Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 6, 1995
Publication Date: N/A
Excisional biopsies of the prescapular lymph nodes from cattle were examined by computer-assisted morphometry to determine changes in T-lymphocyte subpopulations following Brucella abortus vaccination. Twenty-four eight-month-old Hereford heifers were injected subcutaneously in the axillary area with 1 X 10**10 live B. abortus strain 19 (S19, n=6) or SRB51 (n=12) suspended in two ml of saline. Six control heifers were injected with sterile saline. Lymph node biopsies were collected at 1, 2, 4, 6, 10, and 12 weeks post vaccination (PV). Five-um cryostat sections were incubated with Mab to CD4 (IL-A11), CD8 (IL-A51), or y/S (IL-A29) bovine T-cell surface antigen and processed for immunoperoxidase staining. Numbers of stained lymphocytes in randomly selected fields were calculated by image-analysis software. There were no significant differences in the number (p=0.07) or relative proportions (p=0.22) of CD4+, CD8+, and y/S+ lymphocytes in SRB51, S19, and control lymph nodes. There was a trend of increased proportion of CD4+ and decreased proportion of CD8+ cells in both vaccine groups, especially at earlier timepoints. The results support other studies indicating lymphocyte depletion is not a sequela of infection with B. abortus vaccine strains.