TABLE 3.

Anti-BSA antibody titers in sera of BALB/c mice immunized with M. smithii TPL archaeosomes containing increasing amounts of DMPC-DMPG^a

DMPC-DMPG (wt %)	Vesicle diam (nm)	Vesicle/ injection (mg [dry wt])	Anti-BSA titerb
			Day 20	Day 35
0	180 ± 81	1.19	409.6 ± 29.1	638.1 ± 90.2
50	186 ± 57	0.86	198.8 ± 37.4c	411.1 ± 62.5
90	152 ± 54	1.14	125.9 ± 11.4c	184.8 ± 15.3c
100	126 ± 56	1.01	57.9 ± 21.3c	139.48 ± 39.5c

^aMice (three per group) were immunized by i.p. injections (days 0, 14, and 31) of various liposome vesicles containing 12.5 μg of encapsulated BSA. Vesicles were prepared from M. smithii TPL, DMPC-DMPG (1.8:0.2 mol%), or mixtures shown as weight percent made from these two compositions. 

^bThe humoral response determined as titer (endpoint dilution at 0.3 optical density units) of IgG plus IgM antibodies in sera ± standard error of the mean. Sera from mice in the Ag-alone control groups (12.5 μg of BSA in PBS/injection) had anti-BSA antibody titers of <25 and 64.9 ± 53.9 on days 20 and 35, respectively. 

^cSignificantly different (P < 0.01) from titer for 100% M. smithii vesicles (0% DMPC-DMPG) as calculated by Student's t test.