Negative energy balance does not decrease expression of leukocyte adhesionor antigen-presenting molecules in cattle

Sixteen yearling Holstein steers were fed for 210 or 60% of maintenance req uirements to impose positive or negative energy balance, respectively Blood was collected and analyzed for serum concentration of nonesterified fatty acids (NEFA), and leukocytes were isolated and counted. Isolated leukocytes were then analyzed for expression of the adhesion molecules L-selectin (CD 62L), Mac-1 (CD11b and CD18), and major histocompatability complex (MHC) cl ass I and class II molecules with immunostaining and how cytometric analysi s. Negative energy balance increased the concentration of NEFA in serum (P < 0.0001). Expression of CD62L on neutrophils was increased 14% during nega tive energy balance (P = 0.03). Energy balance did not affect expression of CD62L on any other cell types or expression of CD11b or CD18. Negative ene rgy balance did not affect MHC class I expression but resulted in a small b ut significant increase in the expression of MHC class II (P = 0.03). The r esults of this study provide little evidence that nutritionally created neg ative energy balance impairs expression of CD62L, CD11b, and CD18 or expres sion of MHC class I or MHC class II molecules by resting bovine blood leuko cytes.