01420nas a2200217   4500000000100000008004100001260000900042653002600051653002400077653001100101653002800112653001200140653002400152653002500176100001400201245006100215300001100276490000700287520089400294022001401188       2001                            d  c200110aAntibodies, Bacterial10aAntigens, Bacterial10aHumans10aImmunoradiometric Assay10aleprosy10aLipopolysaccharides10aMycobacterium leprae1 aPatil S A00aEnhanced antibody activity in serum depleted of antigen.  a407-110 v223 a<p>Presence of antigen and antibodies in a sample may interfere with the antibody, as well as with antigen detection assays. In such a situation, avidity of the probing antigen or antibody plays the key role in the assay. In the present study, using monoclonal antibodies against a mycobacterial antigen, lipoarabinomannan, patient serum is depleted of mycobacterial antigen by capture immunoradiometric assay and this antigen-depleted serum is tested for anti-lipoarabinomannan antibodies by inhibition immunoradio-metric assay. It is observed that serum, after depletion of antigen, revealed enhanced antibody activity compared to initial levels. It, therefore, appears that the avidity of the probing monoclonal antibody may detach the antigen from the loosely attached complexes and renders the complexed antibody free, thus increasing the reactive antibody molecules in the serum.</p>  a1532-1819