THE EFFECT OF THE ANTI-HUMAN AFP SPECIFIC ANTIBODY ON AFP PRODUCING TUMOR LINE (JTG-1) IN NUDE MICE

Abstract

The alpha-fetoprotein (AFP) producing tumor line (JTG-1) in nude mice was established from the human testicular tumor (embryonal carcinoma with seminoma) and maintained by serial transplantation. The present study was carried out to determine the effect of anti-human AFP specific antibody on the growth of the serial transplanted AFP producing tumor.
The tumor blocks (5×5×3mm) were inoculated into the bilateral subcutaneous space on the mice's flank. The nude mice were divided into 3 groups, 5 mice a group; Group A: anti-human AFP specific antibody (1.8mg) was injected twice a week for four weeks after inoculation of tumor blocks, Group B: normal horse serum (1.5mg) was injected by the same way as the group A, Control Croup: saline (0.5ml) was injected by the same way.
These animals were observed daily and the tumor size was measured twice a week in two dimensions. The serial AFP of serum and cystic fluid were determined every week upto 8 weeks after inoculation of the tumor blocks by the RIA method. The histological and immunohistochemical examinations were also performed in every group at 6 weeks after inoculation of the tumor blocks.
The tumor take was at a rate over 95% and spontaneous regression was not observed. The tumor growth was local and usually became cystic in 3 weeks after inoculation, thereafter the tumor growth was rapid in the control group. On the other hand the tumor growth of the group A was slow and the cystic formation was delayed in start.
The AFP levels of the serum and cystic fluid in the group A were lower than those of the group B and the control group every week after injection of anti-human AFP specific antibody.
By the immunohistochemical examination, a slight fluorescence on the AFP producing tumor cell was recognized at 24 and 72 hours after injection of anti-human AFP specific antibody. By the histological examination, the tumor necroses were observed more frequently in the group A than group B and control group.
In conculusion, the inhibitory effect of the anti-human AFP specific antibody on the tumor growth of JTG-1 was recognized.
The AFP levels of the serum and the cystic fluid were remarkably decreased and histologically, more tumor necroses were observed in group A than group B and control group by the injection of the anti-human AFP specific antibody.