Adenovirus serotype 11 causes less long-term intraperitoneal inflammation than serotype 5: Implications for ovarian cancer therapy

- i.p. Ad11 causes less long-term intraperitoneal inflammation than Ad5 in CD46-transgenic mice.
- Ex vivo BALB/c peritoneal macrophages express less RANTES after Ad11 than Ad3 or Ad5 treatment.
- In vivo, cytokine and cellular responses 6 h after i.p. Ad11 are equal to Ad5.
- In contrast, after repeated i.p. application, Ad5, but not Ad11, causes severe i.p. toxicity.
- The use of Ad11 instead of Ad5 might increase patient safety in future virotherapy of ovarian cancer.

In a phase II/III clinical trial intraperitoneal (i.p.) administration of a group C adenovirus vector (Ad5) caused bowel adhesion formation, perforation and obstruction. However, we had found that i.p. group B, in contrast to group C adenoviruses, did not cause adhesions in nude BALB/c ovarian cancer models, prompting further investigation. Ex vivo, group B Ad11 caused lower inflammatory responses than Ad5 on BALB/c peritoneal macrophages. In vivo, i.p. Ad11 triggered short-term cytokine and cellular responses equal to Ad5 in both human CD46-positive and -negative mice. In contrast, in a long-term study of repeated i.p. administration, Ad11 caused no/mild, whereas Ad5 induced moderate/severe adhesions and substantial liver toxicity accompanied by elevated levels of IFNγ and VEGF and loss of i.p. macrophages, regardless of CD46 expression. It appears that, although i.p. Ad11 evokes immediate inflammation similar to Ad5, repeated administration of Ad11 is better tolerated and long-term fibrotic tissue remodelling is reduced.