Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.(AU)

Immune enhancement activities of silk lutein extract from Bombyx mori cocoons

BACKGROUND: Declining immune function poses an important clinical challenge worldwide and supplementation with natural products that possessing immune enhancing properties is a promising approach for preventing or delaying immune function decline. Cocoons from yellow silkworms are a significant source of lutein, and this unexplored silk extract could be a viable alternative source for dietary lutein. This study assessed immunomodulatory activities of the silk lutein extract. Female BALB/c mice orally received lutein, either as silk or marigold extracts (10 or 20 mg/kg daily), or vehicle only (1% tween 80 in PBS pH 7.4) for 4 weeks. Natural killer (NK) cell activity, specific antibody production, lymphocyte subpopulations, mitogen-induced lymphocyte proliferation, and cytokine production were examined. RESULTS: Silk lutein extract increased NK cell activity, and the effect was dose-related whereas marigold lutein extract was ineffective. Silk lutein extract dose-dependently enhanced antibody production in pre-immunized mice but marigold lutein extract had no effect. Feeding with silk lutein extract increased the populations of CD3+ and CD4 + CD3 + cells. Silk lutein extract also stimulated concanavalin A- and lipopolysaccharide-induced proliferations of T and B lymphocytes, respectively. Moreover, silk lutein extract increased IL-2 and IFN-γ production while the effect of marigold lutein extract was undetectable. CONCLUSIONS: Together, silk lutein extract enhanced both innate and adaptive immune functions. This preparation may prove to be an effective supplement for strengthened immunity.

Thermostability of heterophile antibodies from human sera infected with Schistosoma mansoni and geo-helminths. an immuno-metric statistical analysis

Foram investigados anticorpos de soro humano que provocam lise de eritrócitos de carneiro em ensaios hemolíticos. O presente estudo mostra que a presença de anticorpos citolíticos termoestáveis contra hemácias de carneiro é dependente da infecção por Schistosoma mansoni e é mais freqüente em adultos do que em crianças. A característica termo estável da hemolisina em soros normais não é dependente da presença de Ascaris lumbricoides, Trichuris trichiura ou ancilostomídeos. Além disto, anticorpos heterófilos hemolíticos termo estáveis ativadores de complemento foram demonstrados em crianças com associação de altas cargas de ovos de S. mansoni. Os resultados foram obtidos usando-se os testes z- e o qui quadrado. O teste z- nos permite formular uma alternativa "one side", isto é, a tendência de um dos atributos. Por outro lado o teste do qui quadrado analisa a independência entre atributos usando-se uma tabela de contingência. Ao lado dos interessantes resultados obtidos no campo da esquistossomose mansoni, a abordagem estatística pode apontar novos caminhos para o tratamento de dados na ciência médica.

On the correct determination of reference values for serum antibodies against pigeon serum antigen using a group of healthy blood donors

An ensymatic immunoassay was developed in order to evaluate the statistical distribution of IgG serum antibodies against pooled pigeon ser antigen in 102 healthy blood donors (HBD). A non-normal distribution was obtained as demonstrated by abnormal values of skewness (2.02) and kurtosis (6.50). A cut-off point (0.120) was determined from the mean plus 2 standard derivations of the optical density values obtained in the HBD group. This value was able to segregate 94 percent of subjects. However, when calculation of the mean less 2 SD was performed to delimit 95 percent of the samples, an aberrant negative value was obtained. In contrast, when the nonparametric method of percentile calculation was applied, an optical density value of 0.130 discriminated 97.5 percent of samples. In addition, the interval between p97.5 and p2.5 delimited 95 percent of samples. We conclude that when reference values and cut-off point are determined from an enzymatic immunoassay, careful analysis of the statistical distribution of reference values is necesary in order to avoid the inappropiated in this study for antibodies against pigeon serum antigens

Avaliaçäo de anticorpos naturais humanos (xeno-anticorpos) contra linfócitos de porco / Evaluation of human antibodies (xeno-antibodies) against porcine lymphocytes

A presença de anticorpos naturais contra células de porco (xeno-anticorpos) foi analisada em soros de indivíduos normais e de pacientes imunossuprimidos, imunodeficientes primários e renais crônicos hiperimunizados. Em indivíduos normais a média dos títulos observada foi de 1:664. Em 80,9 por cento de pacientes renais transplantados nao foi observado reduçao do título dos xeno-anticorpos após um ano de imunossupressao. Nos pacientes imunodeficientes foi observado um título mais reduzido, mas nunca inferior a 1:1. Após a eliminaçao dos anticorpos naturais do soro de pacientes renais crônicos hipersensibilizados com antígenos HLA, pela adsorçao dos soros com eritrócitos de porco seguido do tratamento com dithiotreitol (DTT), foi observado que os anticorpos IgG anti-HLA nao reagem com os antígenos de histocompatibilidade das células do porco. As conclusoes deste trabalho foram: o título dos xeno-anticorpos em indivíduos normais é muito elevado; a imunossupressao utilizada nos transplantes renais nao permite reduçao da barreira de anticorpos naturais; os imunodeficientes com títulos muito baixos destes anticorpos talvez possam usufruir de transplantes xenogênicos; o método de eliminaçao "in vitro" dos xeno-anticorpos é reproduzível; os soros dos pacientes renais crônicos hiperimunizados com antígenos HLA, nao reagem cruzadamente com linfócitos de porco.