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Biomedical subjects

L Gyenes

Publications and source records attributed to L Gyenes.

At least 19 recordsLinked to original sources
PubMed1980

A semi-automated rapid and sensitive microcytotoxicity assay for antibody-mediated cytolysis.

This technique used a Coulter counter to enumerate the target cells remaining after partial lysis with antibody and complement, followed by the destruction of the lysed cells with pronase. Results obtained by this method are compared with those from conventional dye exclusion tests where the final enzymatic step is omitted. Comparisons were made with an anti-Thy-1.2 serum, a monoclonal anti-Thy-1.2 preparation and an anti-H-2k serum. In all cases the semi-automated test gave better results than the dye exclusion test and proved to be highly sensitive and reproducible.

Animals↗
PubMed1976

The effect of neuraminidase on the sensitivity of tumor cells toward lysis by antibody and complement or by sensitized lymphocytes.

The effect of neuraminidase treatment on the antigenicity of sarcoma I (Sal) and mastocytoma P-815-X2 cells was compared, both in terms of their reaction with various antisera (C57BL/6 anti-SaI, C57BL/6 anti-mastocytoma, rabbit and horse ALS) and complements (guinea pig, rabbit) or with sensitized lymphocytes (C57BL/6 anti-SaI, C57BL/6 anti-mastocytoma, A anti-mastocytoma). With sensitized lymphocytes the reactivity of neuraminidase-treated tumor cells was similar to that of nontreated cells. In contrast, after neuraminidase treatment, the tumor cells showed increased specific lysis with the antisera and complement. Rabbit complement was highly cytotoxic to the neuraminidase-treated cells but this nonspecific activity could be removed by absorption with agar or agarose. The results of this study would strongly suggest that neuraminidase treatment does not change the antigenic determinants of tumor cells but increases their interaction with complement after removal of negatively charged sialic acids.

Animals↗
PubMed1975

Isolation of rapidly labeled RNA from mouse L-cells using cupric sulfate.

Cultured mouse L-cells, pulse labeled for 5 min with 3H-uridine, were gently suspended in 0.5mM cupric sulfate and 0.5% sodium dodecyl sulfate at 4 degrees C and treated with cold phenol. Only the RNA, containing less than 1% DNA, was extracted by this procedure. The rapidly labeled ribosomal RNA precursors (44S, 34S) and cytoplasmic 8S RNA showed specific activities higher than that of tRNA and were present in the RNA fraction insoluble in 2M NaCl.

Animals↗
PubMed1975

Differences in the sensitivity of tumor cells and normal lymphocytes toward lysis by alloantibodies and guinea pig or rabbit complement.

Antisera produced against sarcoma I (SaI) cells in C57BL/6 and CBA mice tested for their cytotoxic activity against normal A lymphocytes and SaI tumor cells, using guinea pig or rabbit complement. Whereas high levels of cytotoxic activity against normal A lymphocytes were revealed with both antisera using either complement, only rabbit complement produced significant lysis of tumor cells under the standard conditions of the cytotoxic test (30 min, 37 C). However, upon prolonged incubation, guinea pig complement also produced high levels of lysis of SaI cells with the C57BL anti-SaI, but not with the CBA anti-SaI serum. Because these two antisera contain antibodies directed mainly against the H-2K and H-2D specificities, respectively, these results seemed to suggest that SaI cells are lysed in the presence of guinea pig complement with anti-H-2K antibodies but not with anti-H-2D antibodies. This conclusion was further supported by the use of antisera of restricted specificity prepared by selective absorption of the C57BL anti-SaI serum with CBA or DBA/2 cells. However, a C57BL anti-A serum which did not contain antibodies capable of lysing SaI target cells on prolonged incubation with guinea pig complement did not inhibit their subsequent lysis with the C57BL anti-SaI serum. These findings might suggest that under these modified conditions, mainly tumor-specific antigen-antibody systems are revealed with guinea pig complement, whereas with rabbit complement, under the standard conditions of the cytotoxic test, all antigen-antibody systems are detected.

Absorption↗