Effect of growth hormone and insulin-like growth factor-I on immunoglobulin production by and growth of human B cells.

The effect of human GH and insulin-like growth factor-I (IGF-I) on immunoglobulin (Ig) production by and proliferation of human B cells was studied in serum- and hormone-free medium. GH enhanced the production of Ig by and thymidine uptake of the human lymphoblastoid B cell lines, CBL and GM-1056. IGF-I, but not IGF-II or insulin, also enhanced Ig production by and proliferation of CBL and GM-1056. However, the GH-induced enhancement was not mediated by IGF-I inasmuch as enhancement was blocked by anti-GH antibody but not by anti-IGF-I antibody or anti-IGF-I receptor antibody. Conversely, the IGF-I-induced enhancement was blocked by either anti-IGF-I antibody or anti-IGF-I receptor antibody but not by anti-GH antibody. GH and IGF-I also enhanced Ig production by and proliferation of the human lymphoblastoid B cell lines, CESS, GM-1500, SKW, and GM-3332. Furthermore, GH and IGF-I enhanced production of IgG1, IgG2, IgG3, IgG4, IgA1 IgA2, and IgM by and thymidine uptake of tonsillar B cells stimulated with Staphylococcus aureus Cowan strain I. Again, the GH-induced enhancement was blocked by anti-GH antibody whereas the IGF-I-induced enhancement was blocked by either anti-IGF-I antibody or anti-IGF-I receptor antibody but not vice versa.