Cytotoxic Activities of Recombinant Soluble Murine Lymphotoxin-α and Lymphotoxin-αβ Complexes

Abstract

Human lymphotoxin-α (LTα) is found in a secreted form and on the surface of lymphocytes as a complex with a second related protein called lymphotoxin-β (LTβ). Both secreted human LTα and TNF have similar biological activities mediated via the TNF receptors, whereas the cell surface LTαβ complex binds to a separate receptor called the LTβ receptor (LTβR). The murine LTα and LTβ (mLTα and mLTβ) proteins have never been characterized. When recombinant mLTα was produced by either of several methods, the protein had a very low specific activity relative to that of human LTα in the conventional WEHI 164 cytotoxicity bioassay The weak activity observed was inhibited by a soluble murine TNF-R55 Ig f..