A derivative of a 55 kDa extracellular protein from Photobacterium damselae subsp. piscicida is the basis for a vaccine against Photobacterium infection, and thereby protects fish from pasteurellosis.
1. A method of preparing a vaccine against pasteurellosis, comprising:
(a) growing Photobacterium damselae subsp. piscicida cells to mid-exponential phase in culture;
(b) separating supernatant from the cells, where a 55 kDa apoptogenic protein is the major protein present in the supernatant; and
(c) inactivating the supernatant with an inactivating agent.
2. The method of claim 1 , where the culture contains iron at a concentration of less than 15 μM.
3. The method of claim 1 , where the culture contains iron at a concentration of less than 10 μM.
4. The method of claim 1 , where the culture contains iron at a concentration of less than 1 μM.
5. The method of claim 1 , where the culture contains iron at a concentration of less than 0.1 μM.
6. The method of claim 1 , comprising concentrating the supernatant prior to inactivating the supernatant.
7. The method of claim 1 , comprising incorporating the supernatant that has been inactivated into a vaccine.
8. A method of preparing a vaccine against pasteurellosis, comprising:
(a) growing Photobacterium damselae subsp. piscicida cells to mid-exponential phase in culture;
(b) separating supernatant from the cells, where a 55 kDa apoptogenic protein is the major protein present in the supernatant;
(c) concentrating the supernatant;
(d) inactivating the supernatant; and
(e) incorporating the supernatant into a vaccine.
9. The method of claim 8 , where the culture contains iron at a concentration of less than 15 μM.
10. The method of claim 8 , where the culture contains iron at a concentration of less than 10 μM.
11. The method of claim 8 , where the culture contains iron at a concentration of less than 1 μM.
12. The method of claim 8 , where the culture contains iron at a concentration of less than 0.1 μM.
13. A method of preparing a vaccine against pasteurellosis, comprising:
(a) growing Photobacterium damselae subsp. piscicida cells to mid-exponential phase in a culture that is not supplemented with iron;
(b) separating supernatant from the cells;
(c) purifying a 55 KDa apoptogenic protein from the supernatant;
(d) inactivating the protein; and
(e) incorporating the protein into a vaccine.
14. The method of claim 13 , where the 55 kDa apoptogenic protein is the major protein present in the supernatant.
15. The method of claim 13 , where the culture contains iron at a concentration of less than 15 μM.
16. The method of claim 13 , where the culture contains iron at a concentration of less than 10 μM.
17. The method of claim 13 , where the culture contains iron at a concentration of less than 1 μM.
18. The method of claim 13 , where the culture contains iron at a concentration of less than 0.1 μM.