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During the effector phase of graft- versus-host disease (GvHD) response, donor T cells play an essential role and they are believed to change the expression of activation and co-stimulatory markers associated with functional alloreactivity. We analysed the expression of CD25, CD69, HLA-DR, CD154 and CD134 on CD4+ and CD8+ T cells by flow cytometry during acute GvHD (aGvHD) in 24 patients receiving human leucocyte antigen (HLA)-identical stem cell transplants. Expression of these molecules in nine patients with stages I–IV aGvHD was compared with 15 patients without aGvHD ( n = 15). Serial analysis showed that peripheral blood of aGvHD patients presented a significant increase of CD4+ CD25+ cells ( P < 0·03), CD4+ CD69+ ( P < 0·04) and CD4+ CD134+ cells ( P < 0·01). Additionally, there was a significant increase in CD8+ cells expressing CD134 ( P = 0·007) and CD154 ( P = 0·02). After resolution of aGvHD, the increased expression of these molecules returned to values comparable to patients without aGvHD. Only two of the 15 patients without clinical signs of aGvHD presented activated T cells that could not be attributed to development of aGvHD. In summary, our data show that multiple activation molecules are preferentially up-regulated on CD4+ and CD8+ T cells from patients with aGvHD. These patients had a significant increase in the expression of the co-stimulatory molecules CD134 and CD154. [ABSTRACT FROM AUTHOR]

HnRNP antigen from HeLa cells was purified using a monoclonal antibody (383 IgM) that recognizes heterogeneous nuclear ribonucleoprotein (hnRNP). From extracts of HeLa cells radiolabelled with 32P, this antibody immunoprecipitates relatively large RNAs of heterogeneous size which are synthesized in the presence of actinomycin D at doses which suppress synthesis of ribosomal RNAs (characteristic features of heterogeneous nuclear RNA). In immunoblots, 383 IgM binds to seven polypeptides: one of approximately 23,000 daltons, three between 30.000 and 43,000 daltons which correspond to the known hnRNP polypeptides called Al. A2 and CI, one of approximately 50,000 daltons, and a doublet of approximately 120,000 daltons. These proteins comigrate through sucrose density gradients suggesting that they are physically associated. Thus, 383 IgM appears to define an epitope that is shared among a number of the protein components of hnRNP. This antibody has been used to design a simple and fast protocol which allows the determination of autoantibodies from human sera by ELISA. [ABSTRACT FROM AUTHOR]

The PM/Scl antigen from mammalian cells has been characterized as a nucleolar and nucleoplasmic molecular complex containing at least 16 polypeptides ranging in molecular weight from 110 to 20 kD. Of these polypeptides, we have found those of 68, 39 and 20 kD to be in a phosphorilated form. Whereas the entire complex was precipitated by all the anti-PM/Scl sera tested, in immunoblots the antibodies specifically recognized determinants on the 110-kD protein. This protein was immunoprecipitated more preferentially from nuclcoli extracts than from total cell extracts. Moreover, this protein disappeared from the immunoprecipitates when treated with DNAse. Likewise, the immunoblot reaction of the specific antibodies with the 110-kD protein was abolished by treatment of the extracts with DNAse and trypsin, and was resistant when extracts were treated with RNAse, Affinity-purified antibodies from this protein selectively stained the nucleoli and the nucleoplasm oft he mammalian cells. Moreover, when the cultured cells used in immunofluorescence were treated with DNAse, the affinity purified antibodies from the 110-kD protein gave negative fluorescence, flow ever, when whole anti-PM/Scl sera were used, a nucleolar and nucleoplasmic staining was found. We conclude that the 110-kD protein has at least one of the autoimmunogenic epitopes of the PM/Scl antigen, recognized by all anti-PM/Scl sera tested. Other epitopes differing in their DNAse sensitivity may also be present in the PM/Scl antigen. [ABSTRACT FROM AUTHOR]