Antibodies targeting variant antigens on the surfaces of chondroitin sulfate A (CSA)-binding malaria-infected erythrocytes have been linked to protection against the complications of malaria in pregnancy. We examined the isotype/subtype profiles of antibodies that bound to variant surface antigens expressed by CSA-adherent Plasmodium falciparum in pregnant Malawian women with and without histol...

Mycobacterium leprae-specific and polyclonal immunoglobulin G (IgG) subclass and IgE antibodies in leprosy patients across the histopathological spectrum were determined by using a quantitative enzyme-linked immunosorbent assay. Antibody responses to M. leprae sonicates were detected only in IgG1, -2, and -3 subclasses. Even at 100-times-lower dilutions, very little IgG4 and IgE antibody activi...

We previously described a renal protective effect of factor B deficiency in MRL/lpr mice. Factor B is in the MHC cluster; thus, the deficient mice were H2b, the haplotype on which the knockout was derived, whereas the wild-type littermates were H2k, the H2 of MRL/lpr mice. To determine which protective effects were due to H2 vs factor B deficiency, we derived H2b congenic MRL/lpr mice from the ...

Ag administered together with specific IgG3 induces a higher Ab response than Ag administered alone, an effect requiring the presence of complement receptors 1 and 2 (CR1/2). In this study, we have investigated the fate of Ag, the development of germinal centers (GCs), and the Ab response after i.v. administration of IgG3 anti-trinitrophenyl (TNP) in complex with OVA-TNP. After 2 h, OVA-TNP was...

LPS was used to induce switching of B cells to IgG3 and, in the presence of TGF-beta, to IgG2b and IgA. Switching to all three isotypes increased with division number according to a consistent relationship that was independent of time in culture. The mode of activation altered the relationship with division, as CD40 ligand increased switching to IgA and decreased switching to IgG2b and IgG3 whe...

Mice implanted with hybridoma secreting 6-19 IgG3 anti-IgG2a rheumatoid factor (RF) with cryoglobulin activity develop acute glomerulonephritis and cutaneous leukocytoclastic vasculitis. As the RF activity is implicated in the skin, but not glomerular lesions, it is still unclear whether the renal pathogenicity is determined by 6-19 H chains alone or their combination with L chains. To address ...

The molecular weight of IgG3 myeloma proteins is about 170,000 as judged by gel filtration analyses of the light and heavy chains in 5 M guanidine-1 M acetic acid. The heavy chain of IgG3 has a molecular weight of about 60,000, which is larger by 9,000 to 10,000 than the molecular weight of the heavy chain of IgGl. Under nondenaturing conditions, an apparent molecular weight of 200,000 is obtai...

BACKGROUND Schistosoma mansoni and Plasmodium falciparum are common infections of school aged children in Kenya. They both cause enlargement of the spleen, but their relative contribution to the condition of splenomegaly remains unknown in areas where both infections are endemic. Here, we have investigated whether relatively high exposure to both infections has a clinically measurable effect on...

IgG and IgG3 antibodies to merozoite surface protein-2 (MSP-2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele-specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes...

The immunoglobulin G (IgG) subclass distribution of antibodies to merozoite surface antigen 2 of Plasmodium falciparum in Solomon Islanders showed marked skewing towards the IgG3 subclass. This was not observed with crude P. falciparum schizont antigen. IgG3 responses may be short-lived and require repeated restimulation for their maintenance. This may be provided by persistent infection (premu...