Evidence for multiple mechanisms of polyclonal T cell activation in murine lupus

Individuals with systemic autoantibody-mediated diseases such as lupus have polyclonal T and B cell activation. Yet, autoantibody production is restricted to certain autoantigens. The mechanisms underlying this phenomenon remain unclear. We propose three potential mechanisms by which autoreactive helper T cell responses diversify to become polyclonal, yet are restricted to certain antigens. First, using a model where self-Ig peptides spontaneously activate T cells and modulate disease in lupus mice, we demonstrate that the numbers of autoantibody-augmenting T helper peptides increased across the Ig molecule as mice aged ("intramolecular determinant spreading"). Secondly, a single T cell hybridoma established from a (NZB x NZW)F1 mouse immunized with one self-Ig peptide recognized several Ig-derived determinants, which had little sequence homology with the immunizing peptide. Such determinant degeneracy can lead to polyclonality. To explore a mechanism for restriction to certain autoantigens, a protein database search was done for homologies with sequences of selected stimulatory Ig peptides. Identical sequences of such determinants were not found in murine proteins other than Ig. These occurred infrequently in nonautoantibody Ig, but quite commonly in lupus-related autoantibodies such as antibodies to DNA, cardiolipin, and erythrocytes. Thus, determinant spreading and degenerate recognition in T cells coupled with recurring use of T cell determinant sequences among autoantibodies result in polyclonality that is restricted to certain autoantigens.

Self Ig peptides that help anti-DNA antibody production: importance of charged residues

Young NZB/NZW F1 (BWF1) mice develop T cell repertoires that are spontaneously stimulated by peptides derived from the VH regions of BWF1 J558-encoded autoantibodies (autoAb) to DNA, but not to VH region peptides of a J558-encoded antibody to an exogenous antigen. Immunization of young BWF1 mice with selected Ig-derived peptides accelerates anti-DNA production and nephritis, and immune tolerance induction to a combination of these determinants delays anti-DNA production and disease onset. To further characterize this immunoregulatory circuitry, we asked whether this phenomenon of spontaneous T cell activation by VH region peptides is restricted to anti-DNA Ab of the VH J558 family, and what are the charge and structural attributes of these T cell determinants? We studied spontaneous T cell proliferative responses to peptides derived from an autoAb to DNA constructed from VH 7183 and found that it contains several T cell determinants. Both charge and size of certain amino acids (AA) within each peptide seemed to be important. Peptides containing arginine (R) or glutamic acid (E) were more likely to be T cell determinants than peptides without those AA; replacement of charged AA with uncharged AA abolished T cell recognition of a peptide. We previously reported that some Abs to DNA are enriched in R in their VH; pathogenic BWF1 IgG anti-DNA are enriched in positively and negatively charged AA in VH regions. Therefore, we speculate that peptides from natural IgM autoAb may initially activate BWF1 T cells, and as somatic mutations of Ig occur, charged AA introduced into V regions increase the number of T cell determinants, thus favoring upregulation of pathogenic Ab subsets. Therefore, in predisposed individuals, the ability of T cells to recognize more charged T cell determinants in autoAb may be one mechanism promoting development of disease.

Reciprocal T-B determinant spreading develops spontaneously in murine lupus: implications for pathogenesis

Recent work from several laboratories has shown that, in contrast to the widely held notion that one autoimmune disease is caused by one or a few related autoantigenic determinants, autoimmunity is fundamentally a continuously evolving process. The autoimmune responses shift, drift and diversify with time not only to other determinants in the original antigen but also to other antigens. We have described a form of determinant spreading--reciprocal T-B determinant spreading--where the induction of first T cells by peptides from an autoantibody molecule could lead to help provided to a variety of B cells displaying a cross-reactive version of the original determinant. The response spreads in this way by reciprocal T-B stimulation until large cohorts of T and B cells have expanded. Such spontaneous expansion must be important in clinical disease, since tolerance induction to a limited set of T-cell determinant peptides derived from an anti-DNA antibody VH region delayed the appearance of IgG anti-dsDNA antibodies and onset of lupus nephritis in the NZB/NZW F1 mouse model of systemic lupus erythematosus. Understanding the diversification patterns in autoimmune responses has enormous implications in developing peptide-targeted therapies.

Effect of potash alum (aluminium potassium sulphate) on human semen and sperm

25 normal and healthy human volunteers were engaged in this investigation. The different concentration of potash alum solution have different effects on sperm, motility/death and fructose level of the semen. Higher concentration have higher effects.

Solitary fibrous tumor of urinary bladder: report of two cases

The clinical and pathologic features of two cases of solitary fibrous tumor arising from urinary bladder wall are described. To our knowledge, solitary fibrous tumors have not been previously reported at this site. Both tumors showed typical histologic features of solitary fibrous tumor, were CD34 immunostain positive and pursued a benign clinical course on short term follow-up.

Neonatal peptide exposure can prime T cells and, upon subsequent immunization, induce their immune deviation: implications for antibody vs. T cell-mediated autoimmunity

Neonatal exposure to antigen is believed to result in T cell clonal inactivation or deletion. Here we report that, contrary to this notion, neonatal injection of BALB/c mice with a hen egg lysozyme peptide 106-116 in putative "tolergenic" doses induced a T cell proliferative and an immunoglobulin G (IgG) antibody (Ab) response of both T helper cell 1 (Th1)- (IgG2a, IgG2b, and IgG 3) and Th2-dependent (IgG1) isotopes. Upon subsequent challenge with the peptide in complete Freund's adjuvant in adult life, although this neonatal regimen suppressed proliferation and the production of Th1 cytokines (interleukin[IL]-2 and interferon gamma), Th2 cytokine (IL-5, IL-4, and IL-10) secretion was increased, and the serum levels of Th1- and Th2-dependent isotypes of peptide-specific Ab remained elevated. The in vitro proliferative unresponsiveness in Th1 cells could be reversed by Abs to Th2 cytokines (IL-4 and IL-10). Thus, neonatal treatment with a peptide antigen induces T cell priming including production of IgG Abs of both Th1- and Th2-dependent isotypes. Upon subsequent peptide exposure, the peptide-specific T cell responses undergo an effective class switch in the direction of Th2, resulting in T cell proliferative unresponsiveness. Accordingly, this shift towards increased Ab production to autoantigen could be deleterious in individuals prone to antibody-mediated diseases. Indeed, neonatal treatment with a self-autoantigenic peptide from an anti-DNA monoclonal Ab (A6H 58-69) significantly increased the IgG anti-double-stranded DNA Ab levels in lupus-prone NZB/NZW F1 mice, despite suppressing peptide-specific T cell proliferation. This adverse clinical response is in sharp contrast to the beneficial outcome of neonatal treatment with autoantigens in Th1-mediated autoimmune diseases, such as autoimmune encephalomyelitis, as reported by others. A Th1 to Th2 immune deviation can explain the discordant biological responses after the presumed induction of neonatal tolerance in autoantibody- vs. Th-1 mediated autoimmune diseases.

A syndrome of fibrosing pleuritis, pericarditis, and synovitis with infantile contractures of fingers and toes in 2 sisters: "familial fibrosing serositis"

We describe a family in which 2 sisters born to consanguineous parents developed childhood onset fibrosing pleuritis in association with constrictive pericarditis and bilateral deforming arthropathy of large and small joints of upper and lower extremities including flexion contractures of several fingers (camptodactyly) and toes. One patient also had mitral value prolapse. Histopathological examination of the synovium and pericardium revealed fibrosis, and ultrastructural study of synovium showed abundant inter and intracellular mesh of 9 nm microfibrils. We describe this distinct clinicopathological entity with pleiotropic manifestations, the common features of which appears to be the fibrosis of serous membranes. Therefore, the term "familial fibrosing serositis" is proposed for this entity.

Immune tolerance to autoantibody-derived peptides delays development of autoimmunity in murine lupus

Mechanisms that initiate and maintain autoantibody (autoAb) production in individuals with autoimmune diseases like SLE are poorly understood. Inadequate suppression of autoreactive T cells and/or unusual activation of T and B cells may underlie the persistence of pathogenic autoAbs in lupus. Here, we examine the possibility that in mice with lupus, autoAb molecules may be upregulating their own production by activating self-reactive T cells via their own processed peptides; downregulation of this circuit may decrease autoAb production and delay the development of lupus. We found that before the onset of clinical disease, lupus-prone (NZB/NZW) F1 [BWF1] (but not MHC-matched nonautoimmune mice) developed spontaneous T cell autoimmunity to peptides from variable regions of heavy chains (VH) of syngeneic anti-DNA mAbs but not to peptides from the VH region of an mAb to an exogenous antigen. Tolerizing young BWF1 mice with intravenous injections of autoAb-derived determinants substantially delayed development of anti-DNA antibodies and nephritis and prolonged survival. Thus, in such an autoAb-mediated disease, the presence of autoreactive T cells against VH region determinants of autoAbs may represent an important mechanism involved in the regulation of autoimmunity. Our findings show that tolerizing such autoreactive T cells can postpone the development of an autoimmune disease like SLE.

T cell determinants from autoantibodies to DNA can upregulate autoimmunity in murine systemic lupus erythematosus

(NZB x NZW) F1 (BWF1) mice develop spontaneous T cell autoimmunity to VH region determinants of syngeneic anti-DNA before the onset of clinical disease. In this study, we characterized the immunogenicity, MHC binding, and lymphokine secretion patterns induced by T cell determinants from the VH region of one such anti-DNA mAb (A6.1) and examined their role in the regulation of autoimmunity. Determinants were identified by proliferation of syngeneic splenic T cells from young, unprimed BWF1 mice in response to overlapping 12-mer peptides representing the entire VH region sequence. Immunization of young BWF1 mice with any of three determinants (A6H 34-45 [p34], A6H 58-69 [p58], and A6H 84-95 [p84]) elicited proliferative responses upon in vitro recall. Upon immunization with the whole A6.1 molecule, however, proliferative responses could be recalled only to the p58 peptide, defining this as immunodominant. The other two peptides (p34 and p84) elicited minimal or no proliferation and could be termed cryptic. Proliferative responses elicited by the cryptic determinants were restricted by a single class II (I-Ed for p34 and I-Au for p84), whereas the immunodominant p58 determinant was restricted by both I-Ed and I-Eu. The cryptic p34 and p84 bound strongly to I-Ed and I-Au, respectively, whereas the immunodominant p58 peptide bound poorly to I-Ed. A6H p84 elicited T cells that secreted lymphokines in a pattern consistent with a Th1-like phenotype, whereas p58 induced a Th2-like cytokine pattern. Immunization with p34 or p84, or adoptive transfer of a p84-reactive T cell line to young BWF1 mice significantly increased IgG anti-DNA levels, accelerated nephritis, and decreased survival. In conclusion, in BWF1 mice, autoreactive T cells recognizing both cryptic and dominant self-determinants on anti-DNA autoantibodies escape deletion or anergy induction. Furthermore, since these cells are spontaneously activated before the onset of clinical disease, they may be involved in the development of the autoimmune process.