HSF1 and infection: To test whether tbb-6 might be part of an immune response separate from the UPRmt, we assayed Ptbb-6::GFP expression in isp-1(qm150) worms upon RNAi knockdown of four genes reported to mount cellular defenses against infection: elt-2 [69], fshr-1 [70], hsf-1 [71] and zip-2 [72].