The suppression of an amber mutation in a permissive strain of Escherichia coli can be achieved by a new tRNA species, a suppressor tRNA (for a review, see Reference 1). The tyrosine amber suppressor tRNA arises from a redundant tRNA species in the Sustrain by a single base change in the anticodon (2). However, this may not be the only mechanism to generate suppressor tRNA species, as suggested...

The marine bacterium Vibrio alginolyticus has a single polar flagellum. Formation of that flagellum is regulated positively and negatively by FlhF and by FlhG, respectively. The ΔflhF mutant makes no flagellum, whereas the ΔflhFG double-deletion mutant usually lacks a flagellum. However, the ΔflhFG mutant occasionally reverts to become motile by forming peritrichous flagella. We have isolated a...

The growth of two-tone rate suppression with suppressor level was studied for auditory-nerve fibers in anesthetized cats. The level of a tone at the characteristic frequency (CF) was adjusted by an adaptive procedure (PEST) so that, when presented with a suppressor tone, the CF tone would produce a criterion discharge rate. Suppression (in dB) was defined as the CF-tone level that met criterion...

Previous studies have shown that melanoma patients develop an immune response to cell surface melanoma-associated antigens. The presence of this antibody response to cell surface antigens has been correlated with a better clinical outcome when melanoma patients are treated with an allogeneic melanoma cell vaccine (MCV) as an active immunotherapy protocol. It was hypothesized that the inability ...

The complex regulatory interactions among T lymphocytes initiating, amplifying, and suppressing various effector-immune reactions have recently become the subject of intense investigation. We recently reported on a T cell participating in suppressing the delayed-type hypersensitivity (DTH) 1 response to the haptenic determinant 4hydroxy-3-nitrophenyl acetyl (NP) (1). We now report on a second p...

The presence of H-2 gene products on mixed leukocyte reaction (MLR) supressor factor was investigated by passage of MLR-suppressor factor (SF) over solid immunoadsorbents prepared with various anti-H-2 subregion sera. Antisera with specificity for all or certain I subregion determinants removed or significantly reduced suppressor activity; adsorption was not consistent with K or D region specif...

OBJECTIVE It has been shown that SOCS-1 plays an important role in the proper control of cytokine/growth factor responses and acts as a tumor suppressor in acute myeloid leukemias. Therefore, the objective of the present study was to evaluate the in vitro effect of treatment with Nutlin-3, a small molecule inhibitor of the MDM2/p53 interaction, on the expression of the suppressor of cytokine si...

Spleen cells from mice with syngeneic tumor transplants are hyporesponsive in mixed-lymphocyte culture. The hyporesponsiveness is due to the activation of suppressor cells. Spleen from tumor-bearing mice, treated with mitomycin and added to normal mixed lymphocyte culture (with responding cells syngeneic to the added cells), inhibits proliferation of the responding cells. Suppressor activity in...

The suppression of an amber mutation in a permissive strain of Escherichia coli can be achieved by a new tRNA species, a suppressor tRNA (for a review, see Reference 1). The tyrosine amber suppressor tRNA arises from a redundant tRNA species in the Sustrain by a single base change in the anticodon (2). However, this may not be the only mechanism to generate suppressor tRNA species, as suggested...

The estimate of the frequency of suppressor T lymphocytes in unfractionated cell populations remains challenging, mainly because these regulatory cells do not display specific immunophenotypic markers. In this paper, we describe a novel theoretical approach for quantifying the frequency of suppressor cells. This method is based on limiting dilution data modeling, and allows the simultaneous est...