Immunitat und Infektion最新文献

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by the deficiency of glycosylphosphatidylinositol-(GPI-)-anchored surface molecules on blood cells. The biochemical basis of this deficiency is the lack of the first GPI biosynthesis intermediate GlcNAc-PI in the deficient cells corresponding to that in Thy-1- mouse lymphoma mutants of the class A. Recently, the responsible gene (PIG-A gene) has been cloned. Here, PIG-A transcripts in T-, NK- and EBV-transformed B cell lines of different PNH patients have been analyzed. In contrast to the uniform biochemical defect, these molecular analyses reveal heterogenous mutations of the PIG-A gene in different PNH patients.

In five patients with chronic pancreatitis we found secretory IgA (sIgA) in the pancreatic juice. In four control persons this was seen only in one case. In pancreatic tissue of three patients with chronic pancreatitis we detected both, IgA and secretory component by immunohistology. We suggest that sIgA in the pancreatic juice was partly produced in the pancreas.

The respiratory tract represents both the port of entrance of the measles virus (MV) and an important target tissue for measles complications. Therefore, mucosal immunization could be an attractive alternative to the current subcutaneous route. We studied the virus-specific IgA and IgG antibody response in the serum after intranasal and intragastric immunization with MV in the mouse model under non-replicating conditions. Hemagglutination-inhibiting antibodies, mostly without virus-neutralizing activity were found after intranasal immunization. No virus-specific antibodies were detected after intragastric immunization.

Basophils and mast cells represent important effector cells in allergic inflammation. Furthermore, these cell types are suggested to play a role in the pathogenesis of other forms of chronic inflammation and in the maintenance of tissue homeostasis. Recent studies provided new information on the morphology, development, distribution and effector function of the histamine-containing cells. Particularly the identification of new surface membrane molecules such as CD40 ligand on basophils or c-kit on mast cells, and of new triggering agents and modulators of mediator release such as IL-3, IL-5, GM-CSF and nerve growth factor (for basophils) or c-kit ligand (for mast cells) allows a better understanding of the regulation of these cell types. The regulating cytokines are produced by lymphocytes and tissue cells. On the same time, membrane proteins and soluble mediators of basophils and mast cells regulate tissue and immune functions. Thus, basophils and mast cells are not only effectors but also regulators of inflammation. It is, therefore, tempting to speculate that both cell types play an important role as mediator cells between the unspecific effector level and the specific antigen-recognizing cells of the host immune defense system. This review is mostly restricted to the human system.

The purpose of our study was to evaluate the effect of oral vaccination with Bordetella pertussis surface antigens on the immune response at the site of antigen application. We orally immunized female BALB/c mice on five consecutive days and repeated this procedure after a free interval of 10 days. Lymphocytes of the lung (LL), Peyer's patches (PPL) and lamina propria of the gut (LPL) were isolated and the immunoglobulin secretion rate was measured with time-resolved immunofluorescence. Oral immunization was found to enhance the IgA secretion rate by 69.9% in LL compared to unimmunized animals. The IgG synthesis in LL was increased by 28.1% and the IgM synthesis by 14.1%. In addition, an improvement of 47.8% was observed for the IgG secretion in LPL and PPL. Thus, our results demonstrate a strong local immune response after oral immunization with Bordetella pertussis.

T helper type 2 (TH2) cells are a major source of interleukin- (IL-)4 which plays a critical role in the induction of the IgE synthesis. Their counterplayers, the T helper type 1 (TH1) cells produce interferon- (IFN-)gamma which inhibits the IL-4-induced IgE synthesis. Thus, the TH2/TH1 ratio plays an important role in the regulation of the IgE synthesis. Moreover, IL-4 seems to be the crucial factor controlling the switch of T helper precursor (THp) cells to the TH2 phenotype. However, the primary cellular source of IL-4 that skews an immune response towards the TH2 phenotype is not yet known. For future prophylactic and therapeutic interventions, e.g. in allergy, it will be crucial to know the type of cell involved and the factors that are activating this cell, i.e. the exact mechanism that is controlling the switch to the TH2 phenotype.

In patients with recurrent infections, "intrinsic" asthma and lymphoma the specific binding capacity of IgG subclass 2 against pneumococcus was determined by line-immuno-binding-assay (LIBA). The results show that LIBA represents a simple and specific test system suitable as diagnostic parameter in patients with a suspected humoral defect.

In recent years, increasing evidence has accumulated to suggest that the eosinophil represents a potent cytotoxic effector cell which plays a key role in the pathogenesis of pulmonary diseases as well as other human disorders. Beside contributing to antiparasitic host defense, eosinophils can prove detrimental to a number of host organs and tissues via release of their preformed basic proteins as well as de novo generated lipid mediators or oxygen radicals. Eosinophil effector functions are stimulated by certain lipid mediators and cytokines released by other cells in the course of active disease. In addition to their effector functions, eosinophils may have other functions in immune responses. Synthesis and expression of class II proteins of the major histocompatibility complex (MHC) may enable eosinophils to serve as antigen-presenting cells, i.e. to the antigens that appear at mucosal surfaces. In addition to collaborative interactions with lymphocytes, CD4-expressing eosinophils may elaborate cytokines that can effect cells within their tissue milieu. In conclusion, the evolving understanding of eosinophils indicates that eosinophils may not only serve as end-stage effector cells but also interact cooperatively with other cellular tissue elements in related diseases.