マウス抗体クラススィッチ過程の速度論に基づく解析

Abstract

The class-switching process of immunoglobulin(Ig) gene-transcribing cells was investigated in the thymus of BALB/c female mice. The ratios of IgM,IgG1,IgG3 and IgE-transcripts were determined with aging by realtime PCR. Logarithmic values of IgG1/1gM and IgG3/IgM increased rapidly from birth to several weeks and then gradually. While that of IgE/IgM increased similarly to about 7.5 weeks and it decreased afterwards. Rate theory was applied to analyze these results with supposing both that transcript-quantity was proportional to the number of transcribing cells and that IgM-transcribing cells were supplied continually from stem cells in vivo. On the first order differential concurrent model, in which IgM cells recombined Ig genes and changed to other Ig class-transcribing with rate constants k, the rate equations were solved theoretically. The calculated values of logIgGl/IgM and logIgG3/IgM were good agreement with experimental ones for periods up to 400 days after birth. But, in the case of logIgE/IgM, which had a maximum, this theory could not agree the maximum value

マウス胸腺での抗体遺伝子の転写量比の経時変化を測定し,胸腺でも抗体のクラススィッチ過程が起きていることを示唆した。また,クラススィッチ過程の細胞分化を一次並行反応とみなすことにより,測定結果を速度論で解析する方法を示した。ただし,IgEの結果に関しては,濃度項が分化反応の駆動力である反応速度論では説明できず,他の因子を考慮した方法論が必要であることが判明した。