Giardia lamblia, a parasitic protozoan responsible for diarrhea and malabsorption in humans, grows axenically only in media that contain serum and a high concentration of L-cysteine. During our attempts to grow Giardia in the absence of serum, we found that: (a) human insulin-like growth factors (especially IGF-II), but not insulin, promote the growth and L-cysteine uptake by G. lamblia trophozoites; (b) the growth stimulation was inhibited by αIR3, an anti-type 1 IGF receptor monoclonal antibody, but an anti-type 2 IGF receptor antibody had no effect; and (c) IGFs act on Giardia through a type 1 IGF receptor-like protein, which can bind IGF-II with higher affinity than IGF-I, and most likely possesses intrinsic phosphotyrosine kinase activity.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - May 6 1994|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology