Demonstration that IgG memory is carried by IgG‐bearing cells

Abstract

Memory B cells which give rise to JgG antibody‐producing cells were generally assumed to be IgG‐bearing cells. However, recent studies indicating that very few IgG‐bearing cells exist in lymphoid tissue brought this assumption into question. In this study, we examined directly the question whether IgG‐bearing cells contain functional precursors of IgG antibody‐producing cells. Using the adoptive secondary immune response, we demonstrated that Ig‐1b‐bearing cells, isolated with the fluorescence‐activated cell sorter (FACS), are the functional precursors of Ig‐1b‐producing cells. Further, we have enriched IgG₂ and IgG₁ memory B cells using the FACS. The results show that IgG₂‐bearing cells are the functional precursors of the IgG₂ antibody‐producing cells. Likewise, the IgG₁‐bearing cells are the functional precursors of IgG₁ antibody‐producing cells. Thus, IgG memory cells have surface IgG which indicates the class and allotype commitment of the memory cell and its progeny antibody‐forming cells.