[The purification and isolation of a new type of rabbit-origin lipopolysaccharide binding protein and the study of its biological function in vitro].

OBJECTIVE

To isolate and purify a new type of lipopolysaccharide binding protein (LBP) from burn rabbit serum, and to investigate its biological functions.

METHODS

Rabbits subjected to burn injury and endotoxemia were employed. The serum from the rabbits was purified by two-steps of ion-exchange chromatography (Bio-Rex 70 Resin, Mono-Q) and gel chromatography. Furthermore, the serum was identified by flow cytometry analysis, agglomeration test with sheep erythrocyte, and amino end amino acid residue sequencing. The obtained protein was applied to cultured human monocytes (U937), and the cytokine secretion such as TNFalpha from the U937 was observed.

RESULTS

The molecular weight of the harvested protein was 48 kDa, and the 10 amino acid sequence at N end was arranged as GSQGTFTSEE, which was different to the amino acid sequence in NCBI protein bank and was so named P48. P48 possessed similar function to that of LBP and could promote the binding of LPS in a very low concentration with peripheral blood monocytes (PBMC), and also promote the TNFalpha secretion from U937.

CONCLUSION

P48, a new type of LBP, could be isolated and purified from the burn rabbit serum. P48 possessed similar biological activities to that of LBP and could promote the process of inflammatory reaction.