Distinctive immunoglobulin E anti-house dust allergen-binding specificities in a tropical Australian Aboriginal community

BACKGROUND: There is evidence that the specificity of the IgE binding in allergy tests can vary for different populations. OBJECTIVE: We aimed to examine the allergenic specificity of IgE binding in sera from house dust mite (HDM)-atopic subjects in a tropical Australian Aboriginal community. METHODS: Sera shown to contain IgE antibodies to an HDM extract of Dermatophagoides pteronyssinus were examined for IgE binding to a panel of nine purified HDM allergens from this mite species by quantitative microtitre assays. IgG antibody binding (IgG1 and IgG4) was also measured. RESULTS: The IgE-binding activity in the sera from the Aboriginal community was not directed to the expected major groups 1 and 2 HDM allergens but instead to the group 4 amylase allergen. There was also little IgE binding to the potentially cross-reactive tropomyosin (Der p 10) or arginine kinase (Der p 20) allergens. The IgG4 antibody was rarely detected and limited to the Der p 4 allergen. IgG1 antibody binding was frequently measured to all the allergens regardless of an individual's atopic status, whereas in urban communities it is restricted to the major allergens and to atopic subjects. CONCLUSION: The high IgE anti-HDM response of Australian Aboriginals predominantly bound Der p 4 and not the Der p 1 and 2 allergens, showing a distinctive allergy that could affect the disease outcome and diagnosis.     

Die Insuffizienz der intraabdominellen Infektabwehr bei der eitrigen Peritonitis — Folge einer gestörten Fremdkörperopsonierung

Summary Despite a high concentration of serum proteins and intact phagocytes peritonitis exudates contain a large number of viable, pathogenic bacteria. The reason for this biological paradox is unknown. Our investigations reveal a pronounced defect in humoral opsonization of foreign particles in peritonitis exudate. We evaluated a modified chemiluminescence system allowing the determination of opsonic activity in serum and exudate. In serum we found a close correlation between opsonic activity and immunologically measurable levels of C₃-complement and IgG. In purulent peritonitis exudates, however, the actual opsonizing activity was much less than expected according to the opsonin concentrations. We found a pronounced difference between immunologically determined opsonin levels and impaired opsonic function. Employing crossed immunoelectrophoresis massive C₃-splitting into smaller fragments could be demonstrated in peritonitis exudates. In these exudates we found very high concentrations of granulocyte proteolytic (elastase) and oxidative (myeloperoxidase) enzymes which may lead to a functional destruction of opsonins followed by impaired opsonization in peritonitis exudate. The great number of bacteria and foreign particles in addition can cause a pronounced physiological consumption of complement components. The almost complete breakdown of intact C₃-complement in intraabdominal exudate explains the deficient host defence in patients with severe peritonitis.

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Abkürzungsverzeichnis CL Chemilumineszenz - IgG Immunglobulin G - OK Opsonierungskapazität     

Solid phase C1q microassay for the rapid detection of circulating immune complexes

A C1q solid phase microassay was designed for the rapid detection of circulating immune complexes. Its level of sensitivity is comparable to that of the Raji cell and greater than the C1q binding assay; furthermore, it is faster and low in cost. These conditions make it more practical and applicable in the clinical setting.     

PENA方法的建立及与ELISA IgM检测CMV的比较

目的　介绍一种敏感、稳定、快速、简便的实验室检测CMV的方法 ,同时探讨该种新方法与ELISA检测CMV方法的优、缺点。方法　对 5 5 2例病人应用间接荧光免疫法测定细胞核中的特异病毒早期抗体 (PENA)和ELISA法测定IgM抗体。结果　PENA方法 :强阳性 88例 ,阳性率 15 4 9% ,弱阳性 2 73例 ,阳性率 5 9 4 6 % ;ELISA -IgM方法 :阳性 34例 ,阳性率6 16 %。结论　PENA方法操作简便 ,与ELISA方法相比较 ,可对CMV感染进行早期测定及诊断 ,并可区分既往感染和即时感染 ,具有敏感性和稳定性 ,是测定小儿CMV感染的一种较好的方法     

Regulation of secretion of IL-4 and IgG1 isotype by melatonin-stimulated ovalbumin-specific T cells

In the present study, we describe the potential role of melatonin, a pineal hormone, in regulating the activation of the antigen-specific T cell response. Melatonin encouraged the proliferation of Th cells and improved their ability to secrete IL-4, but down-regulated the levels of IL-2 and interferon-gamma (IFN-γ). Melatonin, however, could not exert any influence on the T cells of unprimed mice. On studying the regulation of subclass of IgG isotype, melatonin specifically enhanced the secretion of antigen-specific IgG1 antibodies and decreased the yield of IgG2a isotype. The results suggest that melatonin possibly acts by selectively activating a Th2-like immune response.     

Evaluation of Onchocerca volvulus-specific IgG4 subclass serology as an index of onchocerciasis transmission potential of three Gabonese villages

The major objective of this study was to evaluate the usefulness of IgG4 ELISA and Western blot analysis, using a crude extract of Onchocerca volvulus adult worms as antigens, for diagnosing onchocerciasis in a Gabonese paediatric population with mixed filarial infections. The subjects had loaisis, streptocercosis or mansonellosis in addition to onchocerciasis. Control sera from loaisis or mansonellosis subjects residing outside the endemic zone were used to provide the cut-off point for positive results. The IgG4 ELISA had a specificity of 96% but a lower sensitivity of 78·7%. It detected 25 onchocerciasis cases out of 65 individuals who were negative on parasitological examination. Furthermore, the ELISA provided a more accurate picture of onchocerciasis transmission in a village with very low skin microfilartal load. A 27·5-kD antigen was identified on Western blots as a marker of onchocerciasis. The paediatric population provided a reliable window for assessing the parasitologic and serologic parameters in the three villages with disparate levels of onchocerciasis transmission.     

Humoral Immunity to Dietary Antigens in Atopic Dermatitis

Enzyme-linked immunosorbent assays (ELISA) employing a biotin-avidin amplification step are described for the quantification of human serum IgG antibodies to the dietary antigens ovalbumin (OA) and beta-lactoglobulin (BLG). The analytical quality of these assays was acceptable. Antibodies were measured in 16 patients with mild or moderate atopic dermatitis (AD), in 31 patients with a history of AD, and in closely matched controls. Levels of serum anti-OA antibodies did not differ in patients and controls, whereas anti-BLG antibodies tended to be higher in patients with mild or moderate AD than in controls (P less than 0.05).     

Transport of Proteins Across the Human Placenta

PROBLEM: The transport of various proteins across the human placenta was investigated by comparing maternal and fetal concentrations of tetanus antigen (TT-AG), anti-tetanus (TT)-immunoglobulin G (IgG) (following maternal vaccination), IgA, human chorionic gonadotropin (hCG), human placental lactogen (hPL), and alpha-fetoprotein (AFP) at term. METHOD OF STUDY: The concentrations of the six proteins were determined using enzyme-linked immunosorbent assay in serum of maternal venous and umbilical (fetal) vein samples obtained at delivery from uncomplicated term pregnancies (n = 16). RESULTS: The ratios (mean ± standard deviation) of fetal (umbilical) to maternal level were 1.41 ± 0.33 (anti-TT-IgG), 0.91 ± 0.37 (TT-AG), 0.002 ± 0.001 (IgA), 0.003 ± 0.001 (hCG), and 0.008 ± 0.004 (hPL), while the maternal:fetal concentration ratio of AFP was 0.002 ± 0.002. IgA, hCG, hPL, and AFP showed a close correlation between maternal and fetal levels varying between r² = 0.47 to 0.73 (P < 0.004–0.0001). Because AFP is produced by the fetus while IgA originates in the mother, the appearance of small amounts of these two proteins in the maternal or fetal compartment, respectively, suggests a slow rate of diffusion following a high concentration gradient. The detection of hCG and hPL in fetal serum is also interpreted as diffusion from the maternal into the fetal blood. Anti-TT-IgG has a significantly higher concentration in the fetal as compared with the maternal serum, which is in line with the well-documented active transfer of IgG. Fetal TT-antigen levels were similar to maternal concentrations, showing a close correlation (r² = 0.74, P < 0.0001) between the two proteins. CONCLUSIONS: The correlation between maternal and fetal concentrations of various proteins like IgA (150,000 Da), hCG (42,000 Da), and hPL (21,000 Da) suggests passive diffusion of these macromolecules across the placenta from the maternal to the fetal side, albeit at a slow rate. A similar process is postulated for AFP (70,000 Da) diffusing in the opposite direction from the fetus to the mother. There was no significant difference between the transplacental fetomaternal gradient of IgA and hCG and the maternal-fetal gradient of AFP. In view of the substantially larger volume of circulating maternal as compared with fetal blood, a significantly higher rate of crossing of AFP as compared with the other proteins must be assumed. It is uncertain whether a difference in the rate of transplacental transfer in the two directions or an additional source of AFP production in the maternal compartment explains the high maternal level. Anti-TT-IgG concentration is significantly higher in fetal than in maternal serum suggesting active transfer from the mother to the fetus. Furthermore, there is considerable transfer of TT-AG and a close correlation of fetal:maternal ratios of anti-TT-IgG (150,000 Da) and TT-AG (150,000 Da) could be an indication for a specific transfer of the antigen antibody complex.     

Monoclonal antibodies to three distinct epitopes on human IgE: their use for determination of allergen-specific IgE

Three different monoclonal antibodies (MAb) against human immunoglobulin E have been obtained which specifically bind to human myeloma and polyclonal IgE. The antibodies showed high avidities for soluble IgE (0.7 X 10(9) to 3.3 X 10(9) M-1). These MAb defined three distinct epitopes on IgE. A mixture of these antibodies in combination with an 125I-labelled anti-mouse Kappa chain MAb has been used to measure allergen-specific IgE. This determination was performed by a solid-phase radioimmunoassay using allergen extracts coated to either chemically activated paper discs or to polyvinyl chloride wells. This method is 4-10 times more sensitive than other previously reported procedures. A similar technique has also been applied to detect individual allergens in immunoblots of allergen extracts.     

Identification of bovine IgG as a major cross-reactive vertebrate meat allergen

BACKGROUND: Although beef is a main source of protein in Western diets, very little has been published on allergic reactions to beef or the main allergens implicated in these reactions. The aim was to evaluate the IgE antibody response to beef in suspected meat-allergic subjects and assess cross-reactivity of beef with other vertebrate meats. METHODS: Fifty-seven sera from suspected meat-allergic subjects were tested by grid blot for specific IgE antibodies to vertebrate meats (beef, lamb, pork, venison, and chicken), and the patterns of recognition of meat proteins were assessed by immunoblot studies. RESULTS: A 160-kDa band, identified as bovine IgG, was detected in raw beef in 83% (10/12) of beef-allergic subjects but in only 24% of the beef-tolerant subjects. IgE reactivity to a band of similar mol. mass was detected also in lamb and venison, but rarely in pork or chicken. Complete inhibition of the IgE reactivity to the bovine IgG was obtained with lamb, venison, and milk. IgE reactivity to this band also completely disappeared when beef or lamb extracts were separated under reducing conditions, indicating conformational epitopes. CONCLUSIONS: Bovine IgG appears to be a major cross-reacting meat allergen that could predict beef allergy. Further studies with oral IgG challenges should be performed to document the conclusion that in vitro reactivity correlates with clinical hypersensitivity. The role of bovine IgG in other bovine products such as milk, dander, or hair must also be studied, and the hypothesis that it is a cross-reacting allergen with other mammalian products validated.