Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 27, 2001
Publication Date: N/A
Interpretive Summary: The newly introduced brucellosis vaccine strain RB51 induces protection against brucellosis but does not induce a response that can be detected by use of conventional assays. Assays have been developed which can detect the immune response but these assays use cells which we found to give an uneven signal. A detergent extract was found to give the same results as cells but avoided several assay problems found with using cells. The antigen for this new assay can be prepared in any brucellosis laboratory. This test could be used to detect immune responses in vaccinated cattle and could be developed for use in a field test. Testing for vaccination is of importance in wildlife studies and may become important for importation. Large numbers of livestock are imported into the USA from areas which brucellosis is indigenous.
Technical Abstract: Serological responses to the newly introduced rough Brucella abortus vaccine strain RB51 cannot be determined by use of conventional brucellae tests because these tests utilize smooth LPS as the antigen. Antibody to B. abortus RB51 can be detected using gamma-irradiated RB51 cells as the antigen in a dot-blot format. As gamma-irradiated RB51 cells are not easily prepared, we sought to develop an alternative antigen for use in a dot-blot assay. A RB51 antigen was prepared by extraction of B. abortus RB51 with the detergents zwittergent 3-14, Triton X-100, and SDS and tested in a dot-blot assay. When the zwittergent 3-14 extract was used in place of RB51 g-irradiated cells, the titers obtained were either identical to or one dilution higher or lower than those obtained by others using RB51 gamma-irradiated cells. The Triton X-100 and SDS extracts were not good antigens because the extracts interfered with signal development. The zwittergent 3-14 detergent extract of RB51 can be used in place of RB51 cells.