Abstract
The effect of phytohemagglutinin (PHA) on the ability of human lymphocytes to transport the nonutilizable amino acid, α-aminoisobutyric acid (AIB) has been studied. PHA binds rapidly to plasma membrane receptor sites with half maximal binding requiring approximately 7.5 min. During the first 30 min after PHA addition to lymphocytes no change was detected in AIB transport, but then a linear increase in the initial rate of AIB transport occurred over the next 9 hr. Subsequently, the rate of AIB transport stabilized at a level 6-7 times greater than that found in control lymphocytes. The change in membrane function developed even when de novo protein synthesis was inhibited by 85-90% with puromycin or cycloheximide. However, the PHA effect did not occur when the lymphocytes were maintained at 4°C.
Studies of the kinetics of AIB uptake by control and PHA-treated lymphocytes demonstrated that PHA increases the Vmax of AIB uptake by 6-7-fold (0.7 mμmole AIB per 106 lymphocytes/15 min versus 0.1 mμmole per 106 lymphocytes/15 min) without affecting the Km (Michaelis constant) of the transport system (2mM in both cases).
When fetuin was added to lymphocyte cultures to remove bound PHA, the PHA-induced increase in the rate of AIB uptake was arrested at the rate achieved during the time of prior incubation with PHA. This level of AIB transport persisted for at least 3 hr after 80% of the PHA was removed from the cell membrane.
These data demonstrate that PHA rapidly induces a change in a lymphocyte cell membrane transport function, and that the continued presence of PHA on the cell membrane is required for the full stimulatory effect to be reached. The data do not distinguish between a direct action of PHA upon the lymphocyte membrane or the possibility that PHA slowly enters into the cell where it then exerts its effect.
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Selected References
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- EAGLE H. Amino acid metabolism in mammalian cell cultures. Science. 1959 Aug 21;130(3373):432–437. doi: 10.1126/science.130.3373.432. [DOI] [PubMed] [Google Scholar]
- Fisher D. B., Mueller G. C. An early alteration in the phospholipid metabolism of lymphocytes by phytohemagglutinin. Proc Natl Acad Sci U S A. 1968 Aug;60(4):1396–1402. doi: 10.1073/pnas.60.4.1396. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Foster D. O., Pardee A. B. Transport of amino acids by confluent and nonconfluent 3T3 and polyoma virus-transformed 3T3 cells growing on glass cover slips. J Biol Chem. 1969 May 25;244(10):2675–2681. [PubMed] [Google Scholar]
- GREENWALT T. J., GAJEWSKI M., McKENNA J. L. A new method for preparing buffy coat-poor blood. Transfusion. 1962 Jul-Aug;2:221–229. doi: 10.1111/j.1537-2995.1962.tb00228.x. [DOI] [PubMed] [Google Scholar]
- HELMREICH E., KIPNIS D. M. Amino acid transport in lymph node cells. J Biol Chem. 1962 Aug;237:2582–2589. [PubMed] [Google Scholar]
- Hausen P., Stein H. On the synthesis of RNA in lymphocytes stimulated by phytohemagglutinin. 1. Induction of uridine-kinase and the conversion of uridine to UTP. Eur J Biochem. 1968 Apr;4(3):401–406. doi: 10.1111/j.1432-1033.1968.tb00226.x. [DOI] [PubMed] [Google Scholar]
- Hirschhorn R., Brittinger G., Hirschhorn K., Weissmann G. Studies on lysosomes. XII. Redistribution of acid hydrolases in human lymphocytes stimulated by phytohemagglutinin. J Cell Biol. 1968 May;37(2):412–423. doi: 10.1083/jcb.37.2.412. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kornfeld R., Kornfeld S. The structure of a phytohemagglutinin receptor site from human erythrocytes. J Biol Chem. 1970 May 25;245(10):2536–2545. [PubMed] [Google Scholar]
- Kornfeld S. Decreased phytohemagglutinin receptor sites in chronic lymphocytic leukemia. Biochim Biophys Acta. 1969 Dec 30;192(3):542–545. doi: 10.1016/0304-4165(69)90409-7. [DOI] [PubMed] [Google Scholar]
- Lucas Z. J. Pyrimidine nucleotide synthesis: regulatory control during transformation of lymphocytes in vitro. Science. 1967 Jun 2;156(3779):1237–1240. doi: 10.1126/science.156.3779.1237. [DOI] [PubMed] [Google Scholar]
- MICHALOWSKI A., JASINSKA J., BROZOSKA W. J., NOWOSLAWSKI A. CELLULAR LOCALIZATION OF THE MITOGENIC PRINCIPLE OF PHYTOHAEMAGGLUTININ IN LEUCOCYTE CULTURES. Exp Cell Res. 1964 Apr;34:417–419. doi: 10.1016/0014-4827(64)90380-5. [DOI] [PubMed] [Google Scholar]
- NOALL M. W., RIGGS T. R., WALKER L. M., CHRISTENSEN H. N. Endocrine control of amino acid transfer; distribution of an unmetabolizable amino acid. Science. 1957 Nov 15;126(3281):1002–1005. doi: 10.1126/science.126.3281.1002. [DOI] [PubMed] [Google Scholar]
- Perper R. J., Zee T. W., Mickelson M. M. Purification of lymphocytes and platelets by gradient centrifugation. J Lab Clin Med. 1968 Nov;72(5):842–848. [PubMed] [Google Scholar]
- Pogo B. G., Allfrey V. G., Mirsky A. E. RNA synthesis and histone acetylation during the course of gene activation in lymphocytes. Proc Natl Acad Sci U S A. 1966 Apr;55(4):805–812. doi: 10.1073/pnas.55.4.805. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBERG L. E., BLAIR A., SEGAL S. Transport of amino acids by slices of rat-kidney cortex. Biochim Biophys Acta. 1961 Dec 23;54:479–488. doi: 10.1016/0006-3002(61)90088-9. [DOI] [PubMed] [Google Scholar]
- Razavi L. Cytoplasmic localization of phytohaemagglutinin in peripheral white cells. Nature. 1966 Apr 23;210(5034):444–445. doi: 10.1038/210444b0. [DOI] [PubMed] [Google Scholar]
- Robineaux R., Bona C., Anteunis A., Orme-Rosselli L. La capacité endocytaire des lymphocytes ganglionnaires du cobaye, normaux et ransformés in vitro. Ann Inst Pasteur (Paris) 1969 Dec;117(6):790–795. [PubMed] [Google Scholar]
- SKOOG W. A., BECK W. S. Studies on the fibrinogen, dextran and phytohemagglutinin methods of isolating leukocytes. Blood. 1956 May;11(5):436–454. [PubMed] [Google Scholar]
- Weber T., Nordman C. T., Gräsbeck R. Separation of lymphocyte-stimulating and agglutinating activities in phytohaemagglutinin (PHA) from Phaseolus vulgaris. Scand J Haematol. 1967;4(1):77–80. doi: 10.1111/j.1600-0609.1967.tb01601.x. [DOI] [PubMed] [Google Scholar]
