Profiles of immune system antibodies provide a comprehensive viewpoint to develop a broad-spectrum pneumonia and meningitis vaccine.
Vaccine Development using Protein Microarray
A vaccine trains an individual’s immune system to recognize the disease-causing bug as a threat. Robust vaccination creates an immune response to any variant of the bug the individual might encounter throughout life. The bacteria Streptococcus pneumoniae causes pneumonia and meningitis, while a vaccine exists, it does not work against all variants or strains of the bacteria. Without adequate immune defense around a million people die from the diseases each year. Previously, vaccine development was limited by an incomplete catalog of Streptococcus pneumoniae strains and no technique to characterize antibodies created in an immune response. Campo et al. demonstrate a solution by using a protein microarray to capture immune responses from samples collected during testing of a new S. pneumoniae whole-cell vaccine in phase I clinical trial.
The protein microarray was fabricated on Oncyte nitrocellulose film slides to detect antibodies that interacted with proteins from the disease-causing bug. 42 Clinical trial participants were vaccinated using a whole cell vaccine predicted to broaden defense to S. pneumoniae strain variants. By exposing individuals to proteins similar in all strains whole cell vaccine offers an improvement to existing options.
Immune snapshots were captured as each individual responded to the vaccine. Samples from participants were screened for antibodies that recognize any one of 6613 proteins on the panproteome microarray. Interestingly, vaccinated individuals had antibody ‘fingerprints’ a pattern of IgG immune proteins that likely represent previous exposure to the bug. Fingerprints were revealed using multi-dimensional clustering approach and were maintained throughout the trial, independent of vaccine dose. By separating participant data into cohorts based on vaccine dose, 138 proteins were identified that created a statistically significant change in IgG binding. Protein characteristics were functional diverse, including cell wall metabolism, signal peptides, and transporter proteins among 72 unique categories. This approach was used to identify surface associated proteins as these candidates may be important for easy access by the immune system. This data provided promising preliminary results to correlate efficacy to specific vaccine components to fuel development of specific and sensitive vaccines.
For more information: https://elifesciences.org/articles/37015