Antibody profiling identifies novel antigenic targets in spinal cord injury patients.
Recent evidence implicates antibody responses as pivotal damaging factors in spinal cord injury (SCI)-induced neuroinflammation. To date, only a limited number of the antibody targets have been uncovered, and the discovery of novel targets with pathologic and clinical relevance still represents a major challenge.



In this study, we, therefore, applied an unbiased, innovative and powerful strategy, called serological antigen selection (SAS), to fully identify the complex information present within the antibody repertoire of SCI patients.



We constructed a high-quality cDNA phage display library derived from human spinal cord tissue to screen for antibody reactivity in pooled plasma samples from traumatic SCI patients (n = 10, identification cohort). By performing SAS, we identified a panel of 19 antigenic targets to which the individual samples of the plasma pool showed antibody reactivity. Sequence analysis to identify the selected antigenic targets uncovered 5 known proteins, to which antibody reactivity has not been associated with SCI before, as well as linear peptides. Immunoreactivity against 9 of the 19 novel identified targets was validated in 41 additional SCI patients and an equal number of age- and gender-matched healthy subjects. Overall, we found elevated antibody levels to at least 1 of the 9 targets in 51 % of our total SCI patient cohort (n = 51) with a specificity of 73 %. By combining 6 of these 9 targets into a panel, an overall reactivity of approximately half of the SCI patients could be maintained while increasing the specificity to 82 %.



In conclusion, our innovative high-throughput approach resulted in the identification of previously unexplored antigenic targets with elevated immunoreactivity in more than 50 % of the SCI patients. Characterization of the validated antibody responses and their targets will not only provide new insight into the underlying disease processes of SCI pathology but also significantly contribute to uncovering potential antibody biomarkers for SCI patients.
Biomedical Research Institute and transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Martelarenlaan 42, Hasselt, Belgium.
Ilse
I
Palmers
Biomedical Research Institute and transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Martelarenlaan 42, Hasselt, Belgium.
Elke
E
Ydens
Department Neurosurgery, Jessa Hospital, Stadsomvaart 11, Hasselt, Belgium.
Eric
E
Put
Division of Experimental Neurosurgery and Neuroanatomy, Katholieke Universiteit Leuven and University Hospitals Leuven, Herestraat 49, Leuven, Belgium.
Bart
B
Depreitere
Adelante Rehabilitation, Zandbergsweg 111, Hoensbroek, The Netherlands.
Helma
H
Bongers-Janssen
Department of Intensive Care Medicine, Radboud University, Nijmegen Medical Centre, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands.
Peter
P
Pickkers
Biomedical Research Institute and transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Martelarenlaan 42, Hasselt, Belgium.
Sven
S
Hendrix
Biomedical Research Institute and transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Martelarenlaan 42, Hasselt, Belgium. veerle.somers@uhasselt.be.
Veerle
V
Somers
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood*; D000941:Antigens / Q000276:immunology*; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015723:Gene Library; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012698:Serologic Tests; D013119:Spinal Cord Injuries / Q000097:blood* / Q000276:immunology*
D000906:Antibodies; D000941:Antigens
Antibody repertoire; Antigenic targets; Serological antigen selection; Spinal cord injury; cDNA phage display library