( ( As ( they ( may ( block ( cell-to-cell ( viral spread ) ) ) ) ) ) ( , ( ( virus-specific antibodies ) ( ( ( are important ) ( ( early ( in ( ( the course ) ( of infection ) ) ) ) ( before ( viruses ( have ( entered cells ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (PRP they)) (VP (MD may) (VP (VB block) (NP (JJ cell-to-cell) (JJ viral) (NN spread)))))) (, ,) (NP (JJ virus-specific) (NNS antibodies)) (VP (VBP are) (ADJP (JJ important)) (SBAR (ADVP (RB early) (PP (IN in) (NP (NP (DT the) (NN course)) (PP (IN of) (NP (NN infection)))))) (IN before) (S (NP (NNS viruses)) (VP (VBP have) (VP (VBN entered) (NP (NNS cells))))))) (. .)))
As they may block cell-to-cell viral spread, virus-specific antibodies are important early in the course of infection before viruses have entered cells.
(ROOT (S (NP (NNP Tamiflu)) (VP (VBZ inhibits) (NP (NP (NN spread)) (PP (IN of) (NP (NN virus))))) (. .)))