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Transcription, translation and secretion of both IgA subclasses in polyclonally activated human lymphocytes
Author(s) -
Islam Khalid Bin,
Hassan Mohammed Sawkat,
Engström Pererik,
Hammarström Lennart,
Edvard Smith C. I.
Publication year - 1990
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.1830200505
Subject(s) - pokeweed mitogen , biology , subclass , microbiology and biotechnology , messenger rna , polyclonal antibodies , flow cytometry , in vitro , stimulation , antibody , gene , peripheral blood mononuclear cell , immunology , endocrinology , biochemistry
Abstract To analyze human IgA subclass‐specific mRNA we have developed RNA probes for quantitation of α1 and α2 heavy chain constant region genes by solution hybridization. Under our assay conditions, we can detect as little as 3 pg of specific mRNA andthere is less than 2% cross‐reactivity between the two IgA subclasses. Using this method, the relative proportions of IgA1 and IgA2 mRNA in pokeweed mitogen(PWM)‐stimulated cells were found to be 66% and 34%, respectively, while in the Epstein‐Barr virus (EBV)‐stimulated cells they were 77% and 23%, respectively. Cytoplasmic staining of the plasma cells and determination of IgA subclass distribution by flow cytometry revealed an almost even distribution of the two IgA subclasses as induced by both activators. The culture supernatant contained 72% IgA1 and 28% IgA2 after PWM stimulation, while EBV stimulation induced 85% IgA1 and 15% IgA2. This report thus describes a method for the quantitative analysis of IgA subclass‐specific mRNA. Furthermore, we present evidence that in response to in vitro stimulation of peripheral blood lymphocytes by polyclonal activators the IgA‐producing B cells not only synthesize both isotypes but also have the potential to secrete them.