A new study published in Scientific translational medicine reports on Ebola vaccine-mediated protection of five mucosal vaccine vectors based on human and avian paramyxoviruses. The study exhaustively characterized the antibody response to each vaccine, identifying elevated characteristics and functions in survivors that could serve as a vaccine protection correlate.
The multi-year study, led by Alexander Bukreyev, Ph.D., of the Galveston National Laboratory at the University of Texas Medical Branch (UTMB), examined whether all vaccines conferred protection and produced antibody responses. The team also explored 139 different immune and vaccine response parameters to see who was responsible for improving “survival quality”.
“Testing during outbreaks is difficult due to its sporadic nature, and yet much study needs to be done to determine the most effective vaccine to fight this disease. Establishing the immunity signatures generated by the vaccine remains crucial to design, the evaluation and application of the vaccine, “Bukreyev said.
Research scientist Michelle Meyer, Ph.D., of UTMB was the lead author of the work, Ebola vaccine-induced protection in nonhuman primates correlates with antibody specificity and Fc-mediated effects , which reports the efficacy results of vaccines in cinomolg macaques challenged with EBOV. The five mucosal vaccines tested differed in the degree of protection against death and disease, ranging from disease-free survival to only partial protection.
Meyer points out that vaccines must do much more than allow for survival, with an ideal outcome to stop virus replication and decrease disease. To assess the characteristics of relevant and potentially predictive antibodies for protection, the team used a survival index in the assay that incorporates several parameters of EBOV disease to allow correlations with improved infection outcomes.
“Through an in-depth characterization of the antibody response, we found that, although all vaccines express the same antigen, they differ in multiple respects, and protection correlates appear to be unique to the vaccine platform. Our analysis defined specific RBD antibodies and Fc-mediated immune functions as contributing factors to improved survival, “Meyer said. The lack of correlation with neutralization antibody titers suggests that conventional means of predicting efficacy do not apply to all vaccines.
During the most recent Ebola outbreaks in Sierra Leone and the Democratic Republic of the Congo, more than 300,000 people were vaccinated. Deciphering immune responses to vaccination that correlate with protection is essential to predict the effectiveness of vaccines in humans, Meyer says.
M. Meyer et al., “Ebola vaccine-induced protection in nonhuman primates correlates with antibody specificity and Fc-mediated effects.” Scientific translational medicine (2021). stm.sciencemag.org/lookup/doi/ … scitranslmed.abg6128
University of Texas Medical Office at Galveston
Citation: New study provides data on Ebola vaccine protections (2021, July 14) retrieved July 14, 2021 at https://medicalxpress.com/news/2021-07-ebola-vaccines.html
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