ovalbumin and Ascariasis

Components of high molecular-weight (PI) obtained from Ascaris suum extract down-regulate the Th1/Th2-related immune responses induced by ovalbumin (OVA)-immunization in mice. Furthermore, the PI down-modulates the ability of dendritic cells (DCs) to activate T lymphocytes by an IL-10-mediated mechanism. Here, we evaluated the role of toll like receptors 2 and 4 (TLR2 and 4) in the modulatory effect of PI on OVA-specific immune response and the PI interference on DC full activation. An inhibition of OVA-specific cellular and humoral responses were observed in wild type (WT) or in deficient in TLR2 (TLR2(-/-)) or 4 (TLR4(-/-)) mice immunized with OVA plus PI when compared with OVA-immunized mice. Low expression of class II MHC, CD40, CD80 and CD86 molecules was observed in lymph node (LN) cells from WT, TLR2(-/-) or TLR4(-/-) mice immunized with OVA plus PI compared with OVA-primed cells. We also verified that PI was able to modulate the activation of DCs derived from bone marrow of WT, TLR2(-/-) or TLR4(-/-) mice induced in vitro by agonists of TLRs, as observed by a decreased expression of class II MHC and costimulatory molecules and by low secretion of pro-inflammatory cytokines. Its effect was accompanied by IL-10 synthesis. In this sense, the modulatory effect of PI on specific-immune response and DC activation is independent of TLR2 or TLR4.

Topics: Animals; Antigens, Helminth; Ascariasis; Ascaris suum; B7-1 Antigen; B7-2 Antigen; CD40 Antigens; Cell Proliferation; Dendritic Cells; Histocompatibility Antigens Class II; Hypersensitivity, Delayed; Immunomodulation; Interleukin-10; Lymph Nodes; Lymphocyte Activation; Membrane Proteins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Ovalbumin; Th1 Cells; Th2 Cells; Toll-Like Receptor 2; Toll-Like Receptor 4

Six different immunisation regimes were used in an attempt to elevate the concentration of ovine IgE. The response was measured by a passive cutaneous anaphylaxis (PCA) test. These regimes included infection with Ascaris suum and the combination of infection and parenteral administration of Ascaris antigens and ovalbumin in adjuvants. The regime producing the highest titre of IgE was the combination of Ascaris infection with parenteral administration of Ascaris extract in Bordetella pertussis. This regime consistently produced a transient high titre (1:1280-1:2560) of serum IgE 9-12 days after immunisation. The response to ovalbumin was transient and the maximum PCA titre obtained was 1:10.

Topics: Administration, Oral; Alum Compounds; Animals; Antigens, Helminth; Ascariasis; Ascaris suum; Bacterial Vaccines; Body Fluids; Female; Immunization; Immunization Schedule; Immunoglobulin E; Ovalbumin; Ovum; Pertussis Vaccine; Sheep

A reductive approach was used to examine the potentiation of IgE responses by nematode infection. Ascaris homogenized extract, Ascaris pseudocoelomic (body) fluid (ABF) and purified Ascaris allergen (ABA) were tested for their ability to act as protein carriers and as mediators of potentiated IgE responses to third-party (ovalbumin; OVA) responses. All three nematode products were excellent protein carriers for the hapten dinitrophenol and showed significantly better activity in this respect than OVA. Neither ABF nor ABA enhanced the level of the IgE response to the third-party antigen but both prolonged the response markedly. ABF, but not ABA, induced high levels of total circulating IgE when given at the same time as OVA with alum. The data suggest that the enhancement and prolongation of IgE responses by nematodes may be two separate but related activities.

Topics: Allergens; Animals; Antibodies, Helminth; Antigens; Antigens, Helminth; Ascariasis; Ascaris suum; Carrier Proteins; Dinitrobenzenes; Female; Immunoglobulin E; Immunoglobulin G; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Rats; Rats, Sprague-Dawley; Solubility

Type-I hypersensitivity reactions were induced in guinea pigs by repeated topical/conjunctival application of fluoresceinyl ovalbumin (FL-OA). The ocular reactivity in early responding animals was maximal between 16 and 25 days and decreased exponentially thereafter. Desensitized eyes responded minimally to compound 48/80 but maximally to histamine. Unilateral sensitization and challenge with FL-OA produced desensitization of the immunized eye, but the reactivity of the contralateral eye persisted. A significant reduction in conjunctival stained mast cells was found in repeatedly challenged eyes. The desensitization therefore was due to a loss of reactive mast cells. Systemic infection with Ascaris suum, after repeated topical challenge with FL-OA had led to desensitization, produced a reappearance of type-I hypersensitivity reactions toward both FL-OA and ascarid antigens.

Topics: Administration, Topical; Animals; Ascariasis; Conjunctival Diseases; Desensitization, Immunologic; Enzyme-Linked Immunosorbent Assay; Female; Guinea Pigs; Histamine; Hypersensitivity; Immunization; Mast Cells; Ovalbumin; p-Methoxy-N-methylphenethylamine

Topics: Animals; Antibody Formation; Antibody-Producing Cells; Ascariasis; Erythrocytes; Female; Hypersensitivity, Delayed; Immunoglobulin G; Immunoglobulin M; Immunosuppression Therapy; Mice; Ovalbumin; Spleen