Mice Fc¦Á / ¦Ìr Histological Positioning Preliminary Study

Fcα/μR is a newly found Fc receptor specifically for IgA and IgM.Its mRNA is expressed on several tissues in normal mouse.It was found that Fcα/μR was involved in the endocytosis of immune complexes by B cell.However,the biology function of Fcα/μR is still largely unknown at present,pIgR is also a receptor for IgA and IgM,which transcytose pIgA and pIgM cross epithelial cells,so it is an important protein in mucosal immunity. The gene location of Fcα/μR is near to pIgR on mouse and human chromosome 1,and they have high amino acid homology.In this work,we analyzed the difference between Fcα/μR and pIgR in gene expression and protein distribution,in order to explore functions of Fcα/μR.First we prepared rat monoclone and polyclone antibodies against mouse Fcα/μR (mFcα/μR) and mouse pIgR(mpIgR).mFcα/μR and pIgR were expressed in E.coli and used as immunogen.Using ELISA,Western blot,FACS and immunocytochemistry,some mAbs was selected.We also identified the specificity of polyclone antibodies.We detected mRNA expression of mFcα/μR and mpIgR in several tissues of normal mice. The results showed that mpIgR was not expressed as widely as mFcα/μR,which was found in liver,heart,spleen,lung,kidney,small intestine,large intestine,thymus,testicle,uterus and ovary.However,immunohistochemistry analysis showed that mFcα/μR was negative in all tissues tested.On the other hand,the mpIgR was found in many organs.So we speculate that mFcα/μR may have similar function with mpIgR,mpIgR was the main receptor when the body is under normal conditions.When mpIgR can't function properly, for example in pIgR knockout mouse or J chain knockout mouse,mFcα/μR may be expressed more and functions as mpIgR.More experiments are needed to support the hypothesis.At the same time,we also detected mRNA expression of rat Fcα/μR.The result showed that rFcα/μR was expressed more widely than rpIgR and rCD89.However,we also got negative result when we detected the protein expression of rFcα/μR using a mouse mAb (anti-hFcα/μR).Although this is in agreement with mFcα/μR result,we still can not make a conclusion about rFcα/μR because of the uncertainty of the mAb's specificity. Based on the above experiments and analysis,this work has provided a useful tool and some data for the study of mFcα/μR,and more work will be carried out in the future research.