Protection against Toxoplasma gondii cysts in pigs immunized with rROP2 plus Iscomatrix / Proteção contra cistos de Toxoplasma gondii em suínos imunizados com rROP2 associado à Iscomatrix

Abstract This study aimed to evaluate the humoral immune response in pigs immunized intranasally and intramuscularly with recombinant Toxoplasma gondii rROP2 protein in combination with the adjuvant Iscomatrix. Twelve mixed breed pigs divided into three groups (n=4) were used, G1 received recombinant ROP2 proteins (200 µg/dose) plus Iscomatrix, G2 received PBS plus Iscomatrix, and G3 as the control group. The intranasal (IN) and intramuscular (IM) routes were used. Animals were challenged orally with VEG strain oocysts and treated on day three after challenge. Fever, anorexia, and prostration were the clinical signs observed in all animals. All the G1 animals produced antibodies above the cut-off on the day of the challenge, while the G2 and G3 remained below the cut-off. Better partial protection against parasitemia and cyst tissue formation was observed in G1 than G3. The protection factors against tissue cyst formation were 40.0% and 6.1% for G1 and G2, respectively, compared to G3. In conclusion, there were not systemic antibody responses in pigs with IN immunization with rROP2+Iscomatrix; however, after IM immunization, those animals produced higher titers than animal controls. We associated these results with partial protection obtained against parasitemia and tissue cysts formation.

Resumo O objetivo deste estudo foi avaliar a resposta imune humoral em suínos imunizados pelas vias intranasal e intramuscular com proteínas recombinantes rROP2 do Toxoplasma gondii associadas ao adjuvante Iscomatrix. Doze suínos cruzados divididos em 3 grupos (n=4) foram utilizados. O G1 recebeu proteína recombinante ROP2 (200mg/dose) associada ao adjuvante Iscomatrix; o G2 recebeu PBS associado ao Iscomatrix; e o G3 foi o grupo controle. As vias intranasal (IN) e intramuscular (IM) foram utilizadas. Os animais foram desafiados por via oral com a cepa VEG e tratados no dia três após o desafio. Febre, anorexia e prostração foram os sinais clínicos observados em todos os animais. Todos os animais do G1 produziram anticorpos acima do ponto de corte no dia do desafio, enquanto os animais do G2 e G3 permaneceram abaixo do ponto de corte no desafio. Proteção parcial contra parasitemia e formação de cistos teciduais foram observadas nos suínos do G1 comparados ao G3. Os fatores de proteção contra a formação de cistos teciduais foram 40,0% e 6,1% no G1 e G2, respectivamente, comparados com o G3. Como conclusão, não houve estimulação da resposta imune humoral sistêmica nos suínos após as imunizações IN com rROP2+Iscomatrix. Estes animais, porém, após a imunização IM, produziram títulos de anticorpos mais altos que os animais controles. Esses resultados foram associados a uma proteção parcial contra a parasitemia e formação de cistos teciduais.

rROP2 from Toxoplasma gondii as a potential vaccine against oocyst shedding in domestic cats / rROP2 de Toxoplasma gondii como potencial vacina contra a eliminação de oocistos em gatos domésticos

Abstract The aim of the present study was to evaluate oocyst shedding in cats immunized by nasal route with T. gondii proteins ROP2. Twelve short hair cats (Felis catus) were divided in three groups G1, G2 and G3 (n=4). Animals from G1 received 100 μg of rROP2 proteins plus 20 μg of Quil-A, G2 received 100 μg of BSA plus 20 μg of Quil-A, and the G3 only saline solution (control group). All treatments were done by intranasal route at days 0, 21, 42, and 63. The challenge was performed in all groups on day 70 with ≅ 800 tissue cysts of ME-49 strain by oral route. Animals from G1 shed less oocysts (86.7%) than control groups. ELISA was used to detect anti-rROP2 IgG and IgA, however, there were no correlation between number of oocyst shedding by either IgG or IgA antibody levels. In the present work, in spite of lesser oocysts production in immunized group than control groups, it was not possible to associate the use of rROP2 via nostrils with protection against oocyst shedding. For the future, the use of either other recombinant proteins or DNA vaccine, in combination with rROP2 could be tested to try improving the efficacy of this kind of vaccine.

Resumo O objetivo do presente estudo foi avaliar a eliminação de oocistos de Toxoplasma gondii em gatos imunizados pela via nasal com proteínas ROP2 de T. gondii. Doze gatos sem raça definida (Felis catus) foram divididos em três grupos experimentais G1, G2 e G3 (n = 4). Os animais do G1 receberam 100 μg de proteínas de rROP2 mais 20 μg de Quil-A, G2 recebeu 100 μg de albumina de soro bovino (BSA) junto com 20 μg de Quil-A, e o G3 recebeu apenas solução salina (grupo de controle). Todos os tratamentos foram realizados pela via intranasal nos dias 0, 21, 42 e 63. O desafio foi realizado em todos os grupos no dia 70 com aproximadamente 800 cistos de tecido da cepa ME-49 por via oral. Os animais de todos os grupos tiveram as suas fezes examinadas e o número de oocistos foi determinado durante 20 dias após o desafio. Os animais de G1 eliminaram menos oocistos (86,7%) do que os grupos controles. O ELISA foi utilizado para detectar IgG e IgA anti-rROP2, no entanto, não houve correlação entre o número de eliminhação de oocistos com os níveis de anticorpos IgG ou IgA. No presente trabalho, apesar da menor produção de oocistos no grupo imunizado (G1) em relação aos grupos controles (G2 e G3), não foi possível associar o uso de rROP2 pela via nasal com proteção contra eliminação de oocistos de T. gondii. Para o futuro, a utilização de outras proteínas recombinantes, ou mesmo vacina de DNA, em combinação com rROP2 poderia ser utilizada para tentar melhorar a eficácia deste tipo de vacina.

Evaluation of a recombinant rhoptry protein 2 enzyme-linked immunoassay for the diagnosis of toxoplasmosis acquired during pregnancy

The aim of this study was to evaluate an enzyme-linked immunoassay with recombinant rhoptry protein 2 (ELISA-rROP2) for its ability to detectToxoplasma gondii ROP2-specific IgG in samples from pregnant women. The study included 236 samples that were divided into groups according to serological screening profiles for toxoplasmosis: unexposed (n = 65), probable acute infection (n = 48), possible acute infection (n = 58) and exposed to the parasite (n = 65). When an indirect immunofluorescence assay forT. gondii-specific IgG was considered as a reference test, the ELISA-rROP2 had a sensitivity of 61.8%, specificity of 62.8%, predictive positive value of 76.6% and predictive negative value of 45.4% (p = 0.0002). The ELISA-rROP2 reacted with 62.5% of the samples from pregnant women with probable acute infection and 40% of the samples from pregnant women with previous exposure (p = 0.0180). Seropositivity was observed in 50/57 (87.7%) pregnant women with possible infection. The results underscored that T. gondii rROP2 is recognised by specific IgG antibodies in both the acute and chronic phases of toxoplasmosis acquired during pregnancy. However, the sensitivity of the ELISA-rROP2 was higher in the pregnant women with probable and possible acute infections and IgM reactivity.

Associação de hipovitaminose D com Lúpus Eritematoso Sistêmico e inflamação / Association of hypovitaminosis D with Systemic Lupus Erythematosus and inflammation

Introdução: Atualmente, é descrita elevada prevalência de hipovitaminose D no Lúpus Eritematoso Sistêmico (LES), a qual se associa a algumas manifestações clínicas e maior atividade inflamatória. Objetivo: Avaliar a associação entre insuficiência de vitamina D com LES e marcadores inflamatórios. Métodos: Estudo transversal, tendo sido avaliados 45 pacientes com LES e 24 controles sem a doença. Níveis de 25-hidroxivitamina D [25(OH)D] menores que 30 ng/mL foram considerados insuficientes. A atividade da doença foi avaliada pelo Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Foram avaliados, ainda, proteína C reativa ultrassensível (PCRus) e interleucina-6 (IL-6) para verificação do status inflamatório. Para avaliação do envolvimento renal, foram realizados análise de elementos anormais e sedimentoscopia urinárias (EAS), hematúria e piúria quantitativas, proteinúria e depuração de creatinina em urina de 24 horas e anti-DNA de dupla hélice sérico. Resultados: A prevalência de insuficiência de 25(OH)D foi de 55% nos pacientes lúpicos e 8% nos participantes controles (p = 0,001). A mediana da 25(OH)D foi menor nos pacientes do que no grupo controle. Os pacientes com insuficiência de 25(OH)D apresentaram níveis mais elevados de IL-6 e maior prevalência de hematúria ao EAS. Não houve correlação entre vitamina D, nefrite lúpica e SLEDAI. Conclusão: Em nosso estudo, a insuficiência de vitamina D foi mais prevalente em pacientes com LES e se associou com níveis mais elevados de IL-6 e presença de hematúria. .

Introduction: Nowadays it is described a high prevalence of hypovitaminosis D in Systemic Lupus Erythematosus (SLE), which is associated with some clinical manifestations and increased inflammatory activity. Objective: To evaluate the association between vitamin D insufficiency with SLE and inflammatory markers. Methods: Cross-sectional study, in which have been evaluated 45 SLE patients and 24 controls without the disease. Levels of 25-hydroxyvitamin D [25(OH) D] less than 30 ng/mL were considered inadequate. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). High sensitivity C reactive protein (hsCRP) and interleukin-6 (IL-6) were evaluated for verification of the inflammatory status. For assessment of renal involvement, analysis of abnormal elements and urinay sediment (AES), quantitative hematuria and pyuria, proteinuria and creatinine clearance in 24-hour urine and serum anti-double stranded DNA were performed. Results: The prevalence of 25(OH)D insufficiency was 55% in SLE patients and 8% in the controls participants (p = 0.001). The median of 25(OH)D was lower in patients than in controls. Patients with insufficient 25(OH)D had higher levels of IL-6 and higher prevalence of hematuria in the AES. There was no correlation between vitamin D and SLEDAI or lupus nephritis. Conclusion: In our study, vitamin D deficiency was more prevalent in patients with SLE and was associated with higher levels of IL-6 and hematuria. .

Immunohistochemical expression of vascular endothelial growth factor receptors FIt1 and KDR in the endometrium during the estrus cycle in albino rats

Angiogenesis is an important process in endometrial development and embryonic implantation and is regulated through vascular endothelial growth factor [VEGF]; its receptors Flt1 and KDR. This work aimed to study the immunoexpression of VEGF receptors [VEGF-Rs] in the endometrium at different ages and reproductive phases and correlate them with the histological profiles in these phases. Seventy female albino rats were included in this study. They were divided into seven groups of 10 rats each: one group consisted of rats in the prepubertal period at age 4-6 weeks; five groups consisted of rats in the reproductive period at age 6-10 months, which were divided according to estrus cycle phases into proestrus, estrus, metestrus, diestrus, and pregnant groups; and the sixth group consisted of rats in the postmenopausal period at age 15-18 months. The uteri of all rats were removed and processed for staining with H and E and were subjected to immunohistochemical staining for Flt1 and KDR. For morphometric measurements, uterine wall thickness and Flt1 and KDR optical density in the endometrial surface epithelium, glandular epithelium, stromal cells, and endometrial endothelial cells were measured using image analysis. Results were statistically compared. The expression of VEGF-Rs was highest in the pubertal age group with marked expression of these receptors in the proestrus phase followed by the estrus phase. This supports the role of sex hormones, especially the estrogen hormone, in regulating VEGF-R expression. The Flt1 receptor was predominantly expressed in endometrial and stromal cells as well as in blastocysts, whereas the KDR receptor was predominantly expressed in endometrial endothelial cells. Comparison among all groups and then between each two groups revealed statistically significant differences in the measured morphometric parameters. The upregulation of Flt1 and KDR could be involved in the regulation of endometrial endothelial cell proliferation and in increase in endometrial vascular permeability, especially at implantation sites

Overexpression of Fc receptor-like 1 associated with B-cell activation during hepatitis B virus infection

The role of B cells in the pathogenesis of hepatitis B virus (HBV) infection has not been explored in depth. In the present study, the activation status of B cells from peripheral blood of healthy controls (N = 20) and patients with acute hepatitis B (AHB, N = 15) or chronic hepatitis B (CHB, N = 30) was evaluated by measuring the expression levels of B-cell activation markers CD69 and CD86, using quantitative real-time PCR and flow cytometry. Moreover, the potential mechanism underlying B-cell activation during HBV infection was further investigated by analyzing the expression profile of FCRL1, an intrinsic activation molecule of B cells. An elevation in the levels of B-cell activation markers including CD69 and CD86 was observed in the AHB patients (44.31 ± 9.27, 27.64 ± 9.26%) compared to CHB patients (30.35 ± 11.27, 18.41 ± 6.56%, P < 0.05), which was still higher than healthy controls (12.23 ± 7.84, 8.22 ± 3.43%, P < 0.05). Furthermore, the expression of FCRL1 was found to be similar to B-cell activation markers, which was highest in AHB patients (70.15 ± 17.11%), lowest in healthy donors (36.32 ± 9.98%, P < 0.05) and half-way between these levels in patients with CHB (55.17 ± 12.03%, P < 0.05). The results were positively associated with aberrant B-cell activation. These data suggest that B cells can play a role in HBV infection, and therefore more effort should be devoted to exploring their functions.

The expanding spectrum of clinically-distinctive, immunotherapy-responsive autoimmune encephalopathies / O espectro em expansão das encefalopatias autoimunes clinicamente distintas e que respondem à imunoterapia

The autoimmune encephalopathies are a group of conditions that are associated with autoantibodies against surface neuronal proteins, which are likely to mediate the disease. They are established as a frequent cause of encephalitis. Characteristic clinical features in individual patients often allow the specificity of the underlying antibody to be confidently predicted. Antibodies against the VGKC-complex, mainly LGI1(leucine-rich glioma-inactivated 1), CASPR2 (contactin-associated protein 2), and contactin-2, and NMDA (N-methyl, D-aspartate) -receptor are the most frequently established serological associations. In the minority of cases, an underlying tumour can be responsible. Early administration of immunotherapies, and tumour removal, where it is relevant, offer the greatest chance of improvement. Prolonged courses of immunotherapies may be required, and clinical improvements often correlate well with the antibody levels. In the present article, we have summarised recent developments in the clinical and laboratory findings within this rapidly expanding field.

As encefalopatias autoimunes constituem um grupo de condições associadas à presença, no soro, de anticorpos contra proteínas de superfície neuronais. Acredita-se que esses anticorpos sejam mediadores da ocorrência da doença, sendo reconhecidos atualmente como causas frequentes de encefalite. Apresentações clínicas características permitem, muitas vezes, predizer o grupo específico de anticorpos subjacentes. Anticorpos contra o complexo VGKF, especialmente LGI1 (leucine-rich glioma-inactivated1), CASPR2 (contactin-associated protein 2) e contactina-2, e contra o receptor NMDA(N-methyl, D-aspartate) são as associações sorológicas mais frequentemente estabelecidas. Na minoria dos casos, pode ser detectado um tumor subjacente. As maiores chances de melhora estão relacionadas à administração precoce de imunoterapia e à remoção do tumor, quando presente. A duração da imunoterapia pode se prolongada e a melhora se correlaciona, muitas vezes, com os níveis séricos de anticorpos. Neste artigo, estão resumidos os avanços recentes nos achados clínicos e laboratoriais neste campo que está em tão rápida expansão.

Toxoplasma gondii: humoral and cellular immune response of BALB/c mice immunized via intranasal route with rTgROP2 / Toxoplasma gondii: avaliação da resposta imune humoral e celular de camundongos BALB/c imunizados pela via nasal com rTgROP2

TgROP2 is an intracellular protein associated with rhoptries of Toxoplama gondii and an antigen component of a candidate vaccine for toxoplasmosis. The purpose of the present study was to evaluate the efficacy of rTgROP2 to stimulate humoral and cellular immune responses in BALB/c mice via intranasal injection. TgROP2 partial coding sequence was (196-561) amplified by PCR from genomic T. gondii RH strain DNA and cloned into the pTrcHis expression vector. Escherichia coli Rosetta 2 cells transformed with pTrcHis-TgROP2 showed high levels (~1 mg.mL-1) of recombinant protein after 4 hours of IPTG induction. Recombinant TgROP2 exhibited an apparent Mr equal to 54 kDa. In order to test immunogenicity of the recombinant protein, 10 BALB/c mice received 10 µg of rROP2 protein + 10 µg of Quil-A via intranasal injection. Doses were administered at days 0, 21, and 42. Three animals were euthanized and used to evaluate cell-ular immune response on day 62. Five (50 percent) and two (20 percent) out of ten animals produced IgG (DO mean = 0.307; cut-off = 0.240) and IgA (DO mean = 0.133, cut-off = 0.101), respectively, by ELISA on day 62. The proliferation of splenocytes revealed high stimulation index (SI) when co-cultured with 5, 10 and 15 µg.mL-1 of rTgROP2. These results indicate that intranasal immunization with recombinant protein ROP2 plus Quil-A can elicit both cellular and humoral immune responses in BALB/c mice.

TgROP2 é uma proteína localizada nas roptrias do Toxoplasma gondii, sendo um antígeno candidato a componente de uma vacina contra a toxoplasmose. O objetivo do presente estudo foi avaliar a eficácia da TgROP2 recombinante em estimular a resposta imune celular e humoral de camundongos BALB/c após estímulo intranasal. A sequência da TgROP2 foi amplificada pela PCR a partir da cepa RH e clonada em vetor de expressão pTrc-His. Após a transformação em Escherichia coli- Rosetta 2, a pTrcHis-TgROP2 exibiu alto nível de expressão após 4 horas de indução com IPTG. A proteína recombinante apresentou uma massa molecular aparente de aproximadamente 54 kDa. Para avaliar a imunogenicidade dessa proteína recombinante, 10 camundongos receberam, pela via intranasal, 10 µg da rROP2 associado a 10 µg de Quil-A. Três doses foram realizadas nos dias 0, 21 e 42. No dia 62 do experimento, três animais foram eutanasiados para avaliar as respostas imune celular e humoral. Cinco (50 por cento) e dois (20 por cento) dos 10 animais apresentaram níveis de IgG (DO média = 0,307; ponto de corte = 0,240) e IgA (DO média = 0,133; ponto de corte = 0,101) acima do ponto de corte no ELISA no dia 62. A proliferação de esplenócitos revelou altos Índices de Estimulação (SI), quando as células foram cultivadas com 5, 10 e 15 µg.mL-1 de rTgROP2. Os resultados obtidos indicam que a via nasal pode estimular tanto a resposta imune celular como a humoral.

[Expression of a recombinant serine-rich Entamoeba Histolytica protein [SREHP]]

Entamoeba histolytica antigenic markers such as Serine-Rich E. histolytica protein [SREHP] have recently been used for vaccine preparation, genetic diversity studies of Entamoeba histolytica isolates and for differentiation between E. histolytica and E. dispar species. This study was carried out with the aim of expression of a recombinant Serine Rich E. histolytica protein in the laboratory to use it in the ELISA kit. In this study which is an exploration method, an Iranian isolate of Serine-Rich E. histolytica gene which had previously been cloned in bluescript plasmid [pBSc], was cut using BamHI restriction enzyme. After extracting and purification from gel, the SREHP gene was sub cloned into pET32a expression vector. The inserted gene was confirmed with Rosconis solution, PCR and sequencing methods. PCR was performed with the SREHP specific primers as well as pET T7 promoter primer. The cloned gene was also digested with HindIII and BamHI restriction enzymes. Recombinant plasmid was conveyed to competent cell BL21 [DE3]. A colony of the plasmid including SREHP gene was cultivated and induced with IPTG. The result of expressed protein was observed on the SDS-PAGE gel. The SREHP gene was sub cloned into pET32a expression vector. A recombinant plasmid including an inserted SREHP gene was screened and confirmed with quick check method using Ruscoins solution, as well as PCR by special primers [SREHP and universal pET primer], digested with BamHI and HindIII restriction enzymes. Finally an open reading frame of 666 nucleotides from inserted SREHP gene was obtained with the sequencing method. The recombinant protein of Serine-Rich E. histolytica in presence of IPTG was expressed in five hours and the result of expressed protein in the length of 44 KDa was observed on SDS-PAGE gel. SREHP protein was successfully cloned and expressed in this study. However additional studies are recommended for preparation and purification of the SREHP in a large quantity and the using it for the ELISA test

Toxoplasma gondii: cloning, sequencing, expression, and antigenic characterization of ROP2, GRA5 and GRA7

Toxoplasma gondii is an intracellular obligate protozoan, which infects humans and warm-blooded animals. The aim of the present study was to clone the rop2, gra5 and gra7 genes from T. gondii RH strain and to produce recombinant proteins. The rop2, gra5 and gra7 gene fragments produced by polymerase chain reaction were cloned into the pET102/D-TOPO® vector which contains thioredoxin and polyhistidine tags at the C- and N-ends, respectively, and is expressed in Escherichia coli BL21(DE-3). The expression fusion proteins were found almost entirely in the insoluble form in the cell lysate. These recombinant proteins were purified with an Ni-NTA column. Concentrations of the recombinant antigens produced in the E. coli BL21-star ranged from 300 to 500 μg/ml growth media, which was used to immunize rabbits. We observed an identity ranging from 96 to 97% when nucleotide sequences were compared to GenBank database sequences. Immunocharacterization of proteins was made by indirect immunofluorescence assay. These proteins will be used for serodiagnosis and vaccination.

Immunological, cellular and molecular events in typhoid fever.

Salmonella, a facultative intracellular Gram-negative bacterium infects a wide range of hosts causing several gastrointestinal diseases and enteric fever in humans and certain animal species. Typhoid caused by Salmonella typhi remains a major health concern in India and worldwide. Also, with emergence of multidrug resistant strains, Salmonella has acquired increased virulence, communicability and survivability, resulting in increased morbidity and mortality. Though a number of vaccines for typhoid are available against S. typhi (or also against S. typhimurium), these have certain undesirable side effects and the search for new immunogens suitable for vaccine formulation is still continuing. The immune response to primary Salmonella infection involves both humoral and cell-mediated responses. The protective immunity against Salmonella depends on host- parasite interaction, however; the detailed mechanism of virulence, innate resistance and susceptibility of host remains unclear. This review focuses on the molecular, immunological and cellular mechanisms of pathogenesis of Salmonella infection to provide an insight to counteract bacterial infections and allow a better understanding of its clinical manifestations. It also reviews better technological possibilities combined with increased knowledge in related fields such as immunology and molecular biology and allow for new vaccination strategies. Some new approaches such as subunit and nucleic acid vaccines and recombinant antigen which are becoming increasingly important for the development of potential vaccines have also been discussed. A significant progress has been made in our understanding of Salmonella pathogenesis. Despite these efforts, however, many challenges exist, especially for investigators who aim to understand how the pathogenic mechanisms operating in vitro apply to in vivo model systems. However, unyielding work and collaborations between Salmonella researchers and clinicians worldwide have made significant contributions to understanding the interaction between virulence determinants and immunity required to stop the spread of this pathogen.

Cloning, sequencing, expression, and antigenic characterization of rMSP4 from Anaplasma marginale isolated from Paraná State, Brazil

Anaplasmosis is a bovine intraerythrocytic disease caused by the bacterium Anaplasma marginale; it causes significant economic losses in tropical and subtropical regions, worldwide. The msp4 gene of an A. marginale strain isolated in Paraná, Brazil, was amplified by PCR and sequenced; its cloning into the pET102/D-TOPO® vector produced an msp4-6xHis-V5-HP thioredoxin fusion gene construct. This recombinantclone was over-expressed in Escherichia coli BL21(DE-3); the expressed fusion protein was found almost entirely in the insoluble form (inclusion bodies) in the cell lysate. The inclusion bodies were solubilized with urea and the recombinant protein was purified by Ni-NTA column and dialyzed. This method produced a relatively high yield of rMSP4, which was used to immunize rabbits. The deduced amino acid sequence encoded by MSP4 showed 99% homology to A. marginale isolates from Florida, USA, and from Minas Gerais, Brazil. Both rMSP4 and native MSP4 were recognized by post- immunization rabbit serum, showing that rMSP4 has conserved epitopes. As antigenicity was preserved, rMSP4 might be useful for the development of vaccine against anaplasmosis.

CD99 activates T cells via a costimulatory function that promotes raft association of TCR complex and tyrosine phosphorylation of TCR zeta

We investigated the co-stimulatory role of a cell-surface protein, CD99. Co-ligation of CD99 and suboptimal CD3 induced T-cell activation to a level comparable to that obtained with optimal CD3 or CD3+CD28. We also noted concomitant enhancement of the earliest T-cell receptor (TCR) signaling events. In addition, co-ligation of CD99 and CD3 led to translocation of TCR complexes into the lipid raft, without concomitant migration of CD99 to the raft, and consequent enhancement of TCR zeta-mediated signal 1. These data demonstrate the unique properties of CD99 co-stimulation that distinguish this molecule from CD28 and other raft-resident co-stimulatory factors.

Protective immunity induced with 23 kDa membrane protein dna vaccine of Schistosoma japonicum Chinese strain in infected C57BL/6 mice.

A 23 kDa membrane protein DNA vaccine for Schistosoma japonicum Chinese strain was developed and tested for its protective efficacy and immune responses in infected C57BL/6 mice. The cDNA encoding SjC23 amplified from pUC19-SjC23 were subcloned into an eukaryotic expression vector (pcDNA3.1). Forty-eight female C57BL/6 mice were divided into three groups. Each mouse of group A (control group) was immunized intramuscularly (i.m.) with 100 microg of pcDNA3.1; of group B (SjC23 group) was immunized (i.m.) with 100 microg of pcDNA3.1-SjC23; of group C (SjC23+IL-12) was immunized (i.m.) with a mixture of 100 microg of pcDNA3.1-SjC23, 100 microg of pcDNA3.1-p35 and 100 microg of pcDNA-p40. These were followed by two boosts of the same DNA once every two weeks. All mice were challenged with 45 cercariae of Schistosoma japonicum Chinese strain at week 8, and were killed and perfused at week 14. The numbers of recovered worms and hepatic eggs were counted. The expression of SjC23 and p35, p40 in muscle tissue was determined by immunohistochemical method. By culture of spleen cells, the production of IL-2, IL-4, IL-10 and IFN-gamma with the stimulation of specific antigen of the recombinant hydrophilic domain of SjC23 (rSjC23-HD) was determined after the last immunization (before challenge). Sera were collected from each group before immunization and two weeks before and after challenge. Anti-SjC23 antibodies were tested by Western blot. The results showed that SjC23 and p35, p40 of mouse IL-12 were expressed on the membrane and in the plasma of the muscle cells of immunized C57BL/6 mice. A rise of IL-2 and IFN-gamma in the SjC23 group and SjC23+IL-12 group was observed; No changes were found in IL-4 and IL-10. Detection of anti-SjC23 antibody with Western blot showed that after the third immunization (before challenge) all the serum samples from the control group were negative; 8 of 10 sera from the SjC23 group and 9 of 10 sera from the SjC23+IL-12 group were positive. The worm reduction rates in the SjC23 group and SjC23+IL-12 group were 26.9% and 35.4% respectively; the liver eggs reduction rates were 22.2% and 28.4%, respectively in comparison to the control group. This indicates that the pcDNA3.1-SjC23 DNA vaccine can induce partial protection against Schistosoma japonicum infection in C57BL/6 mice.

Vaccination of different strains of mice against cutaneous leishmaniosis: Usefulnes of membrane antigens encapsulated into liposomes by intraperitoneal and subcutaneous administration

The objetive of this study was to assess the usefulness of parasite-surfase molecules reconstituted into liposomes to vaccinate four diffeent strains of mice (C57BL/10, CBA/ca, C57BL/6 and NZB) with different levels of susceptibility to L. m. mexicana infection and to find out possible increases in specific antibody response after vaccination. but before infection with virulent promastigotes. Mice were vaccinated with parasite membrane antigens incorporated into liposomes and antibody levels were recorded. Vaccination was effective to protect CBA/ca and C57BL/6 but not C57BL/10 mice and NZB animals were naturally resistant. Intraperitoneal (ip) was more efective than the subcutaneus (sc) route if inoculation, and the induction of disease-resistance correlated with the production of IgG anti-Leishmania in CBA/ca, C57BL/6 and C57BL/10 mice

Mycoplasma in the spotlight of AIDS: partial biochemical characterization of mycoplasma-derived components inducing TNF alpha secretion and blast transformation.

We have previously demonstrated that the AIDS-associated Mycoplasma fermentans as well as Mycoplasma capricolum membranes activated bone marrow macrophages to secrete tumor necrosis factor alpha (TNF alpha) and induce blast transformation of splenic lymphocytes. Herein, we show that the membrane component of Mycoplasma capricolum capable of inducing TNF alpha secretion is a hydrophobic protein. This is supported by our findings that the TNF alpha inducing activity was eluted by a phenyl-Sepharose column in a peak distinct from bulk membrane lipids. The hydrophobic nature of the protein is indicated by the activity of the "hydrophobic protein" fraction of the membranes, and the pattern of elution obtained by the phenyl-Sepharose column. Fractionation of the M. capricolum membranes, solubilized by CHAPS (3-[(3-cholamidopropyl)-dimethylammoniol]1-propane sulfate) on a gel filtration column revealed a major peak of TNF alpha inducing activity of about 75,000 daltons, and a minor peak of about 55,000 daltons. The mitogenic activity, though spread throughout the column, peaked in the same fractions as the TNF alpha inducing activity. Both activities co-eluted by the phenyl-Sepharose column as well. However, the mitogenic activity of the membranes was much more resistant to elevated temperatures and extreme pH treatment.

Vitelline envelope formation during oogenesis in Bufo arenarum

The formation of vitelline envelope (VE) during the oogenesis of Bufo arenarum (Amphibia Anura) is described. At the stage of early vitellogenesis, the first structures appear: the number of oocyte microvilli increases, and many cross sections of them are observed between the follicle cells and the oocyte. A filamentous material is observed inside the follicle cells and between the follicle cells and the oocyte. Multivesicular bodies are also found in the follicle cells, and in the perivitelline space. The micrographs also suggest the participation of the oocyte in the process of VE formation: large vesicles are present in the cortex of the oocyte, filled with an amorphous material of low and uniform electron density. Some of them are in the process of releasing their content to the perivitelline space. Many vesicles (probably resulting from microvilli fragmentation) are also observed in the perivitelline space. During late vitellogenesis the VE is a continuous structure between the layer of follicle cells and the oocyte. The filamentous material is aggregated in bundles, forming a net, and the spherical components are now either included in the orifices of the net, or free near the oocyte's surface. At the end of oogenesis, when the VE is completely formed, it is difficult to distinguish its components independently. Immunolocalization with antibodies against VE, show a positive reaction in follicle cells and oocytes in previtellogenic and full grown ovarian follicles. This analysis suggests that both the oocyte and the follicle cells are directly involved in the synthesis and secretion of the components of the vitelline envelope in Bufo arenarum.

A conserved epitope on nuclear pore phosphoproteins reflects cell division status.

The nuclear pore complexes mediate the selective nuclear import of proteins in a signal- and energy-dependent process. We have earlier reported the characterization of a monoclonal antibody, Mab E2, that recognizes a novel class of nuclear pore phosphoproteins involved in signal-binding and protein transport. In the present study, we have analyzed the pattern of immunoreactivity of Mab E2 in cultured rat fibroblasts and have observed significant differences in the expression of epitopes in proliferating and quiescent cells. Furthermore, the common epitope recognized by Mab E2 is conserved across species, consistent with its essential role in nuclear protein import.

Aspects of immunity for the AMA-1 family of molecules in humans and non-human primates malarias

The apical membrane antigen (AMA-1) family of malaria merozoite proteins is characterised by a high degree of inter-species conservation. Evidence that the protein (PK66/AMA-1) from the simian parasite Plasmodium knowlesi was protective in rhesus monkeys suggested that the 83kDa P. falciparum equivalent (PF83/AMA-1) should be investigated for protective effects in humans. Here we briefly review pertinent comparative data, and describe the use of an eukaryotic full length recombinant PF83/AMA-1 molecule to develop a sensitive ELISA for the determination of serological responses in endemic populations. The assay has revealed surprisingly high levels of humoral response to this quantitatively minor antigen. We also show that PK66/AMA-1 inhibitory mAb's are active against merozoites subsequent to release from schizont-infected red cells, further implicating AMA-1 molecules in red cell invasion.