( ( Polyclonal antibodies ) ( ( are ( isolated ( from ( ( the serum ) ( of ( an ( immunized animal ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Polyclonal) (NNS antibodies)) (VP (VBP are) (VP (VBN isolated) (PP (IN from) (NP (NP (DT the) (NN serum)) (PP (IN of) (NP (DT an) (JJ immunized) (NN animal))))))) (. .)))
Polyclonal antibodies are isolated from the serum of an immunized animal.
(ROOT (S (NP (DT An) (NN animal)) (VP (VBZ produces) (NP (JJ polyclonal) (NNS antibodies)) (PP (IN after) (NP (NP (NN exposure)) (PP (TO to) (NP (DT a) (JJ microbial) (NN antigen)))))) (. .)))