From the biologically active extract (G-90) isolated from the tissue homogenate of Eisenia foetida immunoglobulin-like structures were isolated and named G-90/4. 2. G-90/4 in nanogram concentrations stimulated cell proliferation more than did the original G-90. It lyses cells in microgram concentrations. 3. G-90/4 acts as an adhesion molecule between the receptors of adjacent cells. 4. The increase in proliferative activity was accompanied by the elevation of cytoplasmic protein containing tyrosine. 5. Immunohistochemical analyses confirm immunoglobulin-like transmembrane structures in the connective and muscular tissues of E. foetida.
