Several studies have shown the potential contribution of Campylobacteriosis in the development of neuropathies such as the Guillain-Barre �� syndrome. The prominent route of infection is the improper handling and insufficient cooking of poultry. The broad distribution of this pathogen in combination with a high clinical relevance necessitates fast and reliable diagnosis. Although several genomic typing methods exist, these are often timeconsuming and inappropriate for a point-of-care application. Instead, a direct approach detecting the whole bacterium is beneficial. In order to achieve this, copious knowledge of potentially Mechlorethamine hydrochloride suitable targets, i.e. immunodominant proteins, is indispensable. In the past, screening for immunogenic proteins has been carried out on nitrocellulose membranes or using microarray library screening with extensive protein purification. However, these methods have some major drawbacks as the former is prone to non-specific binding and cross-reactivity when using polyclonal sera for screening of bacterial libraries, while the latter method is time-consuming and laborious due to the purification steps needed prior to microarray printing. As we have shown elsewhere, an approach using HaloTagH and specifically coated HaloLinkTM slides is better suited to detect immunodominant proteins while reducing cross-reactivity to a minimum. The HaloTagH provides several advantages to other commonly used tags as it enhances the amount of soluble proteins expressed reducing the Benzoylaconine formation of inclusion bodies. In addition, the interaction of tag and its specific ligand is based on covalent binding. This negates the need for additional purification steps as the crude lysate can simply be spotted onto coated microarrays. Only the target proteins presented as fusion constructs bearing a HaloTagH will bind to the surface, whereas the remaining proteins are washed off. Combining the described screening method with expression libraries derived from C. jejuni cDNA allows for the fast analysis of hundreds of different proteins. Thus, suitable immunodominant proteins can be detected, isolated and identified via sequencing the encoding cDNA sequence. The generation of a cDNA derived expression library offers advantages in contrast to genomic libraries. The latter demand excessive screenings as the genetic information is mostly truncated or of little relevance representing areas within the genome that do not encode for proteins, whereas the former focuses on the genes transcribed. This reduces the amount of clones to be screened. Nevertheless, for effective cDNA library screening normalization is needed, as rRNA is mainly overrepresented due to its extreme abundance within a total RNA extraction prior to reverse transcription. Bacteria only posses a poly-tail on their mRNA in rare cases. Although methods exist to isolate mRNA from bacteria, it is generally considered to be more challenging as compared to eukaryotic RNA, where Oligo primers are sufficient. Therefore, we refrained from isolating the mRNA prior to reverse transcription. Instead, the generated cDNA was normalized, i.e. trimmed down, afterwards by the use of a duplex-specific nuclease. This approach has been shown to effectively reduce the amount of rRNA-derived molecules, thereby altering the overall composition in favour of the mRNAderived cDNA without including a bias. Further optimization of library construction was achieved by using a ligationindependent cloning as well as electroporation, which have been shown to enhance overall cloning efficiency.