Which of the following statements about CD4* Th17 cells are true? i. Cannot form T effector memory (TEM) T cell populations ii. Require the master transcription factor RORgammaT for their development iii. Produce effector cytokines IL-17 and IL-22 which help recruit neutrophils and stimulate antimicrobial peptide production iv. Do not require the transcription factor NFAT for IL-2 production downstream of TCR activation v. Important for defense against intracellular bacterial infection only il and iii O ii, iii, iv O i, ii, and iv