Each positive learn more interaction was validated in a majority of at least 3 independent this website experiments (see material and methods) and is represented by a cross. Empty boxes stand for an absence of detected interaction. Pneumococcal proteins are figured on the
left and the tested mammalian proteins are at the top of the table, those giving no interaction have been grouped at the right of the table. Interaction profile of the choline-binding proteins Elastin is the extracellular matrix component showing the largest number of interactions with Cbps: CbpI, CbpL and CbpF, while collagens interact only with CbpL and laminin only with CbpE (Table 1). The most frequent interactions have been observed with circulating proteins, such as CRP, factor H and plasminogen. Four different Cbps interact with CRP: CbpI, CbpM, CbpJ and CbpL. CbpE and CbpA, interact with factor H, the latter interaction confirming previous results , Plasminogen interacts with CbpE and CbpF (Table 1). Interactions between CbpE Apoptosis inhibitor and laminin or plasminogen
confirm our previous observations to which we add factor H herein . Interaction profile of the LPXTG proteins Even though all expressed LPXTG proteins were produced as soluble recombinant proteins, some of them gave poor purification yield or poor signal detection during the screen. These restrictions led to the abandon in the screen assay of PavB, ZmpA, MucB and PsrP. The selleck most common interactions encountered with the LPXTG candidates involved the collagen IV (PrtA, ZmpB, NanA and spr1806) and the plasminogen (SpuA, Eng, PrtA and spr1806) (Table 1). NanA also interacts with collagens and fibrinogen (Table 1). The interaction
level of NanA with lactoferrin was not significant in our assay contrary to a previous observation . Dose-responses curves We chose to investigate the dose-response of three unstudied Cbps for which we observed host-protein binding functions: the solid-phase assay screening led to the observation that CbpL interacts with collagens, elastin and CRP, CbpI binds to elastin and CRP and CbpM binds only to CRP. In this experiment, 1 μg of each mammalian protein is coated and increasing amounts of pneumococcal proteins is used, from 0.8 to 200 pmoles per well. For all three analyzed Cbps, the interaction with mammalian proteins is dose-dependent (Fig 4). The highest level of binding of CbpL is observed with elastin, intermediate response with collagens and CRP compared with the BSA negative control (Fig 4). These data confirm the results of the screen, and also comfort the “”semi-quantitative”" informations about the level of binding that we obtained from the screen.