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# Pokeweed Mitogen Inhibition of Protein Synthesis in Cultured Lymphoblastoid Lines

Richard A. Polin and Roger Kennett
In Vitro
Vol. 16, No. 7 (Jul., 1980), pp. 575-580
Stable URL: http://www.jstor.org/stable/4292383
Page Count: 6
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## Abstract

Pokeweed mitogen (PWM) and ricin are both lectins derived from plant seeds. They are glycoproteins and share the ability to agglutinate a variety of animal cells including erythrocytes. The effect of these two lectins on protein synthesis was studied in four long-term lymphoblastoid lines (8866 and GM1531, which are B cell lines; and CCRF/CEM and MOLT 4, which are T-cell lines). Ricin ($50 \mu g/ml$) completely inhibited protein synthesis by 2 hr in both B-cell and T-cell lines as measured by the uptake to $[^3H]leucine$. The PWM appeared more specific and at a concentration of $500 \mu g/ml$ inhibited protein synthesis only in B-cell lines (8866 and GM1531). This effect was maximal at 5 hr. To investigate the reason for the differential effect of PWM on T and B cells, 125I-labeled PWM was incubated with 8866, MOLT 4, and CCRF/CEM to see if a significant difference in binding to B cells and T cells could be demonstrated. It does not appear that the differential effect on T and B cells is due to a difference in the amount of PWM bound. On the other hand it is possible that the B cells may bind some toxic subcomponent of the PWM preparation that the T cells do not bind because of a difference in composition or arrangement of cell surface glycoproteins.

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