Improved salt fractionation of animal serums for immunofluorescence studies.

With all animal serums studied except rat serum, an improved salt fraction that contained a high percentage of gamma-globulin and little or no albumin could be obtained by using optimal ammonium sulfate concentrations. These concentrations were less than the routinely used half-saturated solutions and different from the sometimes quoted one-third-saturated solutions. These are simple, economical methods for obtaining the antibody-containing globulin fractions from the serums of a variety of animals commonly used as antibody producers for immunofluorescence applications. Fluorescent antibody reagents prepared in this laboratory from serum fractions obtained by these optimal procedures provided conjugates that may be superior to those prepared from fractions obtained with a higher and uniform salt concentration.