Molecular changes in lymph node tissue after skin heterografts.

Changes in the rat lymph node RNA base composition and in ribosomal aggregation induced by heterologous skin graft have been characterized by the base composition analysis of the phenol extractable RNA, by the density gradient centrifugation of the ribosomal particles and by amino acid incorporation in the newly synthetized protein. Following skin grafts, the changes in base composition of total RNA in lymph . nodes were mainly due to the synthesis of ribosomal type RNA. Ribosomes were assembled as single units or as polyribosomes. The present findings also show an increase in amino acid incorporation by polyribosomes after the first graft reaction.