Gammopathy in Hamsters with Xenogeneic Tumours

A PREVIOUS communication described the heterotransplantation of human heteroploid cells derived from a prostatic adenoma (MA 160) into nonimmunosuppressed 2-d-old hamsters1. Most animals receiving subcutaneous implants of 107 cells rejected them after 14 d (regressors). In some (27%), however, there was progressive tumour growth (persistors). This was associated with morphological signs of immunological stimulation as evidenced by a pronounced proliferation of plasma cells in lymph nodes, hepatic portal areas, spleen and kidneys. One biological expression of this proliferation was the presence of antibody directed against membrane antigens of living MA160 cells. At the time of peak tumour growth, fluorescent antibody titres as large as 1:1,280 were demonstrated in sera from animals with large tumours.