Simultaneous stimulatory and inhibitory effects of an anti-tumor vaccine depending on the size of the tumor target

DANIELA R. MONTAGNA; CHIARELLA PAULA;; ALEJANDRA DUARTE; RAÚL A. RUGGIERO

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2019

EFFECT OF AN ANTITUMOR VACCINE ON THE GROWTH OF TWO TUMORS OFDIFFERENT SIZEImmune-checkpoint inhibitors and antitumor vaccines may produce both tumor inhibitoryand tumor-stimulatory effects on growing tumors depending on the stage of tumor growth.These paradoxical results might be explained assuming the involvement of thephenomenon of tumor immunostimulation that consists in strong immune response (IR)producing inhibition and weak IR inducing stimulation of tumor growth. Herein, we studiedthe effect of an increase of the immune response inmice bearing two tumors of different size that is when the primary tumor was >500 mm 3(established tumor) and when the secondary tumor was incipient (implanted when theprimary tumor was between 500-1000 mm 3 ). We used the strongly immunogenicmethylcholanthrene-induced MC-C fibrosarcoma. Results were expressed as tumorvolume (mm 3 ) [media ± SE] at day 20 of primary tumor growth (7 day of secondary tumor).A significant tumor enhancement was observed in the primary tumor (p