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. 2023 Sep 27;26(10):108033. doi: 10.1016/j.isci.2023.108033

Figure 4.

Figure 4

Intranasally immunized Delta-RBD or Omicron-S protein induced potent mucosal IgA antibody responses

Immunized B6 mice were collected for bronchoalveolar lavage (BAL) fluid one month after the last immunization, and tested by ELISA for SARS-CoV-2-specific IgA antibodies.

(A) IgA antibodies specific to the Delta-RBD protein.

(B) IgA antibodies specific to the Omicron-S protein.

The ELISA plates were coated with the respective protein, and the IgA antibody responses were reported as OD450 values. The data are shown as mean ± s.e.m. of five mice in each group. Delta-RBD-i.m. or Delta-RBD-i.n. indicates Delta-RBD protein intramuscular or intranasal immunization. Omicron-S-i.m. or Omicron-S-i.n. indicates Omicron-S protein intramuscular or intranasal immunization. S-i.m. + RBD-i.n. indicates i.m. priming with the Omicron-S protein followed by i.n. boosting with the Delta-RBD protein. Controls, PBS with relevant adjuvants injected via i.m., i.m. + i.n., or i.n. route. The experiments were repeated twice, and similar data were acquired.