PubMed HealthSearch

PubMed · 7933575

[Immune complex and vasculitis].

Abstract

In the early 1900s, von Pirquet first introduced the concept that antigen antibody complexes might cause disease. Since that time, systemic necrotizing vasculitis is believed to be a typical form of immune complex-mediated vasculitis and it may be found in many disorders associated with immunological abnormalities. In 1866, Kusmaul and Maier reported a case with multilesions of necrotizing vasculitis named as periarteritis nodosa which is now nominated as polyarteritis nodosa characterized by the presence of focal inflammatory lesions in small and medium-sized arteries. Besides polyarteritis nodosa, necrotizing vasculitis is frequently found in connective tissue diseases, especially in SLE and RA. Granulomatous vasculitis is a definitely different type of vasculitis from necrotizing vasculitis and known to be found in Wegener's granulomatosis. Whether or not granulomatous vasculitis is an immune complex-mediated disease is unknown, but it can be produced experimentally in several settings. In a experimental model of serum sickness, animals who are hyperimmune responders have widespread granulomatous lesions similar to Wegener's granulomatosis in histology. Intravenous injection of complete Freund's adjuvant in rabbits followed by intravenous administration of human IgM rheumatoid factor is capable of inducing a marked pulmonary granulomatous reaction. The relation of these observations to human Wegener's granulomatosis is uncertain, but the histology and location of the lesions are strikingly similar to human disease. Vasculitis involved in large and medium-sized arteries is seen in two different types of diseases known as temporal arteritis and Takayasu's arteritis. Circulating and tissue-bound immune complexes have been found in both conditions. Most common vasculitis in childhood is Schonlein-Henoch purpura in North America and Kawasaki disease in Japan.(ABSTRACT TRUNCATED AT 250 WORDS)

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S Yoshinoya. 1994. [Immune complex and vasculitis].. https://pubmed.ncbi.nlm.nih.gov/7933575/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

High doses of immunoglobulin G attenuate immune aggregate-mediated complement activation by enhancing physiologic cleavage of C3b in C3bn-IgG complexes.

Intravenously applied human IgG has beneficial effects in treating inflammatory diseases, presumably because it has a complement attenuating role. This role of IgG was studied in vitro by following C3 activation and inactivation in sera that were supplemented with exogenous human IgG and incubated with immune aggregates. IgG added at 2 to 10 mg/mL stimulated the physiologic inactivation of C3b-containing complexes twofold to threefold in 20% sera. This, in turn, lowered the overall C3 activation by 28%, as new C3 convertases primarily assembled on C3b-containing complexes. Exogenous IgG (5 mg/mL) also stimulated inactivation of purified C3b2-IgG complexes, whereby their half-life dropped from 3-4 to 1.5 minutes in 20% serum. IgG appeared to act like a modulator of factor H and I because it did not stimulate inactivation of C3b-containing complexes in factor I-deficient serum. Thus, the known partial protection of C3bn-IgG complexes from inactivation by factor H and I was downregulated by high concentrations of IgG. The ability of high doses of IgG to stimulate complement inactivation is a novel regulatory role of IgG. This may be one of the molecular principles for its therapeutic efficacy in treating complement-mediated inflammations.

Antigen-Antibody Complex

Binding of HIV-1 virions or gp120-anti-gp120 immune complexes to HIV-1-infected quiescent peripheral blood mononuclear cells reveals latent infection.

HIV-1-infected quiescent CD4+ cells harbor the virus in an inactive state until subsequent activation. The possibility that HIV-1 itself and the virus envelope glycoprotein 120 (gp120) might be important agents of this activation was investigated. The present data indicate that binding of heat-inactivated HIV-1 (iHIV-1) to infected resting PBMCs was sufficient to activate NF-kappa B and AP-1, to induce transition from the G0/G1 stage of the cell cycle to the S/G2/M stage, to induce cell surface expression of CD25, to stimulate provirus integration, and to commit cells to produce virus. The cumulative amount of HIV-1 produced by iHIV-1-stimulated cells strictly depended on the concentration of p24gag in the virion preparations used for stimulation. Moreover, virus production was not evidenced in infected resting cells exposed to iHIV-1 previously incubated with soluble CD4 (sCD4), indicating that activation requires a contact between HIV-1 envelope glycoproteins and cell surface CD4. Although soluble gp120 did not stimulate virus production, we found that transition to the S/G2/M stage of the cell cycle, cell surface expression of activation Ags, and virus production were stimulated by cross-linking of CD4 by gp120-anti-gp120 immune complexes. Finally, incubation of gp120-anti-gp120 immune complexes with sCD4 inhibited these effects. These findings suggest that virions and gp120 anti-gp120 immune complexes found in infected patients at all times of infection can stimulate virus production in CD4+ cells harboring HIV-1 in an inducible state.

Antigen-Antibody Complex

Neutrophil lactoferrin release induced by IgA immune complexes can be mediated either by Fc alpha receptors or by complement receptors through different pathways.

Our previous results showed that neutrophil secondary granule release, indicated by release of lactoferrin, was a slow process when induced by IgA immune complexes (IC) formed in heat-inactivated serum, but became very fast if IgA IC were formed in normal human serum. This phenomenon did not apply to the IC of other Ab isotypes. In this paper, we demonstrate that the fast lactoferrin release is caused by complement, mainly due to the deposition of C3b and iC3b on IgA IC. Either CR1 or CR3 can mediate the response and both receptors have to be blocked to prevent it. Complement also influences FcalphaR-mediated lactoferrin release, in that this is enhanced by the anaphylatoxin peptides, C5a and C5a(desArg). Divalent cations are required for FcalphaR and CR3- but not for CR1-mediated lactoferrin release. Genistein, a protein tyrosine kinase inhibitor, totally inhibits FcalphaR-mediated response, but has little effect on CR1-mediated response. Therefore, it is clear that different pathways of intracellular signaling are utilized. In addition, stimulation through FcalphaR promotes the receptor up-regulation, which is abolished by the presence of EDTA or genistein.

Antigen-Antibody Complex