Apoptosis of human naive NK cells mediated by a rat IgG2b anti CD2 mAb through a fractricidal ADCC reaction.
LO-CD2a/BTI-322, a rat anti human CD2 mAb, shows in vitro and in vivo immunosuppressive properties and induces T-cell depletion resulting partially from an antibody dependent cellular cytotoxicity (ADCC) mediated by NK cells. The aim of this paper is to study the in vitro effect of LO-CD2a/BTI-322 on NK cells, the majority of them also expressing the CD2 molecule. The addition of the mAb to purified naive NK cells induces apoptosis of CD2+ cells. The apoptosis is rapid, Fas ligand independent and completely inhibited by the calcium chelator EGTA, suggesting a fractricidal ADCC reaction and implying that NK cells are not resistant to lysis when used as target cells. At the end of the reaction, the CD2 - remaining cells are still capable of natural cytotoxicity against K562 cells, but at a lower rate than untreated cells.
Nizet
Y
Y
Experimental Immunology Unit, Faculty of Medicine, University of Louvain, Brussels, Belgium. latinne@imex.ucl.ac.be
Chentoufi
A A
AA
Havaux
X
X
Kinet
I
I
Cormont
F
F
Bazin
H
H
Latinne
D
D
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology*; D017209:Apoptosis; D018801:CD2 Antigens / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020287:In Situ Nick-End Labeling; D007694:Killer Cells, Natural / Q000187:drug effects*; D051381:Rats
D000911:Antibodies, Monoclonal; D018801:CD2 Antigens; C105249:LO-CD2a