What antibody to use? Conjugated vs. unconjugated?

[curious1]

Hi,

Sorry if this seems to be a simple question but how do we know what kind of antibodies to use? I mean what is the difference between conjugated and unconjugated and how do we know which one to use? So, if we have an unconjugated primary antibody do we need to use an unconjugated secondary? Also, as far as dilutions go for the antibody, the information sheet says 1:500 for ascites, 1:1000 for purified Ig, and 1:500-1:1000 for polysera. My antibody is monoclonal unconjugated so which one do I follow? What does ascites mean? Does polysera mean polyclonal? There's so much I don't understand!