Phosphocholine （PC） is the immunodominant epitope found on the surface of a number of microorganisms, including Streptococcus pneumoniae （SPn）, and is thought to play a vital role in the pathogenesis of SPn. B cel...Phosphocholine （PC） is the immunodominant epitope found on the surface of a number of microorganisms, including Streptococcus pneumoniae （SPn）, and is thought to play a vital role in the pathogenesis of SPn. B cells expressing M 167Hκ24L immunoglobulin receptors specific for PC have been shown to be autoreactive in that they undergo clonal deletion in both X-linked immune-deficient and Rag-/- mice. We have now shown that B cells expressing M603HK8L PC-specific receptors also delete in Rag-/- mice, whereas those expressing T15HK22L transgenes do not delete. However, T15HK22L B cells are lost in normal heterozygous transgenic mice because they cannot compete with normal B cells. These data indicate that M167Hκ24L and M603H^8L PC-specific B cells are recognizing an autoantigen expressed on membranes which causes them to downregulate their receptors and clonally delete, while T15Hκ22L B cells are tolerized by a soluble form of PC-antigen which results in their being trapped in the spleen. Thus, the types of tolerance seen in autoreactive PC-specific B cells are dependent on the idiotype of the receptors expressed.展开更多
文摘Phosphocholine （PC） is the immunodominant epitope found on the surface of a number of microorganisms, including Streptococcus pneumoniae （SPn）, and is thought to play a vital role in the pathogenesis of SPn. B cells expressing M 167Hκ24L immunoglobulin receptors specific for PC have been shown to be autoreactive in that they undergo clonal deletion in both X-linked immune-deficient and Rag-/- mice. We have now shown that B cells expressing M603HK8L PC-specific receptors also delete in Rag-/- mice, whereas those expressing T15HK22L transgenes do not delete. However, T15HK22L B cells are lost in normal heterozygous transgenic mice because they cannot compete with normal B cells. These data indicate that M167Hκ24L and M603H^8L PC-specific B cells are recognizing an autoantigen expressed on membranes which causes them to downregulate their receptors and clonally delete, while T15Hκ22L B cells are tolerized by a soluble form of PC-antigen which results in their being trapped in the spleen. Thus, the types of tolerance seen in autoreactive PC-specific B cells are dependent on the idiotype of the receptors expressed.
