[Immunotherapy of human retinoblastoma with RGNTF-monoclonal antibody using nude mice as model]

Retinoblastoma in nude mice as an animal model was developed by injecting cultured human retinoblastoma cell line(Rb) Y79 into the anterior chamber of eyeball. It was treated by direct injection of RGNTF-McAb into the Rb tumor. Ten out of 30 eyeballs with Rb inoculation did not develop tumor (32% inhibition) if Rb cell suspension was mixed with the RGNTF-McAb before injection; whereas in the control, all 40 but 3 eyeballs developed tumor (7%) when Rb cell suspension alone had been injected. This 32% of inhibition of Rb tumor formation by RGNTF-McAb was very significant (T > 2.58, P < 0.01). The results of immunotherapy of 46 eyeballs with Rb tumor developed 10 days after inoculation by RGNTF-McAb for 2 months revealed that the proportion of grade III-IV tumors before and after therapy reduced from 53% to 26% and that of grade I-II tumors increased from 47% to 74%. Feulgen DNA staining of tumor sections after therapy revealed that the average DNA contents in Rb cells decreased significantly (P < 0.01) from 16.2 +/- 2.6 in grade III-IV to 5.3 +/- 1.2 in grade I-II compared to that of the untreated control 18.8 +/- 3.2. Numerous white cells infiltrating the Rb tumor, hyperplasia of fibrous tissues, and no spreading and metastasis of the tumor tissue were observed in the treated eyeballs; whereas Rb tumor was spreading to the optic nerve and superior colliculus in the untreated eyeballs. Therefore, the RGNTF-McAb can not only inhibit the growth of Rb cells but also limit their spreading and metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)