An invertebrate defense molecule activates membrane conductance in mammalian cells by means of its lectin-like domain.

The invertebrate defense molecule Coelomic Cytolytic Factor-1 (CCF-1) and the mammalian cytokine Tumor Necrosis Factor (TNF) share a similar lectin-like domain that, upon interaction with specific sugars, causes lysis of African trypanosomes. In contrast to TNF, CCF-1 does not require an acidification of a lysosomal compartment for this activity. Moreover, we could demonstrate using the whole cell patch clamp technique that both TNF and CCF-1 activate amiloride-sensitive channels in mammalian cells, in a TNF receptor-independent way, but, unlike TNF, CCF-1 does not require acidic conditions for this activity. These data confirm the functional analogies of an invertebrate defense molecule and a mammalian cytokine, based on a similar lectin-like interaction.