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Evidence that Pokeweed‐Mitogen‐reactive B Cells are Pre‐committed in Vivo to the High‐rate Secretion of a Single Immunoglobulin Isotype in Vitro
Author(s) -
STEVENS R. H.,
MACY E.,
THIELE C. J.
Publication year - 1981
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1981.tb00587.x
Subject(s) - isotype , pokeweed mitogen , antibody , toxoid , biology , immunoglobulin class switching , b cell , immunoglobulin g , immunoglobulin m , secretion , microbiology and biotechnology , in vivo , immunology , in vitro , peripheral blood mononuclear cell , endocrinology , immunization , monoclonal antibody , biochemistry
Normal human peripheral blood B cells that respond to pokeweed mitogen (PWM)‐activated irradiated T cells with high‐rate immunoglobulin secretion in vitro were analysed with respect to the frequency of the cells stimulated to high‐rate immunoglobulin secretion in vitro and whether the progeny of each cell had the potential to secrete one or multiple immunoglobulin isotypes. In vitro cultures containing limiting numbers of human B cells were initiated in the presence of PWM and excess irradiated T cells, and the quantity of IgM, IgG and IgA secreted was determined after 9 days. The level of immunoglobulin secretion per cell in limiting‐dilution microcultures was shown to be equivalent to that seen in the routinely used macrocultures, indicating that major loss of B‐cell function was not occurring in the microcultures. At limiting B‐cell numbers, individual microcultures were often shown to produce immunoglobulin of a single isotype, either IgM, IgG or IgA. Cultures that did produce multiple immunoglobulin isotypes occurred with a frequency predicted by the random distribution of B cells committed to production of a single isotype. A similar independent distribution of IgM anti‐tetanus toxoid and IgG anti‐tetanus toxoid antibody‐producing precursors was observed when B cells selected on the basis of surface IgM were used in the microcultures. These results suggest that PWM‐reactive B cells are at a stage of maturation in vivo such that they have the potential to secrete a single immunoglobulin isotype when activated in vitro.