Specific endotoxic lipopolysaccharide-binding proteins on murine splenocytes. I. Detection of lipopolysaccharide-binding sites on splenocytes and splenocyte subpopulations.

Experiments have been carried out using a unique radio-iodinated, disulfide-reducible, photoactivatable LPS derivative (ASD-LPS) to detect specific LPS-binding proteins on murine splenocytes. Fractionation of LPS-photo-cross-linked, reduced, and solubilized splenocyte extracts on two-dimensional polyacrylamide gels has allowed the identification of an 80-kDa LPS-binding protein with approximate pI of 6.5. This LPS-binding protein is present on partially purified populations of splenic B lymphocytes, T lymphocytes, and macrophages. It is also the dominant LPS-binding protein on the murine 70Z/3 B cell line and the YAC-1 and EL4 T cell lines but is not detectable on the undifferentiated murine Sp2/0 myeloma cell line. Of potential importance is the fact that the 80-kDa protein appears to be indistinguishable when photolabeled extracts of splenocytes from the C3HeB/FeJ (lpsn) and LPS-nonresponder C3H/HeJ (lpsd) mice are compared.