Immunogenic bacterial vesicles with outer membrane proteins

12:

• The process of claim 11, wherein the bacterium is N. meningitidis.

13:

• The process of claim 12, wherein the N. meningitidis is from serogroup A, B, C, W135 or Y.

14:

• The process of claim 11, further comprising a step of formulating the vesicles released by said bacterium into a vaccine composition.

16:

• The process of claim 15, wherein the bacterium also has a knockout mutation of at least one further gene.

17:

• The process of claim 15, wherein the bacterium is E. coli.

18:

• The process of claim 17, wherein the bacterium is a pathogenic E. coli.

19:

• The process of claim 18, wherein the pathogenic E. coli is an extraintestinal pathogenic bacterium, a uropathogenic bacterium, or a meningitis/sepsis-associated bacterium.

20:

• The process of claim 16, wherein the bacterium is E. coli.

21:

• The process of claim 20, wherein the bacterium is a pathogenic E. coli.

22:

• The process of claim 21, wherein the pathogenic E. coli is an extraintestinal pathogenic bacterium, a uropathogenic bacterium, or a meningitis/sepsis-associated bacterium.

23:

• The process of claim 15, wherein the bacterium is a pathogenic Escherichia coli bacterium, which does not express a protein of the Tol-Pal complex and/or which has a knockout mutation of its mltA gene.

24:

• The process of claim 23, wherein the E. coli bacterium is a tolR-strain.