|KRUGER, L - Iowa State University|
|BEITZ, D - Iowa State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2016
Publication Date: 6/9/2016
Citation: Kruger, L.A., Beitz, D.C., Humphrey, S.B., Stabel, J.R. 2016. Cellular responses to Mycobacterium avium, subsp. paratuberculosis in colostrum-deprived and colostrum-replete holstein calves supplemented with fat-soluble vitamins. Meeting Abstract. Kruger, L.A., Beitz, D.C., Humphrey, S.B., Stabel, J. 2016. 13th International Colloquium on Paratuberculosis. p. 41.
Technical Abstract: Immune benefits of colostrum are attributed to passively transferred IgG but also to growth factors, cytokines, antimicrobial peptides, and leukocytes. Non-nutritive compounds in colostrum promote Th2-biased immune responses to early microbial encounters and prevent harmful, inappropriate inflammation in neonatal tissues. Post-natal, nutritional influences such as vitamin A, D3, or E deficiencies may cause dysregulation of immune signaling and decreased integrity of immune responses, thus compromising neonatal health. The present study was conducted to determine if neonatal bovine leukocyte subsets recognize and respond to MAP antigens within the first 14 d of age when immunity of the calf is still partially naive. The study was designed to test the hypothesis that colostrum, vitamin supplementation, or both nutritional treatments alter mononuclear cell function and subsequent responses to MAP antigens. Peripheral blood mononuclear and mesenteric lymph node cells (PBMC and MNL) were obtained from 30 calves that were assigned randomly at birth to treatments: 1) colostrum deprived (CD), 2) colostrum replacer (CR), 3) CR, vitamin A; 4) CR, vitamin D3; 5) CR, vitamin E; 6) CR, vitamins A, D3, E, in a 14 d study. Calves were injected with vitamin supplements and fed pasteurized whole milk (PWM; CD calves) or fractionated CR at birth. Thereafter, all calves were fed PWM fortified with vitamins according to treatment. Calves were orally inoculated with 10**8 cfu of Mycobacterium avium subsp. paratuberculosis (MAP) on d 1 and 3. PBMC and MNL were analyzed by flow cytometry as fresh cells, after 3 d culture with PHA, and after 6 d culture with a whole cell sonicate of MAP. Peripheral gamma delta T cells were identified as a predominant lymphocyte subset, with decreased percentages noted in CD calves. Stimulation of PBMC with PHA increased CD4 and CD8 subsets, whereas the MNL response was dominated by expansion of B cells. PHA and MPS stimulation decreased the relative abundance of gamma deltaT cells among PBMCs, but MNL gamma deltaT cells increased upon stimulation with MPS. These results identify gamma deltaT cells as key early responders to intracellular infection in neonatal calves and suggest that colostrum may be an important mediator of this response.