Limiting dilution analysis (LDA) of cells responding to recombinant XXXX without previous stimulation: evidence that all responding cells are lymphokine-activated potent effectors.

@entity1 @entity3647 @entity137 @entity5041 @entity1199 @entity10086
The relationship between peripheral blood mononucleated cells spontaneously bearing the @entity3647 ( @entity3647 ) and cell @entity137 for the natural killer (NK)-sensitive K562 target cell line was investigated. For this purpose, three types of experiments were performed. (i) Positive selection of cells spontaneously bearing the @entity3647 was carried out by culturing peripheral blood lymphocytes (PBL) in the sole presence of recombinant @entity1199 ( @entity5041 ). @entity137 was assessed at Day 6 of the culture in a 4 hr cytotoxic assay. (ii) Negative selection was performed by complement mediated lysis using the B1.49.9 monoclonal antibody which is specific for the @entity3647 . (iii) Limiting dilution analysis of non-adherent PBL was carried out in the presence of @entity5041 alone. The colonies obtained were divided and daughter colonies assayed for anti-K562 @entity137 in a 6 hr cytotoxic assay and for proliferation. The results show that: (i) a 6-day culture of @entity1 non-adherent PBL in the presence of @entity5041 alone leads to a sharp increase in anti-K562 @entity137 ; (ii) depletion of B1.49.9 positive PBL strongly decreases @entity137 against K562 targets; (iii) limiting dilution analysis indicates that all colonies grown without activation in the presence of autologous serum and @entity5041 can mediate @entity137 against K562 targets, which is not the case when the starting population is activated. Thus, our data taken together strongly suggest that lymphocytes spontaneously bearing the @entity3647 are directly involved in K562 lysis by fresh PBL (classical NK activity). Moreover, we demonstrate that all colonies able to proliferate without any activation, in the sole presence of @entity5041 , are potent K562 killers (in this case, these cells correspond to the so-called lymphokine activated killers, @entity10086 ).
