Immunoblot analysis of laminin α4 and β2 chains in bone marrow stromal cells.

Protein extracts of the stromal cell lines, HS-5, L88/5, and L87/4 and of LTMCs were separated on 5%-to-15% gradient gels, transferred to nitrocellulose, and incubated with an antiserum against the synthetic peptide KPPVKRPELT corresponding to the human laminin α4 chain or with the mAb C4 against the laminin β2 chain. The antilaminin α4 chain antiserum detected 2 specific bands of 200 and 300 kd in HS-5 cells and in LTMCs but not in L87/4 and L88/5 cells (not shown). A 200-kd band corresponding to the β2 chain could be detected in all stromal cell lysates (L88/5, L87/4, HS-5, and LTMCs) and in an LN-10/11 preparation (LN-10/11), which was used as a positive control.