[In vivo imaging analysis of biodistribution of FITC-labeled Rituximab in lymphoma-bearing nude mice].

OBJECTIVE: To conduct an in vivo optical imaging analysis of the biodistribution of antibody Rituximab in lymphoma tumor-bearing nude mice. METHODS: Laser scanning confocal microscope and flow cytometry were employed to determine the affinity of FITC-labeled Rituximab (FITC-Rituximab) with human lymphoma Raji cells. And the in vivo optical imaging system was used to analyze the biodistribution of FITC-Rituximab in lymphoma-transplanted xenograft nude mice. RESULTS: The results of flow cytometry and laser scanning confocal microscope demonstrated that FITC-Rituximab had remarkable affinity with lymphoma Raji cells and was mainly bound at cell membrane. The results of in vivo imaging analysis suggested that FITC-Rituximab could specifically accumulated at peritumor tissue less than 1 h, then penetrated into the interior of tumor and concentrated in 3-4 h. And the specific concentration of FITC-Rituximab could still been observed more than 8-10 h whereas there was no apparent fluorescence at other tissues. Furthermore, the results observed from a two-flank tumor xenograft model showed that FITC-Rituximab possessed specific binding affinity for CD20-overexpressed lymphoma. CONCLUSION: The in vivo optical imaging system can accurately monitor the distribution of FITC-Rituximab in tumor-bearing nude mice. And this technique has a reference value and significance for a real-time analysis of tumor-targeting capability of antibody drugs.