Table 2.

Functionality of the humoral immune response.

Group	mFc-ACE2 inhibition (%)	mFc-ACE2 inhibition titer (ID50)	Neutralization Titer (D614G strain)	Neutralization Titer (Delta strain)
1.RBDf HBc alum SC	83	1607	640	160
2.RBDf HBc IN	63	122	ND	ND
3.RBDf HBc alum SC/IN	87	2376	320	160
4.RBDf HBc alum SC/IN MIX	86	5535	1280	160
5.CRBDH6_HEK HBc alum SC/IN	86	3330	320	112
6.HBc alum SC/IN	0	0	ND	ND

Serum pools collected fifteen days after the third dose (day 49 of the study) were evaluated in an inhibition ELISA using murine Fc ACE2 (mFc-ACE2) and RBD human Fc molecules. The neutralization titers were determined against SARS-CoV-2, using the VERO E6 cell line. ID50 is the serum dilution where 50% of binding inhibition is attained. ND: non-determined. SC: subcutaneous; IN: intranasal; MIX: simple mixture.