Western blot assay (WB) and cross adsorption studies of 2 patients with severe tick-borne rickettsioses in Nîmes, southern France, 2007.

<p>WB procedures were performed as described elsewhere <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000338#pntd.0000338-Jensenius2" target="_blank">[47]</a> using 20 µl of a 1 mg/ml suspension of rickettsial antigen per lane. The cross-adsorption assay using <i>R. massiliae</i> and <i>R. conorii</i> antigens followed by WB on the resulting supernatant was performed as previously described <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000338#pntd.0000338-Jensenius2" target="_blank">[47]</a>. Columns Rc and Rm depict western blots using <i>R. conorii</i> and <i>R. massiliae</i> antigens, respectively. Molecular weights (MW) are indicated on the left (arrow = 135 kDa). Untreated sera is acute sera tested by WB. For patient 1, when adsorption is performed with <i>R. massiliae</i> antigens (columns AdM), it results in the disappearance of homologous and heterologous antibodies. In contrast, when absorption is performed with <i>R. conorii</i> antigens (columns AdC), only homologous antibodies disappear indicating that antibodies are specific for <i>R. massiliae</i>. For patient 2, when adsorption is performed with <i>R. conorii</i> antigens (columns AdC), it results in the disappearance of homologous and heterologous antibodies. However, when it is performed with <i>R. massiliae</i> antigens (columns AdM), only homologous antibodies disappear indicating that antibodies are specific for <i>R. conorii</i>.</p>