Bacterial superantigens, such as staphylococcal enterotoxin B (SEB), can trigger acute pathologic effects in humans. A hydrophobic loop on the surface of SEB and other bacterial superantigens, centered around a conserved leucine (L45) residue, is essential for binding to class II major histocompatibility complex molecules. Single residue changes of wild type SEB, designated Q43P, F44P, or L45R,...

Loss of tolerance in systemic lupus erythematosus (SLE) leads to the generation of autoantibodies, which accumulate in end-organs where they induce disease. Here we show that immunoglobulin (Ig)G2a and 2b autoantibodies are the pathogenic isotypes by recruiting FcgammaRIV expressing macrophages. Class switching, but not development, of IgM anti-self B cells to these pathogenic subclasses requir...

Protamine sulphate/DNA complexes have been shown to protect DNA from DNase digestion in a lipid system for gene transfer. A DNA-based vaccine complexed to protamine sulphate was used to induce an immune response against Schistosoma mansoni anchored-glycosylphosphatidylinositol tegumental antigen in BALB/c mice. The protection elicited ranged from 33 to 44%. The spectrum of the elicited immune r...

A transplantable plasma cell leukemia cell line, designated as S27, was established from a 12-month-old female New Zealand Black mouse (NZB); serum showed polyclonal elevation of gamma globulin with agarose-agar gel electrophoresis. Immunoelectrophoretic analysis of the serum showed precipitation lines in the IgG1, IgG2a, IgG2b and IgM regions. The amount of serum immunoglobulin increased rapid...

Knowledge of the processes that underlie IgG subclass switching could inform strategies designed to counteract infections and autoimmunity. Here we show that TLR7 ligands induce subsets of memory CD4 and CD8 T cells to secrete interferon γ (IFNγ) in the absence of antigen receptor stimulation. In turn, TLR ligation and IFNγ cause B cells to express the transcription factor, T-bet, and to switch...

A cDNA clone (Tgzy85d11.r1) obtained from the Toxoplasma Expressed Sequence Tag project was chosen due to its homology with proteins of the heat shock 90 family. The cDNA encodes 137 amino acids of the C-terminal portion of the Toxoplasma Hsp90 protein (TgHsp90). Serum samples obtained from orally infected BALB/c and C57BL/6 mice showed reactivity against a recombinant TgHsp90 (rTgHsp90) after ...

Mouse macrophage elastase, a metalloproteinase secreted by inflammatory macrophages, catalyzed the limited proteolysis of selected subclasses of mouse immunoglobulins, including monomeric IgG2a, IgG3, and some forms of IgG2b. Mouse IgG1 was resistant to elastase degradation; however, human IgG1 was degraded. IgG3 in immune complexes was cleaved in a manner similar to that of monomeric IgG3. Deg...

Abstract Despite being a vaccine-preventable disease, seasonal influenza is responsible for thousands of hospitalizations and deaths yearly. Currently licensed quadrivalent inactivated virus vaccines (QIV) aim to induce neutralizing antibodies but are poor inducers T-cell responses, which could be potentially overcome with adjuvants. We evaluated adjuvant skewing host-immune responses after vac...

Objective(s): A new strategy in recent studies is using effective tuberculosis (TB) subunit vaccines combined with appropriate carriers and adjuvants which have shown promising results in preclinical and clinical studies. The aim of the present study was to evaluate the PLGA:DDA hybrid nanoparticles (NPs) for subcutaneous delivery of a novel multistage subunit vaccine ...