Experimental support for an immunological approach to the search for life on other planets

We propose a three-phase approach to test for evidence of life in extraterrestrial samples. The approach capitalizes on the flexibility, sensitivity, and specificity of antibody-antigen interactions. Data are presented to support the first phase, in which various extraction protocols are compared for efficiency, and in which a preliminary suite of antibodies are tested against various antigens. The antigens and antibodies were chosen on the basis of criteria designed to optimize the detection of extraterrestrial biomarkers unique to living or once-living organisms.