Cytotechnology, 24A177-182, 1997.


Lysozyme stimulates immunoglobulin production by human-human hybridoma and human peripheral blood lymphocytes.

Fumimori Murakami, Takeshi Sasaki, and Takuya Sugahara


Abstract

Lysozyme [EC 3.2.1.17] derived from hen egg white stimulated immunoglobulin production by human-human hybridoma, HB4C5 cells producing human lung cancer specific monoclonal IgM. IgM production by HB4C5 cells was enhanced more than 13-fold by the addition of lysozyme at 380 ƒĘg/ml in a serum-free medium. The immunoglobulin production stimulating effect of lysozyme was observed immediately after inoculation and maintained for 5 days. Lysozyme enhanced immunoglobulin production by the hybridoma line without growth promotion. This enzyme also accelerated IgM and IgG production of human peripheral blood lymphocytes 5.3-fold and 2.3-fold, respectively. These results suggest that lysozyme stimulates immunoglobulin production of not only specific hybridoma line, but also non-specific immunoglobulin producers. However, the enzymatic activity of lysozyme was almost lost by heat-treatment at 100Ž for 30 min, IPSF activity was retained. This fact suggests that IPSF activity of lysozyme does not come from its enzymatic activity or reaction products. All these findings clearly indicate that lysozyme has a novel function as immunoglobulin production stimulating factor.