Evidence of a laminin binding protein on the surface of Leishmania donovani

Abstract

Both the promastigote and amastigote forms of the intracellular parasite,Leishmania donovanibind the basement membrane glycoprotein laminin with high affinity (K_d= 3.56 × 10^-9M and 3.98 × 10^-9M respectively) with ~9000 and ~800 sites per cell. Bound laminin was identified by direct autoradiography and the binding protein through analysis of the parasite extract by SDS-PAGE and immunoblotting. A major component of 67 kDa was detected. The same protein was obtained when parasite outer membrane proteins were adsorbed to laminin-sepharose affinity matrix and subsequently eluted with SDS. The binding affinity of the isolated receptor was similar to that of the whole cells. Such a receptor isolated inLeishmaniafor the first time, may function as one of the bridging molecules for extracellular matrix recognition.