SPECIFIC LYMPHOCYTE STIMULATION IN CATTLE NATURALLY INFECTED WITH STRAINS OF BRUCELLA-ABORTUS AND CATTLE VACCINATED WITH BRUCELLA-ABORTUS STRAIN-19

  • 1 January 1978
    • journal article
    • research article
    • Vol. 39  (4) , 585-589
Abstract
Cell-mediated immune responses in cattle naturally infected with strains of B. abortus and in cattle vaccinated with B. abortus strain 19 during calfhood were studied by an in vitro lymphocyte-stimulation procedure. Lymphocytes were prepared from peripheral bovine blood by the Ficoll-diatrizoate technique, suspended in RPMI-1640 medium (1.5 .times. 106 lymphocytes/ml), cultured with B. abortus-soluble antigen or phytohemagglutinin, and incubated for 6 days. At 16 h prior to termination of incubation, cultures were labeled with 1 .mu.Ci of [3H]thymidine (3HdT) and, after harvesting, assayed for 3HdT incorporation into DNA by liquid scintillation spectrometry. Lymphocytes from cattle with bacteriologically confirmed isolation of B. abortus underwent a significantly higher lymphocyte stimulation with B. abortus-soluble antigen than did cattle vaccinated with B. abortus strain 19 during calfhood (P < 0.005). Standard seroagglutination tests were conducted simultaneously with lymphocyte-stimulation tests, but there was no apparent correlation between levels of humoral antibodies and the cell-mediated immune responses as measured by in vitro specific lymphocyte stimulation.