Effect of phytohaemagglutinin on CD45 in T cells

Eva Monostori, Zsolt Hartyani, Imre Ocsovszky, Zoltan Hegedus, Tamas Oravecz, Miklos Kalman, Istvan Ando

Research output: Contribution to journalArticle

7 Citations (Scopus)


In this study the effect of PHA activation on the phosphatase activity of CD45 has been investigated in human leukemic T-cell lines. It has been found that in vivo activation of the cells with PHA resulted in 2-4-fold increase in enzyme activity. Addition of PHA to the postnuclear supernatant of cell lysates also resulted in elevation of phosphatase activity. Elevation of enzyme activity resulted from an increase in the amount of antigen in the immunoprecipitates. Elevation of the quantity was not the result of a de novo protein synthesis since the presence of cycloheximide, a protein synthesis inhibitor, did not modulate the effect of PHA. The effect of PHA was specific since ConA, that also bound to the CD45 molecules, or crosslinking of the antigen by antibody did not affect CD45. Since direct binding of PHA to CD45 molecules was shown in immunoblotting analysis, we suggest that the effect of PHA is a consequence of a PHA-induced conformational change of CD45 that results in up-regulation of the analyzed CD45 epitopes.

Original languageEnglish
Pages (from-to)197-201
Number of pages5
JournalImmunology letters
Issue number3
Publication statusPublished - Oct 1994


  • CD45
  • Epitope up-regulation
  • PHA stimulation
  • Phosphatase activity

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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