|Foote, Monica - IOWA STATE UNIV, AMES|
|Fowler, M - LAND O'LAKES, IA|
|Miller, B - LAND O'LAKES, IA|
Submitted to: ARS Immunology Workshop
Publication Type: Abstract Only
Publication Acceptance Date: December 3, 2003
Publication Date: December 3, 2003
Citation: Nonnecke, B.J., Foote, M.R., Fowler, M.A., Miller, B.L., Waters, W.R. 2003. Nutritional plane affects antigen-induced proliferation of lymphocyte subsets in milk replacer-fed calves vaccinated with M. bovis bacillus calmette-guerin (bcg)[abstract]. ARS Immunology Workshop. Paper No. 17:35. Technical Abstract: National Research Council recommended nutrient requirements for the neonatal dairy calf do not support optimal growth, and may compromise immune function. In a preliminary study, dietary energy and protein were shown to modulate in vitro production of interferon-gamma and nitric oxide by polyclonally stimulated blood lymphocytes from milk replacer-fed calves. We also have shown that adaptive (i.e. Th1-dependent) immune responses of milk replacer-fed neonatal calves vaccinated with Mycobacterium bovis bacillus Calmette Guerin (BCG) and challenged with purified protein derivative (PPD) are comparable in magnitude to adult responses. Using this sensitization/challenge model, effects of nutritional plane on antigen-induced proliferation of T cells from milk replacer-fed calves were evaluated. Holstein bull calves were fed a standard (ST, 0.57 kg/d of a 22% crude protein, 20 % fat, n=4) milk replacer or an intensified (INT, 1.14 kg/d of a 28% crude protein, 20% fat milk replacer, n=4) milk replacer for 7 wk. Calves and four juvenile steers (5-6 mo of age) were vaccinated with M. bovis BCG at the initiation of the study. During the experimental period, average daily weight gain was greater for INT than ST calves (0.68 and 0.32 kg/d, respectively). Proliferation of CD4+, CD8+, and gamma/delta TCR+ T cell subsets in PPD- and mitogen [pokeweed mitogen (PWM) and concanavalin A (ConA)]-stimulated cultures of peripheral blood mononuclear cells (PBMC) acquired before and 7 wk after vaccination were evaluated using flow cytometry. Recall responses to antigen were absent in all treatment groups prior to vaccination. Seven weeks after vaccination, PPD-induced proliferation of CD4+ and gamma/delta TCR+ cells from vaccinated calves exceeded responses of T cell subsets from vaccinated steers. In addition, antigen-induced proliferative responses CD8+ cells from INT calves exceeded those of ST calves. Lymphocytes from young adults were generally more responsive to mitogenic (i.e. ConA and PWM) stimulation than were cells from neonates. Overall, these results suggest that the proliferation of T cell subsets essential in CMI is affected by nutritional plane during the neonatal period.