Hideyo, if we talk of INJECTED interferon, Feline Interferon works on cats exactly the same way Human Interferon works on humans... Provided that there isn't yet an extensive database about Feline Interferon on cats like the huge amount of information that we have for Human Interferon (because VO is too young a product and the numbers of the "patients" involved are way too different, of course...) we know that the problems that Human Interferon COULD cause (and sometimes causes) in humans are basically the same that Feline Interferon COULD cause in cats, because the mechanism of action is the same (but keep present, anyway, that to date even the mechanism of action of Human Interferon on humans has been NOT fully understood yet...) You cannot inject Human Interferon to a cat simply because the DNA of humans is alot too different from the DNA of cats, and vice versa. The principle of action of orally-given Interferon (human or feline is just the same) in cats is that it acts basically as an immunostimulant, i.e. it is "seen" by the organism as "foreign matter", causing it to raise its *general* defenses, essentially "shooting at anything that moves", including the FELV/FIV virus... and that's all. No magic. When injected, Interferon acts more directly as an ANTIVIRAL: this is the reason for the two very different levels of results for the two modes for administering it, oral or injected. You can easily perceive that a molecule that is intended to be put DIRECTLY in the bloodstream to kill a virus without killing the host organism at the same time, must be much, much more compatible with it than a molecule that is intended to enter the organism with the "safety net" of the digestive system in between, to act just as a dummy target for the "bullets" of the immune system, where the hope is that the bullets hit the real target (the virus) in the background of the stage where the dummy target moves :)
Sorry for my very poor explanation. Paolo
