ARS | Publication request: DIFFERENCES BETWEEN BLOOD MONONUCLEAR LEUKOCYTE (MNL) POPULATIONS OF NEONATAL CALVES AND ADULT COWS

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 1996
Publication Date: N/A

Technical Abstract: Neonates are more susceptible to infectious diseases than adults. The objective of this study was to characterize the phenotype and in vitro functional capacities of MNL from calves during the first week of life and compare these characteristics with those of MNL from adult cows. Populations of MNL from neonates had differing T-cell subsets, B-cell, and monocyte percentages than did MNL populations from adults. Functionally, mitogen-stimulated adult MNL produced 100-fold more interferon-gamma (IFN) and 5- to 6-fold more IgM than identically stimulated cultures of neonatal MNL. These differences are likely due to the immaturity of the neonatal immune system and suggest the neonatal MNL are less functionally responsive than adult MNL. Mitogen-induced IFN production and DNA synthesis, and percentages of major histocompatibility (MHC) class II positive cells were lowest in MNL from calves 1 to 4 days of age. These results indicate there is a period of hyporesponsiveness of the immune system soon after birth which may contribute to the elevated susceptibility of the calf to infectious diseases.