Table 2.

Summary of RBD-J formulations prepared to evaluate the correlation of in vitro stability of RBD-J with in vivo mouse immunogenicity. Study I (groups #1–4) included unstressed and forced degraded (37 or 70°C heat-stressed and DTT-treated) RBD-J formulated with AH and CpG. The stress condition for each formulation is displayed along with the concentration of antigen and adjuvants. RBD-J (5 mcg) was administered to mice subcutaneously (50 µl). Study II (groups #5–6) included varying doses (5, 1, 0.5 mcg) of unstressed RBD-J adjuvanted with AH+CpG and administered as noted above. Note that the doses of AH and CpG in each group in study I and II were same (75 mcg and 30 mcg, respectively).

			Concentration (mcg/mL)			Dose injected in mice (mcg) Injection volume = 50 µL
Study arm	Group No.	Condition	Total RBD-J	Aluminum adjuvant	CpG	Total RBD-J	Aluminum adjuvant	CpG	No. of mice
I	1	Unstressed (4°C)	100	1500	600	5	75	30	9
	2	37°C for 1 week	100	1500	600	5	75	30	9
	3	70°C for 1 h	100	1500	600	5	75	30	5
	4	DTT	100	1500	600	5	75	30	5
II	5	Unstressed (4°C)	20	1500	600	1	75	30	9
	6	Unstressed (4°C)	10	1500	600	0.5	75	30	9