Diff. between Rag mice and SCID mice - (Aug/06/2007 )

Hi all,

I was doing some reading on the RAG and SCID mice, but I don't know the main difference between the two. Both mutations affect the mice ability to make fully functional T cells and B cells. Some say that mutations in RAG gene leads to SCID condition, which confuses me even further. Some say SCID mice have no T or B cells, which puts me under the impression that RAG mice somehow have T and B cells, just not the appropriate receptors. Can anyone clear this up for me please? Thank you very much.

I think the basic difference between SCID and RAG knockout mice is that SCID mice were developed by in-breeding and RAG knockout was a targeted mutation. Both can't rearrange immunoblobulin (this in turn means there is no B-cell receptor) or T-cell receptor and functional B- and T-cells require these receptor signals for survival during their development from haemapoeitic progenitors. According to a link I found there can be leakiness i.e. you may have low numbers of functional B- and T-cells.