TI - pAb180 and pAb183 inhibit MMP-28 proteolysis . AB - To determine if the anti-MMP28 polyclonal antibodies inhibit MMP-28 activity , 10 nM MMP-28 was pre-incubated with pAb180 or pAb183 at varying concentrations for one hour at 37degC and then assessed for proteolytic activity after 24 hours against an artificial fluorescent pan-MMP SUBstrate . Both antibodies were found to significantly inhibit the activity of MMP-28 at 0.5 : . . . . . . 1 and 3 : . . . . . 1 molar ratio of antibody to MMP28 (Fig 4A) . pAb180 inhibited MMP-28 by 66.2%* at 5 nM and 97.6%** at 30 nM while pAb183 inhibited MMP-28 by 60.3%* at 5 nM and 69.1%* at 30 nM ( * = p <= 005 , ** = p <= 001 ) . When measured through 5 hours , enzymatic activity of 100 nM MMP-28 was inhibited in a dose dependent manner by pAb180 or pAb183 while the activity of human MMP-2 ( 10 nM ) or MMP-10 ( 100 nM ) was not inhibited by the addition of 60 or 100 nM pAb180 or pAb183 , ( Fig 4B ) . No inhibition was detected in MMP-2 or MMP-10 activity following 24 hours under any of the conditions evaluated ( data not shown ) . These data demonstrate that pAb180 and pAb183 are capable of specifically inhibiting the activity of MMP-28 against a synthetic SUBstrate in vitro .