Changes in Mouse Serum Proteins during Acute and Chronic Infection with an Intracellular Parasite (Toxoplasma Gondii)

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Abstract
Summary: Electrophoretic and immunoelectrophoretic patterns of mouse serum proteins are markedly altered during the course of the acute and chronic stages of infection with virulent and relatively avirulent strains of Toxoplasma gondii. In mice infected with the virulent RH strain, there was a remarkable increase in α- and β-globulins and decrease in albumin. Immunoelectrophoretic patterns of serum and peritoneal fluid of these animals revealed a marked increase in haptoglobin, conversion of β1C to β1D, disappearance of two major β-globulin precipitin arcs, and an increase in mobility of albumin. Similar but less marked changes were noted in some of the groups of animals infected with less virulent strains. In mice infected with strains M7741 and H44 a state of “chronic” hypergammaglobulinemia developed. Challenge of chronically infected mice with the original avirulent strain or with the RH strain resulted in very high levels of γ-globulins in the absence, in most animals, of significant rises in serologic test titers. Adsorption of such sera with proliferative organisms resulted in disappearance or marked decrease in antibodies but had no demonstrable effect on γ-globulin levels. These findings are discussed in relation to the chronic infection in animals and humans, and an hypothesis is posed suggesting the existence of a form of the parasite other than the cyst to account for persistent antibody formation, hypergamma-globulinemia and parasitemia.