CD44 and neoplasm: Noteworthy, in this TCR-Tg model where large numbers of OT-I cell are present in the periphery, CD8+ responses to an Ova challenge were normal as illustrated by i) the up-regulation of CD44 on the majority of CD8+Vα2+ lymphocytes (Fig. 6A), ii) the prominent in vivo cytotoxic activity against SIINFEKL-pulsed target cells (Fig. 6B) and iii) the rejection of Ova-bearing tumor cells even in naïve [SM-Ova×OT-I]F1 mice (Fig. 6C).