( ( ( CD4 and ) CD8 ) ( ( are ( proteins ( that ( allow ( ( T cells ) ( to ( interact ( with ( MHC ( complex molecules ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP CD4) (CC and) (NNP CD8)) (VP (VBP are) (NP (NP (NNS proteins)) (SBAR (WHNP (WDT that)) (S (VP (VBP allow) (S (NP (NNP T) (NNS cells)) (VP (TO to) (VP (VB interact) (PP (IN with) (NP (NNP MHC) (JJ complex) (NNS molecules))))))))))) (. .)))
CD4 and CD8 are proteins that allow T cells to interact with MHC complex molecules.
(ROOT (S (NP (NNPS Proteins)) (VP (VBP are) (NP (NP (JJ complex) (JJ organic) (NNS molecules)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (PRT (RP up)) (NP (NNS cells))))))) (. .)))