Fig. 4.

Lymphocyte proliferation assay determined by incorporation of tritiated thymidine defined as counts per minute of radioactivity. Lymphocytes collected from eight calves at 21 and 28 DPI were not stimulated (medium alone) or stimulated with rAg5 (3.0 μg/mL). Three calves (Nos. 22, 23, 73) were immunized with rAg5, and control calf 18 received adjuvant with control protein (A), whereas three calves (Nos. 19, 20, 21) were immunized with natural Ag5 isolated from a preparative acrylamide gel, and control calf 19 received adjuvant plus preparative gel lacking protein. Error bars represent one standard error of the mean (n = 3).