An object of the present invention is to provide a non-human animal model unresponsive to a mycoplasma-derived lipoprotein/lipopeptide, and a method for screening an inhibitor or a promoter for a response to a mycoplasma-derived lipoprotein with the use of the non-human animal model. A non-human animal model whose function of a gene that encodes a protein such as TLR6 that specifically recognizes a mycoplasma-derived lipoprotein is deficient on its chromosome, for example, a TLR6 knockout mouse, is generated. With the use of the non-human animal model unresponsive to a mycoplasma-derived lipoprotein or an immune cell such as a macrophage derived from the non-human animal model, a subject material and a mycoplasma-derived lipoprotein, a response to a mycoplasma-derived lipoprotein in the non-human animal model or the immune cell is measured/evaluated, and then an inhibitor or a promoter for a response to that is screened.