Introduction Characterization of host-pathogen interactions of Streptococcus pneumoniae is important as this pathobiont poses still a danger to human health (1) Monoclonal antibodies (mAb) specific for bacterial proteins are very suitable for precise and reliable microbial and infection-biological studies (2)

Goals. The aim was to establish monoclonal antibodies specific for mainly surface-associated pneumococcal proteins to investigate the interplay between the pathogen and host in detail.

Material and Methods. Mice were immunised with 73 purified recombinant pneumococcal proteins and the obtained hybridomas were screened stepwise in an indirect ELISA using three different antigen preparations: (A) whole pneumococci and pneumococcal lysate; (B) the purified recombinant pneumococcal proteins divided into groups and (C) single proteins according to the positive reaction in step B to enlighten the antibodies' specificity.

Results. So far, mAb specific for >20 different pneumococcal proteins were identified. A high number of them recognise specifically surface-associated proteins of which 10 are specific for lipoproteins, 3 for sortase-anchored proteins, 2 each for non-clasical surface proteins (NCSP) and choline-binding proteins (CBPs) as well as for 4 non-classified proteins. Two mAb are directed against intracellular proteins. A large proportion of the hybridomas created have to be screened in follow up studies.

Summary. The established stepwise screening strategy enables a quick and precise determination of mAb specificity in a targeted and reliable manner. The established mAb will contribute to elucidate the functions of pneumococcal proteins in metabolism and host-pathogen-interactions.

References:

Mehr, S. & Wood, N. Streptococcus pneumoniae – a review of carriage, infection, serotype replacement and vaccination. Paediatr. Respir. Rev. 13, 258–264 (2012)Nelson, P. N. Demystified ...: Monoclonal antibodies. Mol. Pathol. 53, 111–117 (2000)