I've been trying to figure out how to go about immortalizing some primary alveolar macrophages harvested from mice. What I am seeing in the literature is that it seems like people have been using a virus called J2, which has v-myc and v-raf and was derived from Moloney murine sarcoma virus. My question is, why this method? Why not mTERT or SV-40? (I have seen one paper demonstrating loss of phenotype/normal behavior from macrophages immortalized using SV-40.) The first paper I'm seeing that used J2 was published 30+ years ago. I am surprised I haven't come across a newer method and I'm worried my search is biased.