Synthetic GPL Peptides for Specific Mycobacterium avium paratuberculosis Detection
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Solution Overview
Problem
Current diagnostic tests for Mycobacterium avium subsp. paratuberculosis (Map) infections face challenges due to cross-reacting antibodies from related mycobacteria, leading to non-specific reactions and the need for costly and time-consuming pre-absorption steps, and existing antigens used in skin tests and gamma-interferon assays produce false positives in young animals.
Innovation Solution
The use of synthetic peptides, such as DPhe-NMeVal-Ile-Phe-Ala-OMe and its derivatives, which mimic the lipopeptide Para-LP-01, for in vitro detection and quantification of specific anti-Map antibodies and T-cell immune responses, allowing for more specific and efficient diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If crude fractions of mycobacteria are used as antigens in ELISA, then the detection sensitivity is improved, but false-positive reactions occur due to cross-reacting antibodies from related bacteria
Solution Approach 1:
The patent segments the crude mycobacterial fraction into specific peptide components (GPL peptides with sequences like D-Phe-D-Allo-Thr-D-Ala-L-Alaninol) that are unique to Map. This segmentation allows the diagnostic test to target only Map-specific antigens rather than using whole crude extracts, thereby maintaining sensitivity while eliminating cross-reactivity with other mycobacteria.
Solution Approach 2:
The patent applies local quality by identifying and utilizing specific structural features of Map's GPL peptides (such as the particular amino acid sequence and lipid composition) that distinguish Map from other mycobacteria. By focusing on these localized unique characteristics rather than general mycobacterial components, the test achieves high specificity while maintaining detection sensitivity.
2Reliability
If pre-absorption with crude fractions from M. phlei is performed to reduce cross-reacting antibodies, then the specificity of ELISA is improved, but the procedure becomes expensive and time-consuming
Solution Approach 1:
The patent extracts and uses only the essential Map-specific GPL peptide antigens directly in the ELISA assay, eliminating the need for pre-absorption steps with M. phlei. By taking out only the necessary diagnostic components (Map-specific peptides) and removing unnecessary procedural steps (pre-absorption), the patent achieves high specificity while significantly reducing both time and cost.
Solution Approach 2:
The patent performs preliminary identification and characterization of Map-specific GPL peptide sequences and structures, allowing these purified peptides to be used directly as antigens without requiring subsequent pre-absorption steps. This preliminary characterization enables the elimination of time-consuming pre-absorption procedures while maintaining diagnostic specificity.
3Measurement precision
If avian or Johnin PPD antigens are used in skin tests and gamma-interferon assays, then the detection of T-cell-mediated immune response is improved, but non-specific reactions occur in young animals
Solution Approach 1:
The patent segments the conventional PPD antigen into specific Map-derived GPL peptides (such as the tetrapeptide or pentapeptide sequences). This segmentation allows the immune assay to detect T-cell responses specific to Map infection rather than general mycobacterial exposure, thereby eliminating non-specific reactions in young animals while maintaining detection sensitivity for Map-specific immunity.
Solution Approach 2:
The patent changes the antigenic parameter from conventional PPD (a mixture of mycobacterial proteins) to specific Map-derived GPL peptides with defined sequences and lipid compositions. This parameter change ensures that the antigen specifically recognizes Map-specific T-cell responses, eliminating cross-reactivity with other mycobacteria in young animals while maintaining the ability to detect Map-induced immunity.
Data Source
Figure 1A~1B
Figure 2
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AI summary
The invention relates to synthetic pentapeptides and lipopentapeptides and to their use for the diagnosis and treatment of diseases resulting from infections by Mycobacterium avium subsp. paratuberculosis .