IgM-IgG switch-over among antibody-forming cells in the mouse

摘要: DIFFERENTIATION of immunocytes from stem cells to antibody secreting B involves sequential expression genes coding for heavy chain constant regions. This differentiation seems be independent thymus activity and antigen stimulation, nude mice1 15-week human foetuses2 as well germ-free mice3 piglets4 have proportions surface IgM, IgG or IgA bearing similar those found in normal adults. It has therefore been suggested that the switch-over IgM occurs before contact which leads small lymphocytes plasma cells5. But during production after antigenic stimulation a proportion (1–3%) mouse plaque-forming (PFC) secrete both (refs 6, 7) clones derived single antigen-stimulated precursor antibody8. These observations indicate IgM→IgG switch could driven. We investigated two alternatives by culturing individual PFC mice immunised with sheep erythrocytes (SRBC) study whether daughter produce same different Ig class. part producing parental can generate ‘in vitro’ daughters, but this only first 3 d immunisation.