Ig purity depends on the species of the source material. MSP-1p42 specific titers of the Ig preparations, Panel A (rabbit samples), Panel B, C (human samples) were determined by ELISA and then adjusted to the pre-purification titer. All rabbit samples were diluted 1:50 and all human samples were diluted 1:10 to achieve optimal band resolution. Lanes: 1) molecular weight marker, 2) source material (pre-purification), 3) MW marker, 4) Protein G-purified Ig, 5) Protein A/G-purified Ig, 6) CA-AS-purified Ig and 7) PEG-purified Igs. Samples in Panel A, B were tested immediately following purification. Samples in Panel C were tested for their stability after storage for 24 weeks at 4°C. Panel C, 1) MW marker, 2) Protein G-purified Ig, 3) Protein A/G-purified Ig, 4) CA-AS-purified Ig and 5) PEG-purified Igs.