Lymphoscintigraphy of XXXX @entity14 @entity3 in athymic @entity19 by use of radioiodinated B72.3 monoclonal antibody.

@entity1 @entity19 @entity5 @entity6527 @entity3 @entity14 @entity10769
The potential of radioiodinated monoclonal antibody B72.3 for lymphoscintigraphy was evaluated, using suitable animal models of a @entity1 @entity14 . LS174T xenografts were grown at various sites in @entity10769 -pretreated athymic @entity19 , and the development of @entity3 in different organs was assessed histologically. After iv inoculation of the @entity19 , 66% of the animals developed " @entity3 " to the axillary lymph nodes. Of these @entity19 , 100% also developed @entity5 on their backs and 79% had lung micrometastases. Livers, kidneys, and spleens showed no evidence of @entity5 growth. In 33% of the @entity19 in which primary @entity5 had been removed from the hindfoot pad, @entity3 to the popliteal lymph nodes were observed 3 1/2 weeks after @entity5 implantation. BALB/c (nu/nu) female @entity19 bearing axillary and popliteal lymph node @entity3 were used to test the potential of radiolabeled B72.3 antibody (an @entity6527 ) as a lymphoscintigraphic agent. A monoclonal antibody against horseradish peroxidase (also an @entity6527 ), which did not bind @entity5 cells in vitro, served as a control. Both normal and @entity5 -bearing axillary and popliteal lymph nodes imaged up to 6 hours after the sc injection of 20-40 mu Ci of 125I-labeled B72.3 into either the forefoot or hindfoot pads. The localization index (L.I.) (specific/nonspecific antibody in @entity5 divided by specific/nonspecific antibody in blood) for @entity5 in lymph nodes was approximately 1 during the first 6 hours after antibody injection, thus indicating no specific antibody accumulation. Twenty-four hours and later after sc injection, images of nodal @entity3 (14-477 mg) and specific antibody accumulations were observed. At these times the L.I.'s ranged 1.5-3.5. Tumor-negative nodes did not image at 24 hours after injection of 125I-labeled B72.3. The L.I.'s of the normal nodes and of other tissues from these @entity19 were about 1.0 at 24 hours, indicating no specific antibody accumulation. Autoradiographic analysis of lymph nodes containing @entity5 showed heterogeneous antibody distribution of B72.3 within @entity5 sections with heavy patches of antibody accumulation in mucin globules. In lymph nodes the normal lymphocytes adjacent to the @entity5 cells showed no antibody accumulation. The lack of specific, early antibody accumulation by @entity5 -bearing nodes in @entity19 suggests that B72.3 does not accumulate in nodal @entity3 to the degree necessary to consider it a potential agent for use in lymphoscintigraphy.
