single cell RNA-sequencing
(1) Subcutaneous immunization (10 micrograms of RBD protein +50 microliters of Freund's complete adjuvant) was performed on young (8-10 weeks old) and old (80-90 weeks old) mice. Meanwhile, the mice (80-90 weeks old) in the experimental group were treated with oral yeast cell wall-derived nanoparticles (120 mg/kg) once every two days for a week. One week later, the ingugroin lymph nodes of the mice were collected for single-cell sequencing analysis. The lymph nodes of the young mice were described as "Vac (8-10 wo)" in Figure 2 of the manuscript. The description of lymph nodes in aged mice is "Vac (80-90 wo)". The experimental group was described as "Vac+YNPs" in Figure 3. (2) The aged mice (80-90 weeks old) were divided into the control group and the experimental group, and subcutaneous immunization was carried out respectively (10 micrograms of RBD protein +50 microliters of Freund's complete adjuvant). Meanwhile, the mice in the experimental group were treated with oral yeast cell wall-derived nanoparticles (120 mg/kg) once every two days for a week. The control group was treated with an equal volume of PBS solution. Subsequently, on the 14th and 28th days respectively, an enhanced immune response was conducted (5 micrograms of RBD protein +50 microliters of incomplete Freund's adjuvant). On the 50th day, the inguinal lymph nodes of the mice were collected for single-cell sequencing. The control group was described as "Vac" in Figure 4 of the manuscript, and the lymph nodes of the elderly mice were described as "Vac+YNPs". (3) Mice were divided into a control group and an experimental group. Mice in the experimental group were treated with oral yeast cell wall-derived nanoparticles (120 mg/kg) once every two days for a week. The control group was treated with an equal volume of PBS solution. One week later, the intestinal tracts of the mice were collected for single-cell sequencing. The control group was described as "UnTx" in Figure 5 of the manuscript, and the lymph nodes of the elderly mice were described as "YNPs".