We are using the antibody for detection of LAMB3 out of human Kerationocyte cell lines. Is it possible that also shorter versions of LAMB3 are detected?
some antibodies regularly have some non-specific binding, look up the specs and see if this is the case for this antibody. Also, is there a possibility that there are ubiquitinated or sumoylated...etc. forms of this protein which could be conjugated? If so, then you would see your free protein and conjugated at different band weights. There could also be cleaved forms of the protein, find out if this protein undergoes a cleavage reaction in certain circumstances.