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Biomedical subjects

P Ivanyi

Publications and source records attributed to P Ivanyi.

70 records · Page 4Linked to original sources
PubMed1979

A syngeneic anti tumor serum recognizing a complex H-2 alloantigen.

A methylcholanthrene induced tumor of BALBc (H-2d) origin had a high rate of spontaneous regression when transplanted into syngeneic animals. The tumor induced in BALB/c mice iso-antibodies with high anti-tumor cytotoxic activity. A specificity analysis of such BALB/c anti MCG4 sera revealed that the antibodies were directed against a tumor antigen which is very similar to H-2- alloantigens (e.g. H-2.5) expressed on normal cells of certain foreign mouse strains. The sera also reacted with nine out of ten B10.W congenic strains bearing H-2wi haplotypes derived from wild mice. Whether the tumor antigen is identical with foreign H-2 antigens or only cross-reactive cannot be decided at present.

Animals↗
PubMed1976

HL-A antigens in juvenile rheumatoid arthritis.

HL-A antigens were examined in sixty-two patients, thirty-one boys and thirty-one girls, diagnosed as having JRA. HL-A 27 was the only antigen with a significantly increased frequency. This increase concerned predominantly male patients in whom the disease developed at the beginning of puberty. In this group of sixteen boys, the polyarticular form was more frequent and tended to be associated with sacroliitis, while the rheumatoid factor was negative in all but one. The frequency of HL-A 27 in this group was 65.5%. The patients were also examined by the lymphotoxic test with anti H-2 alloimmune sera known to exhibit a high degree of association with some HL-A antigens. On JRA lymphocytes these associations were confirmed for HL-A 2 and anti-H-2f and for HL-A 27 and anti-H-2p. The strongest reactions were observed with lymphocytes from male patients around the age of puberty. These data indicate that steroid hormones influence the expressivity of some HL-A associated cell plasma membrane structures.

Adolescent↗
PubMedDate not supplied

HLA-restricted recognition of viral antigens in HLA transgenic mice.

Cytotoxic T lymphocytes (CTL) recognize antigen in the context of the class-I products of the major histocompatibility complex (MHC). The extensive polymorphism of class-I molecules is thought to be linked to their capacity to present a large variety of foreign antigens. Whether a single T-cell receptor (TCR) recognizes two separate epitopes (the foreign antigen and an epitope on MHC molecules), or a single epitope resulting from the combination of a foreign antigen and an MHC molecule, has not yet been resolved. In view of the differences between species in primary structure of histocompatibility antigens, it might be predicted that the TCR repertoire would evolve in concert with the diversity of MHC antigens. The mouse and human TCR repertoire would be optimally adapted to engage in productive interactions only with mouse (H-2) and human (HLA) MHC antigens respectively, especially if the more conserved features of histocompatibility antigens, in addition to foreign antigen, were seen by the TCR. Alternatively, only the most variable segments of MHC antigens might be engaged in antigen presentation and thus in interaction with the TCR. In that case, interaction between MHC plus antigen and the TCR might not necessarily be limited by species-specific features. By analysis of the T-cell response against virus-infected cells in HLA-B27/human beta 2-microglobulin double transgenic mice, we report here that the mouse T-cell repertoire is perfectly capable of using the human HLA-B27 antigen as a restriction element.

Animals↗
PubMedDate not supplied

Anti-MHC immunity detected prior to intentional alloimmunization. IV. Natural monoclonal H-2-specific antibodies.

Naturally occurring H-2-specific antibodies can be detected rather frequently in sera of non-alloimmunized mice by sufficiently sensitive techniques (Cerny-Provaznik et al., 1985a; Cerny-Provaznik & Ivanyi, 1985). In this report, we summarize our experiences with the preparation of monoclonal anit-H-2 antibodies obtained from hybridization experiments from non-alloimmunized mice. From a total of 30 spleen cell hybridization experiments, we could isolate only four anti-H-2 monoclonal antibodies (mAB). Two of the mAB are described in this report. Monoclonal antibody By-2 is anti-Kf and mAB By-3 is anti-Db, Ds. We investigated which conditions favour the isolation of monoclonal H-2-specific antibodies from non-alloimmunized mice. The presence of naturally occurring serum antibodies, the age of the spleen donor mouse or non-specific B cell stimulation were not critical for the isolation of natural anti-H-2 mAB. We hypothesise that the 'natural' H-2-specific antibodies represent compartments of the B cell repertoire which were triggered by modified or aberrant self-MHC expression.

Animals↗