|Common tolerance mechanisms, but distinct cross-reactivities associated with gp41 and lipids, limit production of HIV-1 broad neutralizing antibodies 2F5 and 4E10.|
Chen, Y; Zhang, J; Hwang, KK; Bouton-Verville, H; Xia, SM; Newman, A; Ouyang, YB; Haynes, BF; Verkoczy, L
Journal of immunology (Baltimore, Md. : 1950)
Developing an HIV-1 vaccine has been hampered by the inability of immunogens to induce broadly neutralizing Abs (BnAbs) that protect against infection. Previously, we used knockin (KI) mice expressing a prototypical gp41-specific BnAb, 2F5, to demonstrate that immunological tolerance triggered by self-reactivity of the 2F5 H chain impedes BnAb induction. In this study, we generate KI models expressing H chains from two other HIV-1 Abs, 4E10 (another self-/polyreactive, anti-gp41 BnAb) and 48d (an anti-CD4 inducible, nonpolyreactive Ab), and find a similar developmental blockade consistent with central B cell deletion in 4E10, but not in 48d VH KI mice. Furthermore, in KI strains expressing the complete 2F5 and 4E10 Abs as BCRs, we find that residual splenic B cells arrest at distinct developmental stages, yet exhibit uniformly low BCR densities, elevated basal activation, and profoundly muted responses to BCR ligation and, when captured as hybridoma mAb lines, maintain their dual (gp41/lipid) affinities and capacities to neutralize HIV-1, establishing a key role for anergy in suppressing residual 2F5- or 4E10-expressing B cells. Importantly, serum IgGs from naive 2F5 and 4E10 KI strains selectively eliminate gp41 and lipid binding, respectively, suggesting B cells expressing 2F5 or 4E10 as BCRs exhibit specificity for a distinct spectrum of host Ags, including selective interactions by 2F5 BCR(+) B cells (i.e., and not 4E10 BCR(+) B cells) with those mimicked by its gp41 neutralization epitope.
|Soluble receptor for advanced glycation end products alleviates nephritis in (NZB/NZW)F1 mice.|
Lee, SW; Park, KH; Park, S; Kim, JH; Hong, SY; Lee, SK; Choi, D; Park, YB
Arthritis and rheumatism
To investigate the efficacy of different doses of the soluble form of the receptor for advanced glycation end products (sRAGE) (conjugated to the Fc portion of immunoglobulin) in the treatment of nephritis in lupus-prone mice, in comparison with the efficacy of combination therapy with mycophenolate mofetil plus prednisolone.Twenty-eight female (NZB/NZW)F1 mice were divided into 5 groups (untreated, sRAGE [dose groups of 0.5, 1, or 2 μg], or mycophenolate mofetil plus prednisolone). Proteinuria and histologic damage were evaluated. Immune complex deposition and the nuclear translocation of NF-κB in the kidney tissue were assessed by immunofluorescence staining. Serum concentrations of anti-double-stranded DNA (anti-dsDNA) and IgG subclasses were also measured. The population of T cells was evaluated using a fluorescence-activated cell sorter, and expression of intracellular adhesion molecule 1 and vascular cell adhesion molecule 1 in the kidney tissue was assessed by immunohistochemical staining.In comparison with untreated mice, mice treated with 1 or 2 μg sRAGE showed significantly reduced proteinuria and attenuated histologic renal damage, with efficacy comparable to that of combination therapy. Treatment with 2 μg sRAGE significantly reduced immune complex deposition and decreased the serum concentrations of anti-dsDNA, IgG2a, IgG2b, and IgG3. In addition, sRAGE interrupted the nuclear translocation of NF-κB in the kidney, resulting in reduction in the expression of downstream genes of NF-κB in vivo and in vitro. Furthermore, sRAGE effectively modified T cell populations.Treatment with sRAGE significantly improved nephritis in lupus-prone mice, with efficacy comparable to that of standard induction treatment for lupus nephritis. These data suggest that sRAGE has antiinflammatory effects on the pathophysiology of lupus nephritis and could serve as a potent new therapy for this disease.
|Forced miR-146a expression causes autoimmune lymphoproliferative syndrome in mice via downregulation of Fas in germinal center B cells.|
Guo, Q; Zhang, J; Li, J; Zou, L; Zhang, J; Xie, Z; Fu, X; Jiang, S; Chen, G; Jia, Q; Li, F; Wan, Y; Wu, Y
By inhibiting target gene expression, microRNAs (miRNAs) play major roles in various physiological and pathological processes. miR-146a, a miRNA induced upon lipopolysaccharide (LPS) stimulation and virus infection, is also highly expressed in patients with immune disorders such as rheumatoid arthritis, Sjögren's syndrome, and psoriasis. Whether the high level of miR-146a contributes to any of these pathogenesis-related processes remains unknown. To elucidate the function of miR-146a in vivo, we generated a transgenic (TG) mouse line overexpressing miR-146a. Starting at an early age, these TG mice developed spontaneous immune disorders that mimicked human autoimmune lymphoproliferative syndrome (ALPS) with distinct manifestations, including enlarged spleens and lymph nodes, inflammatory infiltration in the livers and lungs, increased levels of double-negative T cells in peripheral blood, and increased serum immunoglobulin G levels. Moreover, with the adoptive transfer approach, we found that the B-cell population was the major etiological factor and that the expression of Fas, a direct target of miR-146a, was significantly dampened in TG germinal center B cells. These results indicate that miR-146a may be involved in the pathogenesis of ALPS by targeting Fas and may therefore serve as a novel therapeutic target.