The present invention relates to a novel protein, termed NTB-A, nucleic
acid molecules encoding the same and uses thereof. The invention also
relates to methods of regulating Natural Killer cells activity by
regulating the activity of NTBA-A in vitro, ex vivo or in vivo. The
invention also comprises methods of screening active compounds using
NTB-A or fragments thereof, or nucleic acid encoding the same, or
recombinant host cells expressing said polypeptide.