Many of Pb 's effects on the immune system could be explained through activation of the transcription factor , NF-kappa B .
many of pb 's effects on the immune system could be explained through activation of the transcription factor , nf-kappa b .
O O B-atom O O O O B-body_part I-body_part O O O O O O O B-protein_family_or_group I-protein_family_or_group O B-protein_complex I-protein_complex O