A comparison of efficacy and specificity of three NK depleting antibodies.

This study compares in vivo efficacy and specificity of the three NK cell depleting antibodies anti-asialo GM1, anti-NK 1.1 and the recently described TM beta 1, which is directed against the interleukin-2 receptor beta chain. All three antibodies are equally efficacious as assessed by abolishing NK mediated cytolytic activity induced by a high dose virus infection or Poly IC against YAC-1 targets. Similarly, the generation of virus-specific cytotoxic T cells (CTL) was unimpaired after NK depletion in two different virus infections. However, if mice are treated with the antibodies several days after virus infection, when strong CTL responses have already been generated, anti-asialo GM1 and-to a lesser extent-also TM beta 1 have a significant effect on CTL activity. Only after treatment with anti-NK 1.1 antibody, CTL activity was not significantly impaired. We conclude, that of the NK depleting antibodies currently available, anti-NK 1.1 allows the best differentiation of activated CTL and NK cells in vivo.