ABSTRACT
Neutralizing antibody responses to commercial Japanese-produced chick embryo cell (CEC) vaccines in Japanese and to commercial human diploid cell rabies vaccines (HDCV) in Filipinos were compared by the rapid fluorescent focus inhibition test (RFFIT). Neutralizing antibody titers of the Japanese after subcutaneous (sc) immunization with two doses of the CEC vaccines were not lower than those of the Filipinos with two or three doses of HDCV by intramuscular (i.m.) or intradermal (i.d.) route, respectively. Protein nitrogen content of the CEC vaccine was about 1/300th that of the HDCV. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analysis showed that non-viral protein content in the CEC vaccine was much lower than that in the HDCV. The CEC rabies vaccine seems to be as safe and effective as the HDCV for human pre-exposure immunization.