INFRADIAN VARIATION OF RAT THYMIC AND SPLENIC MESSENGER-RNA TO NOVIKOFFS-HEPATOMA

During the immune response to rat tumor cells there is participation o f the thymus and the spleen via the synthesis of antibodies and immune cellular elements. During this process different mRNAs of both organs are synthesized. Here is presented the infradian variation of mRNA sy nthesis of immunized rat thymus and spleen to Novikoff's Hepatoma (NH) cells. These cells were maintained. and transferred in ascitic manner in the peritoneal cavity of Sprague Dawley male rats standardized wit h IZ hours Or) of light and 12 h of darkness. Aliquots of 1 x 10(6) NH dead cells were innoculated intraperitoneally into rats after being e xposed during 30 minutes to ultraviolet light and incubated at 37 degr ees C with 50 U of neuraminidase/ml during 70 minutes. Groups of 3 con trols and 3 immunized mts were killed at the same circadian timepoint (10 a.m.) under anesthesia every 3 days during a span of IF: days. At each lime spleens and thymus of each group were harvested and pooled i n order to isolate their mRNA. Isolation of the rRNA and mRNA of contr ol and immunized rats was performed by affinity chromatography employi ng oligothymidylic acid cellulose columns. Analysis of variance demons trated a significant (p <0.03) higher synthesis of immune (i) mRNA of rat spleen, starting on 3 days after immunization with NH cells and re aching the higher levels on 6 and 18 days after immunization and lower levels an 9, 12, 15 days after immunization. Same effect is also obse rved in the synthesis of imRNA rat thymus 6 days after immunization, h owever, there was not difference with the intact rat thymus mRNA on 3, 9 and 12 days after immunization. Interestingly, there was observed a n increased synthesis of intact rat thymus mRNA 15 days after inoculat ion. During this cyclic synthesis of thymic and spleenic imRNAs it see ms that the spleen plays the role of a possible pacemaker of the coord inated immune response to NH cells.