title: In vitro T cell unresponsiveness following low-dose injection of anti-CD3 MoAb.
abstract: Anti-CD3 MoAb treatment is widely used as an immunosuppressive therapy. In the present study we examined the in vitro T cell response in mice having received 24 h before a single i.v. injection of 10 microgram of anti-CD3 MoAb. We found that splenocytes from these mice displayed a dramatically decreased proliferative response to the T cell mitogens concanavalin A (Con A), anti-CD3, phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) + calcium ionophore, while the effect of lipopolysaccharide (LPS) was not impaired. T cell suppression persisted for about 10 days after anti-CD3 injection, returning to normal within 15 days. The F(ab')2 fragment of anti-CD3 had no such effect, indicating the requirement for in vivo activation. At the dose used, anti-CD3 resulted neither in T cell depletion nor in down-modulation of the CD3/T cell receptor (TCR) complex. The low proliferation was also not explained by apoptosis, following secondary challenge with Con A. Splenocytes from anti-CD3-injected mice were highly responsive to IL-2, but generated little or no IL-2, IL-3, IL-4 and interferon-gamma (IFN-gamma) when exposed to Con A. Normal cytokine production could not be restored by the addition of optimal doses of IL-2 during Con A stimulation. Transforming growth factor-beta (TGF-beta) was the only cytokine whose mRNA expression was not modified in stimulated splenocytes from anti-CD3-injected mice. Furthermore, anti-TGF-beta antibodies increased Con A-induced T cell proliferation, but not cytokine production.
authors.affiliation: Université René Descartes-Paris V, France.
authors.forename: A
authors.initials: A
authors.lastname: Ben-Amor
authors.forename: M C
authors.initials: MC
authors.lastname: Leite-De-Moraes
authors.forename: F
authors.initials: F
authors.lastname: Lepault
authors.forename: E
authors.initials: E
authors.lastname: Schneider
authors.forename: F
authors.initials: F
authors.lastname: Machavoine
authors.forename: A
authors.initials: A
authors.lastname: Arnould
authors.forename: L
authors.initials: L
authors.lastname: Chatenoud
authors.forename: M
authors.initials: M
authors.lastname: DY
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology*; D003208:Concanavalin A / Q000494:pharmacology; D006224:Cricetinae; D016207:Cytokines / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011817:Rabbits; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D016207:Cytokines; D007376:Interleukin-2; D016212:Transforming Growth Factor beta; D003208:Concanavalin A