Reversal of the CD4(+)/CD8(+) T-cell ratio in lymph node cells upon in vitro mitogenic stimulation by highly purified, water-soluble S3-S4 dimer of pertussis toxin.
Pertussis toxin (PT), a holomer consisting of a catalytic S1 subunit and a B oligomer composed of S2-S4 and S3-S4 dimers, held together by the S5 subunit, exerts profound effects on immune cells, including T-cell mitogenicity. While the mitogenic activity of PT was shown to reside fully within the B oligomer, it could not be assigned to any particular B-oligomer component. In this study, we purified the S3-S4 dimer to homogeneity under conditions propitious to maintenance of the native conformation. In contrast to previous reports which suggested that both S3-S4 and S2-S4 dimers are necessary for mitogenic activity, our preparation of the highly purified S3-S4 dimer was as strongly mitogenic as the B oligomer, suggesting that the S3-S4 dimer accounts for the mitogenic activity of the B oligomer. Moreover, in vitro stimulation of naive lymphocytes by the S3-S4 dimer resulted in reversal of the normal CD4(+)/CD8(+) T-cell ratio from approximately 2:1 to 1:2. The reversal of the CD4(+)/CD8(+) T-cell ratio is unlikely to be due to preferential apoptosis-necrosis of CD4(+) T cells, as indicated by fluorescence-activated cell sorter analysis of annexin-stained T-cell subsets, or to preferential stimulation of CD8(+) T cells. The mechanism underlying the reversal requires further investigation. Nevertheless, the data presented indicate that the S3-S4 dimer may have potential use in the context of diseases amenable to immunological modulation.
Latif
R
R
Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel.
Kerlero de Rosbo
N
N
Amarant
T
T
Rappuoli
R
R
Sappler
G
G
Ben-Nun
A
A
D000818:Animals; D015153:Blotting, Western; D016516:CD4-CD8 Ratio; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D019281:Dimerization; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008934:Mitogens / Q000494:pharmacology*; D037342:Pertussis Toxin; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
D008934:Mitogens; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D010566:Virulence Factors, Bordetella; C083389:pertussis toxin, S4 subunit; D037342:Pertussis Toxin