Redistribution Of FcRn In The Main Organs Of Neonatal And Pubertal Rats And Its Pharmaceutic Value Evaluation

FcRn was first identified in the rat intestine epithelial cells as a member of the majorhistocompatibility complex (MHC) class I family. FcRn has been widely studied for itsmediating of protection to the neonatal. Recently, FcRn has been identified as the “IgG andalbumin protection” receptor, which mediates the trans membrane transportation of IgG andalbumin, to prolong the half-lives of these two proteins. This study analyzed the distributionof FcRn in the principal organs of neonatal and pubertal rats; meanwhile, the regulation roleof FcRn to IgG/albumin had also been studied in vivo. The results provide information on thedistribution of FcRn in rats’ main organs and also on the evaluation of FcRn’s pharmaceuticalvalue. This study is divided into two parts:1. The characterization of the expression of FcRn in different organs of neonatal andpubertal rats by reverse transcription-PCR (RT-PCR) and immunohistochemistry. It wasdemonstrated that FcRn is expressed in lungs, skin, livers, heart, kidneys, skeleton muscles,intestines and spleens with varying levels post-gestation from d1to d63. FcRn’s expressionin most organs hold a higher fluctuation before the weaning, while the expression decreasedsignificantly after the weaning. Lungs were the predominant organs for FcRn expression,whereas skin, liver and intestine are considerably less expressed organs.2. The determination of half-lives of exogenous IgG and albumin, the serumconcentration of endogenous IgG and albumin. It was demonstrated that with co-injection ofIgG and albumin, the half-life of IgG is12.45h, the difference is not significant compared tothe single injection of IgG (12.4h); while with co-injection fo IgG and albumin, the half-lifeof albumin increased by3hs, from13.75h to16.5h. Meanwhile, exogenous IgG raised thealbumin level in serum. This study enables a better understanding on the function of FcRn in vivo, which helpsus to depen our knowledge in the mechanism of FcRn mediated reactions in vivo. The data inthis study could provide the theoretical foundation for the treatment of autoimmue disease, themodification and designing of antibody drugs, the amplication of small molecular peptides.Meanwhile, the analysis of these data also provides clues for the regulation of IgG andalbumin in vivo.