Appeal No. 1999-2634
Application No. 08/108,606
Claim13 is directed to a method of prevention of an enteric infection caused by
enterotoxigenic E. coli bacteria in humans comprising administrating an appropriate
amount for preventing said infection of a vaccine comprising at least one formalin-
inactivated E. coli strain expressing colonization factor antigens and further having
substantially preserved antigenic and hemagglutinating properties of said colonization
factor antigens. Claim 15 further requires that the vaccine of claim 13 further
comprises cholera toxin b-subunit.
The examiner relies on Svennerholm for the teaching that candidate
vaccines for enterotoxin-producing bacteria include bacteria which are inactivated with
formalin treatment or colicin E2. Svennerholm teaches that the inactivation of bacteria
with mild formalin treatment causes complete killing of the bacteria without significant
loss of the antigenicity of the different CFAs (colonization factor antigens) and O
antigens. In addition, Svennerholm teach that both anti-enterotoxin and anti-
colonization factor antibodies can, independently of each other, protect against
experimental enterotoxin-producing E. coli infection and when present together, these
antibody specificities cooperate synergistically in protecting against infection, and that
for maximal efficacy an ETEC vaccine should ideally invoke an immune response that
would effectively interfere with both colonization and toxin action. Paper No. 16, page
5.
Svennerholm, page197, column 3 to page 198 column 4, indicates that
immunization of both animals and human volunteers with a colicin treated E. coli strain
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