January 1, 2010.
Pneumonic plague, caused by the gram-negative bacteria Yersinia pestis, has led to millions of human causalities during several major pandemics and has the potential to be employed as a deadly biological warfare agent. For this reason, it is vital that an effective vaccine against Y. pestis be created. Currently, a subunit vaccine exists which works by stimulating B-cells (humoral immunity), but it has failed to protect primates in aerosolized bacterial challenges. In an effort to complement the existing vaccine, an alternative vaccine strategy can use both B-cell stimulation and the targeting of T cells (cell-mediated immunity) with an antigenic peptide isolated from the bacteria. To determine what proteins may stimulate T cells, bacteria from three different strains of Y. pestis, KIM 5, KIM 6, and KIM 8, were cultured on TBA plates for four days and then in BCS liquid medium at either 26 or 37C for four hours. Subproteomic fractionation of different regions of Y. pestis cultures were obtained and examined using 2-D DIGE, size-spin filters, and mixed-mode chromatography to isolate protein fractions that may stimulate T cells. Once differential proteins are selected, future work includes determining structure by mass spectrometry, and testing for antigenic peptides on T4 and T8 T cell stimulation assays.
Lawrence Livermore National Laboratory (LLNL)