Isozymes of acid phosphatase in normal and Calmette-Guérin bacillus-induced rabbit alveolar macrophages

The acid phosphatase activity of normal alveolar and BCG-induced alveolar macrophages has been examined. Five electrophoretically distinct forms of acid phosphatase have been identified in both normal and BCG-induced macrophages. The acid phosphatases can be divided into two major categories. One category, containing four distinct forms, is readily solubilized after repeated freezing and thawing or mechanical disruption The second category, containing one form, is firmly bound to the lysosomal membrane and can be solubilized by treatment of the lysosomal fraction with Triton X-100. The Triton-extractable acid phosphatase and the predominant aqueous soluble acid phosphatase have been shown to differ in the degree of membrane binding, in solubility, in net charge, and in molecular weight. The two pre-dominant phosphatases possess identical pH optimum and do not differ in response to enzyme inhibitors. BCG stimulation has been shown to result in a nearly twofold increase in acid phosphatase activity. A nearly proportionate increase in the major acid phosphatase forms has been observed.

Purification of the Moloney and Rauscher murine leukemia viruses by use of zonal ultracentrifuge systems

The B-IV and B-IX zonal ultracentrifuge rotors were applied to the concentration and purification of the Moloney and Rauscher murine leukemia viruses from large volumes of infected tissue culture fluids and animal materials. Potassium tartrate, potassium citrate and sucrose gradients were used to obtain viral concentrates from the density 1.16 to 1.18 zone. Proteolytic enzyme digestion of tissue culture preparations prior to zonal ultracentrifuge processing was effective in releasing virus from cell debris and producing highly purified, though nonleukemogenic, viral concentrates. Infected Rauscher mouse plasma was processed to give highly purified infectious virus fractions. A single centrifugation of crude Rauscher mouse spleen homogenates resulted in partially purified infectious concentrates with high virus particle counts.