[Novel vaccines. Vaccinations in the near and distant future]. / Neuartige Impfstoffe. Impfen in naher und ferner Zukunft.

Easy-to-develop vaccines usually induce antibodies against acute, self-limiting infections by stable pathogens. Today, most of these vaccines have been made, and the future diseases to tackle are more challenging: highly variable pathogens, rapidly emerging new infections with the potential of developing into pandemics, or therapeutic applications for chronic infections and cancer which most likely require complex immune responses beyond the induction of antibodies. The impact of scientific and technological progress on vaccinology has multiplied the strategies to improve vaccines. Here, we describe how genome-based approaches have revolutionized the way to identify vaccine antigen candidates, how the vast numbers of candidates can be further ranked by sophisticated gene- and protein-array based screening methods, and how surface proteomics may accelerate this target identification process. Increased structural knowledge of antigens will allow exposing or stabilizing those antigen parts relevant for protection and thereby direct the immune response to them. Improved adjuvants will enhance and bias the immune response to induce the relevant arms of the immune system. In conclusion, thanks to conceptual and biotechnological progress, future vaccines will be safer, more efficient and more complex than those today.

RrgA is a pilus-associated adhesin in Streptococcus pneumoniae.

Adherence to host cells is important in microbial colonization of a mucosal surface, and Streptococcus pneumoniae adherence was significantly enhanced by expression of an extracellular pilus composed of three subunits, RrgA, RrgB and RrgC. We sought to determine which subunit(s) confers adherence. Bacteria deficient in RrgA are significantly less adherent than wild-type organisms, while overexpression of RrgA enhances adherence. Recombinant monomeric RrgA binds to respiratory cells, as does RrgC with less affinity, and pre-incubation of epithelial cells with RrgA reduces adherence of wild-type piliated pneumococci. Non-adherent RrgA-negative, RrgB- and RrgC-positive organisms produce pili, suggesting that pilus-mediated adherence is due to expression of RrgA, rather than the pilus backbone itself. In contrast, RrgA-positive strains with disrupted rrgB and rrgC genes exhibit wild-type adherence despite failure to produce pili by Western blot or immunoelectron microscopy. The density of bacteria colonizing the upper respiratory tract of mice inoculated with piliated RrgA-negative pneumococci was significantly less compared with wild-type; in contrast, non-piliated pneumococci expressing non-polymeric RrgA had similar numbers of bacteria in the nasopharynx as piliated wild-type bacteria. These data suggest that RrgA is central in pilus-mediated adherence and disease, even in the absence of polymeric pilus production.

Corynebacterium lipophiloflavum sp. nov. isolated from a patient with bacterial vaginosis.

A unique coryneform bacterium was isolated from a patient with bacterial vaginosis. Chemotaxonomical investigations demonstrated that the unknown bacterium belonged to the genus Corynebacterium. The yellow-pigmented, slightly lipophilic, oxidative, urea-hydrolyzing bacterium could be phenotypically readily differentiated from the other members of the genus Corynebacterium. Comparative 16S rRNA gene analysis revealed that the bacterium represented a new subline within the genus Corynebacterium for which the name Corynebacterium lipophiloflavum sp. nov. is proposed. The type strain is CCUG 37336 (DSM 44291).