Amyloid Form of Ovalbumin Evokes Native Antigen-specific Immune Response in the Host

• Published in: The Journal of biological chemistry Vol. 290; no. 7; pp. 4131 - 4148
• Main Authors: Tufail, Saba, Owais, Mohammad, Kazmi, Shadab, Balyan, Renu, Kaur Khalsa, Jasneet, Faisal, Syed Mohd, Sherwani, Mohd. Asif, Gatoo, Manzoor Ahmad, Umar, Mohd. Saad, Zubair, Swaleha
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 13-02-2015
• Subjects: Albumin; Amyloid; Antibody; Antigen; Antigen Presentation; Antigen; Albumin; Amyloid; Antigen Presentation; Antibody
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M113.540989

Amyloids are highly organized protein aggregates that arise from inappropriately folded versions of proteins or polypeptides under both physiological as well as simulated ambiences. Once thought to be irreversible assemblies, amyloids have begun to expose their more dynamic and reversible attributes depending upon the intrinsic properties of the precursor protein/peptide and experimental conditions such as temperature, pressure, structural modifications in proteins, or presence of chemicals in the reaction mixture. It has been repeatedly proposed that amyloids undergo transformation to the bioactive peptide/protein forms under specific conditions. In the present study, amyloids assembled from the model protein ovalbumin (OVA) were found to release the precursor protein in a slow and steady manner over an extended time period. Interestingly, the released OVA from amyloid depot was found to exhibit biophysical characteristics of native protein and reacted with native-OVA specific monoclonal as well as polyclonal antibodies. Moreover, antibodies generated upon immunization of OVA amyloidal aggregates or fibrils were found to recognize the native form of OVA. The study suggests that amyloids may act as depots for the native form of the protein and therefore can be exploited as vaccine candidates, where slow antigen release over extended time periods is a pre-requisite for the development of desired immune response.
Background: Amyloids have recently been found to be reversible and dynamic. They release the precursor peptide/protein in a slow and sustained manner.
Results: Antibodies produced in response to amyloid immunization could recognize native antigen.
Conclusion: OVA amyloids release proteins harboring native antigen epitopes.
Significance: The slow and sustained release of native antigen from amyloids makes them potential candidates for inducing a protective antibody response.