Post-Panning Computer-Aided Analysis of Phagotope Collections Selected with Neurocysticercosis Patient Polyclonal Antibodies Separation of Disease-Relevant and Irrelevant Peptide Sequences

The homology of peptide sequences selected from a 7mer phage display library with antibodies elicited by the multicelled parasite Taenia solium in cerebrospinal fluid and serum of neurocysticercosis (NCC) patients and by antibodies of uninfected control patients with similar neurological complications of other ethiology (non-NCC) were analyzed using a PILEUP-Tudos sequence alignments program. The analysis generated dendrograms bearing two types of sequence clusters, those containing (1) only NCC patients-derived peptides and (2) both NCC- and control non-NCC - patient derivatives. By using ELISA, peptides that were selected by the antibodies were identified predominantly in the NCC-derived clusters. In repeated analysis in which sequences were added or removed, the first type of clusters maintained their structure, while the second type of clusters were split into many separate homology units dispersed throughout the guide tree. These results are interpreted as the ability of the analysis to segregate NCC-specific peptide sequences from other sequences. Altogether, this study demonstrates the high potential of the PILEUP-Tudos computer program to analyze phagotope collections recovered through biopanning with polyclonal antibodies elicited in patients by complex and as yet unknown multiple pathogenic antigens and to separate all phagotopes that are disease-relevant on the basis of the sequence homology.