Immunological function of adhesive glycoprotein from rat ascites hepatoma cells: production of macrophage chemotactic lymphokine.

As previously described, a cell surface-associated adhesive glycoprotein capable of inducing not only aggregation of hepatoma cells but also adhesiveness was separated from differentiated rat ascites hepatoma AH136B cells (forming cell islands in vivo) and highly purified by chromatography. The factor functioned as a mitogenic lectin on rat T lymphocytes. Undifferentiated rat ascites hepatoma AH109A cells (present as single cells in vivo) were unable to synthesize the factor. Distinct macrophage chemotactic activity was released in vitro from rat lymphocytes stimulated by this factor; it was detected in culture supernatant stimulated by 1 microgram/ml of the factor, becoming maximal by 10 micrograms/ml. The activity became detectable in 6 hr after stimulation, reaching its peak in 24 hr. Production of this type of chemotactic lymphokine was suppressed by puromycin (2.0 micrograms/ml). It was heat-stable, nondialysable, stable for freeze-thawing and had an approximate molecular weight of 12,500 on gel filtration; it was derived from nylon wool-non-adherent cells (T lymphocytes). AH136B tumour after subcutaneous transplantation was clearly small in size but the skin site was characterized by marked macrophage and lymphocyte reactions; AH109A tumour after similar transplantation was much larger in size but the cell reaction in the skin site was apparently less marked, suggesting an involvement of the lymphokine in the mediation of macrophage reaction in the tumour site.