( Antigens ( ( can ( be ( ( detected ( ( ( about one ) week ) earlier ) ) ( than antibodies ) ) ) ) . ) )
(ROOT (S (NP (NNS Antigens)) (VP (MD can) (VP (VB be) (VP (VBN detected) (ADVP (NP (QP (RB about) (CD one)) (NN week)) (RBR earlier)) (PP (IN than) (NP (NNS antibodies)))))) (. .)))
Antigens can be detected about one week earlier than antibodies.
(ROOT (S (NP (DT An) (NN antibody)) (VP (MD can) (VP (VB match) (NP (NP (CD one) (NNS types)) (PP (IN of) (NP (NNS antigens)))))) (. .)))