Adjuvants to increase immunogenicity of SARS-CoV-2 RBD and support maternal-fetal transference of antibodies in mice

Author(s)

Lima, Gabrielle Gimenes ; Portilho, Amanda Izeli ; De Gaspari, Elizabeth

• Document type: Journal article
• Source: PATHOGENS AND DISEASE; v. 80, n. 1, p. 13-pg., 2022-10-19.

Abstract

Adjuvant to improve SARS-CoV-2 humoral response and maternal-fetal transference. Adjuvants are important components of vaccines, increasing immunogenicity and modulating the immune response. SARS-CoV-2 vaccines are still being developed in order to improve worldwide access to immunization. Specific populations should be addressed in these investigations, such as pregnant women-to protect both mothers and neonates. In this study, female adult mice were immunized with Receptor-binding domain (RBD) from SARS-CoV-2 adjuvanted by a mixture of DDA and Saponin and put to mating to verify the maternal transference of IgG. For comparison, other group received RBD adjuvanted by OMVs from Neisseria meningitidis and Alum. The adjuvants enhanced IgG production and neutralization. DDA/Sap contributed to increase IgG1, IgG2a, IgG2b, and IgG3 isotypes. Total IgG avidity was considered high, as well as IgG1, IgG2a, and IgG2b avidity. IgG antibodies were effectively transferred to the offspring, predominantly IgG2a, IgG2b, and IgG3. The passive transferred immunoglobulin maintained the neutralizing ability, although it lost avidity. ELISA data was confirmed in Dot-ELISA and immunoblotting assays. DDA and Saponin seem a promising adjuvant mixture to enhance the humoral response of SARS-CoV-2 antigens. Further studies considering the effects of maternal immunization in the protection of offspring are needed, regardless the platform used in COVID-19 vaccines. (AU)

• FAPESP's process: 18/04202-0 - Study of the immunogenicity of outer membrane antigens of Neisseria meningitidis and interaction with cationic lipids: evaluation of new adjuvant for Neisseria meningitidis in different strains of elderly mice
• Grantee: Elizabeth Natal de Gaspari
• Support Opportunities: Regular Research Grants