Hello Bryan

Polyclonal antibodies are more sensitive than monoclonal. There is a high likelihood of detection of the target since multiple epitopes are detected in case of polyclonal antibody. But there is a drawback as far as polyclonal antibody is concerned. It gives high background and cross reactivity mainly due to detection of multiple epitopes. But this can be taken care of using blocking buffer. Moreover polyclonal antibody is less expensive than monoclonal. I feel you should go ahead with polyclonal ab for quantitative Western Blots.

All the best.

In addition to Malcolm, background largely depends on the purity of the polyclonal. Serum or total IgG (as obtained by e.g. Protein A or G purification) will usually give you a higher background (as there are all IgGs from the host animal and thus there is a higher chance of cross-reactivity) than antigen affinity purified antibodies which usually are highly specific. They normally are more expensive (as more efforts are involved), but usually they will give you better results. Monoclonals are more defined, but you'll only have one binding site on your target protein, so your signals usually are weaker.

In any case, you might need to optimize the dilutions of primary and secondary antibodies for optimal results. First, try to find the highest possible conc of your secondary (until you get unacceptable background) and then titer your primary the same way.

Dear Bryan,

Monoclonal antibodies are much better for your aim, since monoclonal antibodies usually give you a single band, which is much more easy to detect and quantify it. Also, when you have a single band you can make sure that it is definitely your target protein. Use the best brands both for your primary and secondary antibodies (e.g. Abcam and Roche) to get the best results.

thank you all so much, this was very helpful