**MORE INFO**  
In an effort to make my question as short as possible, I abbreviated too much. This is the complete sentence that originated my question: 

> 少年時代から２０年間もずっと過ごしてきて、他人**から**軽んじられるの**に**慣れていなかった。  

Now you can see what I clipped. I removed important information. Sorry I caused confusion. I've learned how to ask questions better.

**ORIGINAL QUESTION**


> (1) イギリス人**に**軽{かろ}んじられた。  
> (2) イギリス人**から**軽んじられた。

Both appear to be grammatically correct 受{う}け身形{みけい} and also have the same meaning:  
*"I was looked-down upon by English people."*  

> (3) 虎**に**食べられた。  

Appears to be grammatically correct 受け身形 and mean:  
*"I was eaten by a tiger."*  

So, if I can swap "から" for "に" in #1 and #2, can I do the same with #3 and say:  
> (4) 虎{とら}**から**食{た}べられた。  

 #4 does not sound possible to me *(but maybe it is?)*.  
So, might it be that "に" is the standard/safe thing to use in 受け身形?  
Sometimes, "から" can be swapped for "に", but you'd need a native ear to sense when that is appropriate?