Don't know if anyone has responded to you on this one. I'm just now catching up from being gone for the weekend.
Caiphas's answer wasn't in subtitles because it was one of the things Mel changed in response to to the critics saying the movie was Anti-Semitic. The response he gives is what the High Priest said in Scriptures "Let His blood be on us and our children" meaning the Jews. Of course Caiphas is trying to spread the blame at that point because ALL the Jews weren't calling for Christ to be crucified, though there were people inciting the crowd to do so.
And to all the people that say that quote is anti-Semitic and brings up the charge of "God-killing", I simply state that even as High Priest, it was waaay above his paygrade to bless or curse entire peoples forever. In other words, other than speaking for himself and those who joined him, he was just running off at the mouth. In fact, his statement was in itself just about blasphemous. But it was certainly no "proof" that justifies anti-Semitism.