Physiological processes rely on initial recognition events between cellular components and other molecules or modalities. Biomolecules can have multiple sites or mode of interaction with other molecular entities, so that a resolution of the individual binding events in terms of spatial localization as well as association and dissociation kinetics is required for a meaningful description. Here we describe a trichromatic fluorescent binding‐ and displacement assay for simultaneous monitoring of three individual binding sites in the important transporter and binding protein human serum albumin. Independent investigations of binding events by X‐ray crystallography and time‐resolved dynamics measurements (switchSENSE technology) confirm the validity of the assay, the localization of binding sites and furthermore reveal conformational changes associated with ligand binding. The described assay system allows for the detailed characterization of albumin‐binding drugs and is therefore well‐suited for prediction of drug‐drug and drug‐food interactions. Moreover, conformational changes, usually associated with binding events, can also be analyzed.

؉ T lymphocytes are a mainstay of antitumoral immune responses, PTVs could be engineered for the transfer of specific tumor antigens provoking tailored antitumoral immunity. Therefore, PTVs can be used as safe and efficient alternatives to gene transfer vectors or live attenuated replicating vector platforms, avoiding genotoxicity or general toxicity in highly immunocompromised patients, respectively. Thereby, the potential for easy envelope exchange allows the circumventing of neutralizing antibodies, e.g., during repeated boost immunizations. V accination is the administration of one or more immunogens, the vaccine, into patients to trigger antigen-specific adaptive immune responses to prevent (prophylactic vaccination) or to treat (therapeutic vaccination) disease. Vaccines can be classified into several subtypes. Among these are live attenuated replicating vaccines, inactivated vaccines, subunit vaccines, DNA vaccines, or recombinant vector vaccines (for review, see reference 1). Wellknown live attenuated vaccines are, e.g., those against measles (2) or mumps (3). These vaccines replicate but have been attenuated to become apathogenic. The immune responses triggered by live attenuated vaccines are similar to those induced by the pathogenic form of the microbe (4, 5) and involve both the cellular and humoral arms of the immune system. However, attenuated replicating pathogens may carry an inherent risk of reversion to the parental virulent form by in vivo passaging during vaccination, as observed for the Sabin strain used as a polio vaccine (6), or may still be pathogenic in highly immunocompromised patients (7), depending on the respective degree of attenuation of the vaccine strains. On the other hand, inoculation of solely proteinaceous antigens (such as the hepatitis B virus vaccine [8]) or antigenencoding genes (as a DNA vaccine) is regarded as safe but relatively inefficient (9).As an alternative to such vaccines, the genes encoding an antigen can be transferred into cells and thereby presented to the immune system by using recombinant vaccine vectors. For that purpose, an attenuated vector is utilized as a carrier for the antigen-encoding sequences of another pathogen. Thereby, they are