TNFRSF1A and infection: To further establish a causal relationship between the shedding of TNF-RI and the protection from TNF-α-induced apoptosis, Hec-1-B cells were infected with the pathogenic isolate LNP19995 in presence of 250 pg/ml of sTNF-RI (which is similar to the level of sTNF-RI shedded upon infection with the non-pathogenic isolate LNP21019).