A vaccine composition for birds comprising as an active ingredient a structure containing O-antigen derived from Gram-negative bacteria, provided that said structure does not contain a whole cell, and a process for preparing the same are provided. By using a structure containing O-antigen (e.g. lipopolysaccharide) derived from Gram-negative bacteria as an active ingredient in accordance with the present invention, alleviation of inoculation reaction and reduction in an amount of injection are attained as compared to the conventional whole-cells vaccine to thereby allow for the increase in the number of other antigens to be mixed therewith.
1. A salmonella vaccine composition for birds comprising purified lipopolysaccharide O-antigens from Salmonella Enteritidis, Salmonella Typhimurium , and Salmonella Infantis , provided that said O-antigens are not comprised in a whole cell; and at least one additional antigen selected from the group consisting of an antigen from Newcastle disease virus, an antigen from avian infectious bronchitis virus, an antigen from Mycoplasma gallisepticum , an antigen from Egg drop syndrome virus and an antigen from Haemophilus paragallinarum.
2. The salmonella vaccine composition according to claim 1 , wherein the Salmonella is one or more Salmonella groups selected from the group consisting of O4, O7 and O9.
3. The salmonella vaccine composition according to claim 1 , wherein the O-antigen has at least 5,400 EU/ml from each Salmonella in the vaccine composition.
4. The salmonella vaccine composition according to claim 2 , wherein the O-antigen has at least 5,400 EU/ml from each Salmonella in the vaccine composition.
5. A method for preparing the salmonella vaccine composition of claim 1 , the method comprising:
(1) culturing Salmonella;
(2) releasing the O-antigen from cells in the solution after said culture;
(3) collecting said O-antigen from the solution after said release; and
(4) preparing the solution after said collection to obtain a vaccine composition.
6. The method according to claim 5 , wherein (2) comprises sonication or treatment with phenol.
7. The method according to claim 5 , further comprising inactivating the cells and/or emulsifying the O-antigen.
8. The method according to claim 5 , wherein inactivation is carried out after culturing, and emulsification is carried out after collection.
9. The method according to claim 5 , further comprising measuring an amount of the O-antigen.
10. The method according to claim 9 , wherein the measurement is carried out after collection.
11. The method according to claim 5 , further comprising removing Lipid A.
12. The method according to claim 11 wherein removing Lipid A is carried out after collection.