TY - JOUR
T1 - Alternative splicing of class Ib major histocompatibility complex transcripts in vivo leads to the expression of soluble Qa-2 molecules in murine blood
AU - Tabaczewski, Piotr
AU - Shirwan, Haval
AU - Lewis, Keith
AU - Stroynowski, Iwona
PY - 1994/3/1
Y1 - 1994/3/1
N2 - Class Ib Qa-2 molecules are expressed in tissue culture cells as ≃40-kDa membrane-bound, glycophosphatidylinositol-linked antigens and as ≃39-kDa soluble polypeptides. Recently, alternative splicing events which delete exon 5 from a portion of Qa-2 transcripts were demonstrated to give rise to truncated secreted Qa-2 molecules in transfected cell lines. To determine whether this mechanism operates in vivo and to find out whether Qa-2 can be detected in soluble form in circulation, murine blood samples were analyzed. Critical to these experiments was preparation of an anti-peptide antiserum against an epitope encoded by a junction of exon 4 and exon 6. We find that supernatants of splenocytes cultured in vitro as well as serum or plasma contain two forms of soluble Qa-2 molecules. One form corresponds to a secreted molecule translated from transcripts from which exon 5 has been deleted; the other is derived from membrane-bound antigens or their precursors. The levels of both soluble forms of Qa-2 are inducible upon stimulation of the immune system, suggesting an immunoregulatory role for these molecules or for the mechanism leading to the reduction of cell- associated Qa-2 antigens in vivo.
AB - Class Ib Qa-2 molecules are expressed in tissue culture cells as ≃40-kDa membrane-bound, glycophosphatidylinositol-linked antigens and as ≃39-kDa soluble polypeptides. Recently, alternative splicing events which delete exon 5 from a portion of Qa-2 transcripts were demonstrated to give rise to truncated secreted Qa-2 molecules in transfected cell lines. To determine whether this mechanism operates in vivo and to find out whether Qa-2 can be detected in soluble form in circulation, murine blood samples were analyzed. Critical to these experiments was preparation of an anti-peptide antiserum against an epitope encoded by a junction of exon 4 and exon 6. We find that supernatants of splenocytes cultured in vitro as well as serum or plasma contain two forms of soluble Qa-2 molecules. One form corresponds to a secreted molecule translated from transcripts from which exon 5 has been deleted; the other is derived from membrane-bound antigens or their precursors. The levels of both soluble forms of Qa-2 are inducible upon stimulation of the immune system, suggesting an immunoregulatory role for these molecules or for the mechanism leading to the reduction of cell- associated Qa-2 antigens in vivo.
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U2 - 10.1073/pnas.91.5.1883
DO - 10.1073/pnas.91.5.1883
M3 - Article
C2 - 8127900
AN - SCOPUS:0028343567
SN - 0027-8424
VL - 91
SP - 1883
EP - 1887
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 5
ER -