title: Rheumatoid factor-like IgM in Plasmodium berghei (Apicomplexa: Haemosporida) infections of BALB/c mice.
abstract: Groups of female BALB/c mice infected by intravenous injection with 50 erythrocytes containing Plasmodium berghei Vincke et Lips, 1948 were sacrificed on days 3 through 12 after infection. Rheumatoid factor-like IgM (RF-IgM) and parasite-specific IgG levels were determined by enzyme-linked immunosorbent assay in serum specimens and in culture medium removed from spleen cell cultures established at sacrifice. All four mouse IgG subisotypes were recognized by RF-IgM molecules induced by Plasmodium berghei infection, and in this regard, the parasite-induced RF-IgM response resembled that induced by lipopolysaccharide polyclonal activation. Plasmodium berghei infection resulted in a biphasic RF-IgM response, with infected animals demonstrating significantly increased levels of RF-IgM early in the infection and significantly decreased levels late in the infection, compared to uninfected control mice. The decreased levels of RF-IgM observed late in infection correlated with increasing parasitaemia levels, and were primarily due to a decrease in RF-IgM specific for mouse IgG2a. Late infection levels of RF-IgM specific for IgGI, IgG2b, and IgG3 were not significantly different from those of control animals.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: Reuel Robert
authors.initials: RR
authors.lastname: Hook
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Green
authors.forename: Melissa K
authors.initials: MK
authors.lastname: Stuart
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology; D005260:Female; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification / Q000378:metabolism; D007075:Immunoglobulin M / Q000097:blood / Q000378:metabolism*; D008288:Malaria / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018512:Parasitemia / Q000276:immunology; D010962:Plasmodium berghei / Q000276:immunology; D012217:Rheumatoid Factor / Q000097:blood / Q000378:metabolism; D013154:Spleen / Q000276:immunology; D013997:Time Factors
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor