|Kimura, K - IOWA STATE UNIV., AMES|
|Kehrli, JR., M - PFIZER, TERRE HAUTE, IN|
Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: April 19, 1998
Publication Date: N/A
Technical Abstract: We previously established a significant decline in several T-cell subset populations and diminished lymphocyte and neutrophil (PMN) function in periparturient dairy cows. We hypothesized that milk production may be an important immunosuppressive factor. To test this hypothesis, we used 10 mastectomized and 8 intact multiparous Jersey cows (all intact cows developed milk fever). Flow cytometry permitted phenotype analysis of peripheral blood mononuclear cells (PBMC) using monoclonal antibodies against T-cell subsets, B-cells, and monocytes. Lymphocyte blastogenesis (LBT), serum IgM and IgGl, and PMN-iodination (IOD) were assayed to assess functional ability of leukocytes. T-cell populations decreased significantly from 27 d before calving until calving in intact cows (CD3 from 51.9 to 40.1%, CD-4 from 29.8 to 24.8%, CD8 from 12.3 to 8.6%, and gamma/delta-T-Cell from 7.2 to 4.4% of the PBMC). In intact cows, monocytes increased at parturition (from 20.1 to 29.0%). In mastectomized cows, only the population of CD3 cells was decreased at parturition (from 51.7 to 49.5%). LBT did not show significant change in both groups. Serum IgM and IgGl decreased significantly at parturition in intact cows, but mastectomized cows did not show any change. PMN-IOD decreased significantly in both groups from 20 d before calving until calving; mastectomized cows recovered to precalving values within 8 d, but intact cows had not recovered even 20 d after calving. The metabolic challenges imposed by the presence of the mammary gland may play a significant role in periparturient immunosuppression of dairy cows.