- CD137-deficient mice have reduced NK/NKT cell numbers and function, are resistant to lipopolysaccharide-induced shock syndromes, and have lower IL-4 responses. Vinay, D.S., Choi, B.K., Bae, J.S., Kim, W.Y., Gebhardt, B.M., Kwon, B.S. J. Immunol. (2004)