Liposome-entrapped DNA oral vaccines
AssigneeLipoxen Technologies Limited
InventorsGregory Gregoriadis, Yvonne Perrie
Life of this patent
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Abstract
An oral vaccine contain liposomes and complexed or, preferably entrapped, DNA operatively encoding an antigen in which the liposomes are formed from components including cationic compounds and zwitterionic phospholipids. The hydrophobic groups within the liposome forming components must include at least one group which is saturated. This is believed to raise the transition temperature, rendering the liposomes more stable when delivered orally. The compositions have been found to give detectable increased in IgA levels, secreted immunoglobulins of importance in efficacious oral vaccine delivery.
Claims20
Method of eliciting an IgA response in a mammal comprising administering orally to the mammal a composition comprising a nucleic acid operatively encoding an antigen complexed with or entrapped within liposomes formed from liposome forming components comprising
- a) at least one cationic compound
- b) zwitterionic phospholipid consisting of one or two compounds having the general formula II
- in which R3 and R4 are the same or different and are a group of the formula CH3(CH2)e(CH═CH—H2)f(CH2)g — in which f is 0 to 6, each of e and g+3f are 0 to 23 and e+g is in the range 12 to 23;
- R7 is a C1-8 alkanediyl group;
- Y is —O— or a bond;
- X2 is N, P or S;
- m is 3 when X2 is N or P and is 2 when X2 is S;
- and
- the groups R8 are the same or different and are selected from the group consisting of hydrogen, C1-8 alkyl, C6-11 aryl or aralkyl, or two or three of the groups R8 together with X2 form a saturated or unsaturated heterocyclic group having 5 to 7 ring atoms;
- in which at least 25% by mole of the individual liposome forming components have a transition temperature of more than 40° C.,
- wherein the molar ratio of cationic compound to zwitterionic phospholipid is in the range 1:1 to 1:10,
- whereby an IgA response to the said antigen is generated.
Dependencies are inferred from the claim text.