and wherein the antibodies retain the desired functional properties of the anti bst1 antibodies of the invention for example the invention provides an isolated monoclonal antibody or antigen binding portion thereof comprising a heavy chain variable region and a light chain variable region wherein the heavy chain variable region comprises an amino acid sequence that is at least 80 identical to an amino acid sequence selected from the group consisting of seq id nos 2 1 and 52 the light chain variable region comprises an amino acid sequence that is at least 80 identical to an amino acid sequence selected from the group consisting of seq id nos 4 3 and 53 and the antibody binds to human bst1 such antibodies may bind to human bst1 with an ec 50 of 50 nm or less 10 nm or less 1 nm or less 100 pm or less or more preferably 10 pm or less the antibody may also bind to cho cells transfected with the human bst1 in various embodiments the antibody can be for example a human antibody a humanized antibody or a chimeric antibody in other embodiments the v h and or v k amino acid sequences may be 85 90 95 96 97 98 or 99 homologous to the sequences set forth above an antibody.