From our patient cohort, we can roughly estimate the frequency of B cells that produce an antibody that recognizes melanoma cells under the assumption that a reactive antibody culture, defined as having an OD .75% of the positive control, arises from only a single B cell (1 out of 500 plated per culture). By dividing the total number positive antibody cultures from the patient cohort by the total number of B cells evaluated from the patient cohort by the number of positive antibody cultures, we roughly approximate that from our patient cohort one out of 1,765 B cells produce an antibody that may recognize melanoma cells.