Regulation of an anti-polysaccharide immune response in BALB/c mice through a tight T and B lymphocyte idiotypic connection.

The isotype expression in the J558 idiotype-associated humoral immune response against alpha(1-->3)-dextran in BALB/c mice is controlled by idiotype-specific T cells which silence in situ B lymphocytes primed and committed to an IgG response. This leads to a restriction of the type II thymus-independent response to the sole production of IgM antibodies. The availability of the T cell receptor (TcR) alpha and beta sequences for such a regulatory T cell clone allows the investigation of the degree of heterogeneity of the TcR usage of these T cells. It is found that all alpha(1-->3)-dextran-primed BALB/c mice use a very similar, possibly identical TcR. This suggests a tight, possibly genetically programmed, interaction between the J558 idiotype-bearing dextran-specific B cells and their idiotype-specific regulatory T cell counterparts.