S.D., JOHNSON, T.R., MCMUNN, K.A. IN VITRO MODULATION BY BETA-GLUCAN AND ASCORBIC ACID OF BLOOD LEUKOCYTE TOLL-LIKE RECEPTOR AND ACUTE PHASE CYTOKINE EXPRESSION. JOURNAL OF DAIRY SCIENCE. 2003. V. 86(SUPPL.1): P. 192.
Technical Abstract: The objective of this study was to determine if in vitro stimulation of whole blood leukocytes with beta-glucan plus ascorbic acid was dependent on the age of the calf. Blood samples were taken from 12 non-transported Holstein calves at 1, 3, 7, 10, 14, 18, 21, 24, and 28 d-of-age. Leukocytes were stimulated with ascorbic acid (0.3 ug/ml)and beta-glucan (0.4 ug/ml) for 1 h and RNA extracted. The RNA was subjected to real-time RT-PCR for quantification of the expression of interleukin-1 (IL-1) and its receptor antagonist (IL-1Ra), tumor necrosis factor-alpha (TNF), and toll-like receptors 2 and 4 (TLR2 and TLR4). TLR2 and TLR4 had treatment effects (P<.05), but not day or treatment by day interactions. TLR2 was greater (P<.05) for treated cells on day 7, 14, and 24 and tended (P<.10) to be greater on day 10. In contrast, TLR4 was only greater for treated cells on day 7 (P<.05) and tended to be (P<.10) on day 24. IL-1 had a treatment main effect and a treatment by day interaction (P<.05), but IL-1Ra had main effects for treatment and day (P<.05), but only a trend (P<.10) for a treatment by day interaction. IL-1 was greater for treated cells (P<.05) on all but day 4. IL-1Ra was greater (P<.05) for treated cells only on days 1, 7, 10, and 24. TNF was only different for a main effect of day (P<.05), but not for treatment or treatment by day interaction. Only IL-1 and its receptor antagonist expression were stimulated on day 1. On days 7 and 24 all tested receptors and cytokines had increased RNA expression. So, it appears that there are periods during which the blood leukocytes may be refractory for increased RNA expression of cytokines and toll-like receptors in response to beta-glucan and ascorbic acid stimulus. These data enhance our understanding of the biological kinetics of the developing neonatal calf immune system, so that management procedures can occur at the best possible times.