TABLE 1.
Comparison of the immunogenicities and vaccine efficacies in mice of three recombinant forms of DbpAN40 in various adjuvant formulations, and the in vitro potencies of their antisera
| Expta | Adjuvantb | Immunogenc | Two immunizations
|
Three immunizations
|
||||
|---|---|---|---|---|---|---|---|---|
| End-point titer
|
Infection prevalenceh | End-point titer
|
Infection prevalenceh | |||||
| DbpA IgGd | Growth inhibitione | DbpA IgGd | Growth inhibitione | |||||
| 1 | Freund's | Lpp:DbpAN40 | 2,048,000 | 1,280 | 0/5g | NDf | ND | ND |
| H6DbpAN40 | 1,024,000 | <160 | 5/5 | ND | ND | ND | ||
| E. coli | 128,00 | <40 | 5/5 | ND | ND | ND | ||
| 2 | Freund's | Lpp:DbpAN40H6 | 512,000 | 80 | ND | 2,048,000 | ND | 0/5g |
| Lpp:DbpAN40 | 256,000 | <40 | ND | 512,000 | ND | 0/5g | ||
| H6DbpAN40 | 512,000 | ND | ND | 512,000 | ND | 0/5g | ||
| E. coli | 4,000 | ND | ND | 2,000 | ND | 5/5 | ||
| TDM/MPL | Lpp:DbpAN40H6 | 256,000 | 40 | ND | 128,000 | ND | 0/5g | |
| Lpp:DbpAN40 | 256,000 | <40 | ND | 256,000 | ND | 2/5 | ||
| H6DbpAN40 | 8,000 | ND | ND | 256,000 | ND | 4/5 | ||
| E. coli | 16,000 | ND | ND | 4,000 | ND | 5/5 | ||
| 3 | Freund's | Lpp:DbpAN40H6 | 2,048,000 | 400 | ND | 1,024,000 | 2,560 | 0/5g |
| Lpp:DbpAN40H6 | 512,000 | 100 | ND | 512,000 | 640 | 1/5g | ||
| E. coli | 4,000 | <25 | ND | 32,000 | <40 | 5/5 | ||
| Quil A | Lpp:DbpAN40H6 | 4,096,000 | 200 | ND | 4,096,000 | >2,560 | 0/5g | |
| Lpp:DbpAN40 | 2,048,000 | <25 | ND | 1,024,000 | 640 | 0/5g | ||
| E. coli | 64,000 | ND | ND | 128,000 | ND | 5/5 | ||
| Alhydrogel | Lpp:DbpAN40H6 | 128,000 | 200 | ND | 128,000 | 2,560 | 0/5g | |
| Lpp:DbpAN40 | 256,000 | <25 | ND | 128,000 | 640 | 0/5g | ||
| E. coli | 4,000 | ND | ND | 2,000 | ND | 5/5 | ||
| Alhydrogel + Quil A | Lpp:DbpAN40H6 | 1,024,000 | 1,600 | ND | 256,000 | >2,560 | 0/5g | |
| Lpp:DbpAN40 | 4,096,000 | <25 | ND | 512,000 | 640 | 1/5g | ||
| E. coli | 2,000 | ND | ND | 2,000 | ND | 5/5 | ||
Immunizations were intraperitoneal in experiment 1 and subcutaneous in experiments 2 and 3.
Freund's, complete Freund's adjuvant for first immunization and incomplete Freund's adjuvant thereafter, TDM/MPL, trehalose dimycolate plus monophosphoryl lipid A.
Immunogens were 20 μg for DbpA or 5 μg for E. coli (negative control).
Values are the means of duplicate ELISA titer determinations against Lpp:DbpAN40 on antisera pooled from the five mice within each immunization group.
Values are the means of duplicate inhibition titer determinations on antisera pooled from the five mice within each immunization group.
ND not determined.
P < 0.05 versus control (Fisher's exact test).
Number infected/number tested.