Role of integrin β 1 ‐like protein in proliferation and differentiation of cultured stem cells from midgut of Heliothis virescens

Cultured midgut cells from Heliothis virescens larvae were incubated with anti‐human integrin β 1 made in rabbit and then passed over a column of magnetic beads bound to anti‐rabbit IgG (MACS, Miltenyi Bergisch Gladbach, Germany). Cells bound to integrin β 1 antibody also bound to the anti‐rabbit IgG on the magnetic beads (MACS) and were retained in the column while it remained in the magnetic field. Non‐bound cells were eluted at this time. They did not stain with anti‐integrin antibody just after elution. Removing the column from the magnetic field allowed cells bound to the beads‐integrin β 1 antibody to be eluted. All of these cells stained with human anti‐integrin β 1 upon elution. Each cell fraction was cultured in medium for 3 days. During this time, the populations of cells tended to return to heterogeneous staining patterns characteristic of control populations. However, cells that did not stain immediately with anti‐integrin β 1 antibody exhibited double the rate of multiplication and 8 times more differentiation than the integrin‐antibody positive cells that eluted later, as well as the non‐treated control cells. In a second experiment, midgut cells were incubated for 4 days with various titers of human anti‐integrin β 1 to block surface integrin β 1 ‐like reactive sites. Stem cells blocked with anti‐integrin β 1 antibody during incubation exhibited double the rate of differentiation than non‐treated control cells and those showing anti‐integrin β 1 ‐positive stain upon elution. Arch. Insect Biochem. Physiol. 61:55–64, 2006. Published 2006 Wiley‐Liss, Inc.