Immunoanalysis of different antigenic preparations of Angiostrongylus cantonensis for neuroangiostrongyliasis diagnosis improvement

BACKGROUND Angiostrongylus cantonensis is the etiological agent of neuroangiostrongyliasis in humans, which is developed in gastropods and vertebrate species, mainly rodents. Human transmission occurs through consumption of molluscs and paratenic hosts infected with L3, and the migration of larvae to the central nervous system causes eosinophilic meningitis. Laboratory diagnosis is based on molecular and immunological tests, using young or adult females as a source of antigens. However, these tests give positive results only after several weeks of symptoms onset and also cross-reactions with others parasite infections may occur. OBJECTIVES The purpose of this work was to study different antigenic preparations of distinct evolutionary phases of A. cantonensis, in order to improve serological techniques for disease immunodiagnosis. METHODS For this purpose, antigenic fractions of different evolutionary forms were evaluated by Dot-enzyme-linked immunosorbent assay (Dot-ELISA) and Western blot using serum samples. FINDINGS All analysed fractions showed reactivity with serum samples from patients with neuroangiostrongyliasis, especially female membrane alkaline (FAM) and female soluble alkaline (FAS) fractions together with female soluble saline (FSS), improving the technique specificity. MAIN CONCLUSIONS The results point to the possibility of use of raw female antigens in association with alkaline membrane antigens extracted from adult worms to aid in diagnosis and helps initiate neuroangiostrongyliasis surveillance and control actions.

Genetic diversity of Trypanosoma cruzi strains isolated from chronic chagasic patients and non-human hosts in the state of São Paulo, Brazil

BACKGROUND Trypanosoma cruzi shows an exuberant genetic diversity. Currently, seven phylogenetic lineages, called discrete typing units (DTUs), are recognised: TcI-TcVI and Tcbat. Despite advances in studies on T. cruzi and its populations, there is no consensus regarding its heterogeneity. OBJECTIVES This study aimed to perform molecular characterisation of T. cruzi strains, isolated in the state of São Paulo, to identify the DTUs involved and evaluate their genetic diversity. METHODS T. cruzi strains were isolated from biological samples of chronic chagasic patients, marsupials and triatomines through culture techniques and subjected to molecular characterisation using the fluorescent fragment length barcoding (FFLB) technique. Subsequently, the results were correlated with complementary information to enable better discrimination between the identified DTUs. FINDINGS It was possible to identify TcI in two humans and two triatomines; TcII/VI in 19 humans, two marsupials and one triatomine; and TcIII in one human host, an individual that also presented a result for TcI, which indicated the possibility of a mixed infection. Regarding the strains characterised by the TcII/VI profile, the correlation with complementary information allowed to suggest that, in general, these parasite populations indeed correspond to the TcII genotype. MAIN CONCLUSIONS The TcII/VI profile, associated with domestic cycles and patients with chronic Chagas disease, was the most prevalent among the identified DTUs. Furthermore, the correlation of the study results with complementary information made it possible to suggest that TcII is the predominant lineage of this work.

Persistent cutaneous canine leishmaniasis caused by Leishmania (Viannia) braziliensis in an area with predominance of Nyssomyia neivai in the state of São Paulo, Brazil / Leishmaniose cutânea canina persistente causada por Leishmania (Viannia) braziliensis em uma área com predomínio de Nyssomyia neivai no estado de São Paulo, Brasil

Abstract American cutaneous leishmaniasis (ACL) is a neglected zoonotic disease caused mainly by Leishmania (Viannia) braziliensis, which is endemic throughout Brazil. Canine ACL cases were investigated in a rural area of Monte Mor, São Paulo, where a human ACL case had been confirmed. Dogs were evaluated through clinical and laboratory diagnosis including serology, cytological tissue preparations and PCR on skin lesions, lymph node and bone marrow samples. Entomological investigations on sandflies trapped in the surroundings of the study area were performed for 14 months. Nyssomyia neivai was the predominant phlebotomine species, comprising 94.65% of the captured specimens (832 out of 879). This species was the most abundant in all trapping sites, including human homes and dog shelters. Ny. whitmani, Migonemyia migonei, Pintomyia monticola, Evandromyia cortellezzii, Pi. fischeri and Expapilata firmatoi were also captured. Two of the three dogs examined were positive for anti-Leishmania IgG in ELISA using the antigen Fucose mannose ligand and skin samples were positive for L. (V.) braziliensis in PCR, but all the samples collected were negative for L. (L.) infantum. One of the dogs had a confirmed persistent infection for more than one year.

Resumo A leishmaniose tegumentar Americana (LTA) é uma doença zoonótica negligenciada, causada principalmente por Leishmania (Viannia) braziliensis, sendo endêmica em todo o Brasil. Foram investigados casos de LTA canina em uma área rural da cidade de Monte Mor, São Paulo, onde foi confirmado um caso humano de LTA. Os cães foram avaliados por diagnóstico clínico e laboratorial, incluindo sorologia, esfregaços microscópicos e PCR de amostras em lesões de pele, linfonodos e medula óssea. Também foram realizadas investigações entomológicas durante 14 meses, usando-se armadilhas luminosas para flebotomíneos nas proximidades da área de estudo. Nyssomyia neivai foi a espécie de flebotomíneo predominante com 94,65% dos espécimes capturados (832 de 879). Essa espécie foi a mais abundante em todos os locais de captura, incluindo-se abrigos para humanos e cães. Foram também capturadas as espécies Ny. whitmani, Migonemyia migonei, Pintomyia monticola, Evandromyia cortellezzii, Pi. fischeri e Expapilata firmatoi. Dos três cães examinados, dois apresentaram IgG anti-Leishmania positivo no ELISA, usando-se o antígeno "Fucose mannose ligand", PCR da lesão de pele positivo para L. (V.) braziliensis e negativo em todas amostras para L. (L.) infantum. Um dos cães apresentou infecção persistente por mais de um ano.

Fragment detection of coleopteran and triatomine insects in experimentally contaminated acai pulp and sugarcane juice

INTRODUCTION: Oral transmission of acute Chagas disease is an emerging public health concern. This study aimed to detect insect fragments in experimentally contaminated food, by comparing triatomines with other insects. METHODS: Food samples were experimentally contaminated with insects, processed to recover their fragments by light filth, and analyzed by microscopy and Polymerase Chain Reaction (PCR). RESULTS: Morphological differences between coleopteran and triatomine insects were observed in microscopic images. PCR was efficient in amplifying Triatominae DNA in the experimentally contaminated food. CONCLUSIONS: This methodology could be utilized by food analysts to identify possible insect contamination in food samples. (AU)

Molecular diagnosis of symptomatic toxoplasmosis: a 9-year retrospective and prospective study in a referral laboratory in São Paulo, Brazil

ABSTRACT Symptomatic forms of toxoplasmosis are a serious public health problem and occur in around 10-20% of the infected people. Aiming to improve the molecular diagnosis of symptomatic toxoplasmosis in Brazilian patients, this study evaluated the performance of real time PCR testing two primer sets (B1 and REP-529) in detecting Toxoplasma gondii DNA. The methodology was assayed in 807 clinical samples with known clinical diagnosis, ELISA, and conventional PCR results in a 9-year period. All samples were from patients with clinical suspicion of several features of toxoplasmosis. According to the minimum detection limit curve (in CT), REP-529 had greater sensitivity to detect T. gondii DNA than B1. Both primer sets were retrospectively evaluated using 515 DNA from different clinical samples. The 122 patients without toxoplasmosis provided high specificity (REP-529, 99.2% and B1, 100%). From the 393 samples with positive ELISA, 146 had clinical diagnosis of toxoplasmosis and positive conventional PCR. REP-529 and B1 sensitivities were 95.9% and 83.6%, respectively. Comparison of REP-529 and B1 performances was further analyzed prospectively in 292 samples. Thus, from a total of 807 DNA analyzed, 217 (26.89%) had positive PCR with, at least one primer set and symptomatic toxoplasmosis confirmed by clinical diagnosis. REP-529 was positive in 97.23%, whereas B1 amplified only 78.80%. After comparing several samples in a Brazilian referral laboratory, this study concluded that REP-529 primer set had better performance than B1 one. These observations were based after using cases with defined clinical diagnosis, ELISA, and conventional PCR.

Detection of Leishmania (Viannia) braziliensis by PCR in samples collected by scraping the lesion edges from patients of an endemic area

American cutaneous leishmaniasis (ACL) is an infectious disease caused by Leishmania. Their diagnosis is performed in samples collected from the lesion biopsies, which has to be performedby physicians. For simplifying the sample collection, this study proposes a minimally invasive procedure, by scraping the lesion edges. Laboratory diagnosis by PCR was performed and compared with the microscopic examination, by analyzing 28 samples collected from patients with suspicion of ACL. Sample collected from the lesion edge with a sterile toothpick was divided into two aliquots. One aliquot was analyzed under direct microscopy, and the second by PCR, by using two primer pairs (one for Leishmania genus and other for L. (V.) braziliensis). Of 28 samples, 27 (96.43 %) showed concordant results in both methodologies (eight positive and 20 negative). The PCR methodologyis an invaluable tool: (i) to determine the Leishmania species; (ii) to provide an alternative procedure of sample collection, when an authorized professional is not available in the respective health service;and (iii) to propose a minimally invasive procedure for collecting biological material...

Ocular toxoplasmosis with positive polymerase chain reaction in peripheral blood ­ report of two cases, São Paulo State, Brazil / Toxoplasmose ocular com reação em cadeia da polimerase positiva em sangue periférico ­ relato de dois casos, estado de São Paulo, Brasil

Aims: To describe the use of polymerase chain reaction (PCR) in peripheral blood and demonstrate its importance in the clinical follow-up of patients with ocular toxoplasmosis. Case description: Two immunocompetent patients were clinically diagnosed with acute ocular toxoplasmosis. The routine clinical evaluation consisted of fundus examination using binocular indirect ophthalmoscopy, color fundus photography, fluorescein angiography, and spectral domain optical coherence tomography. The serological diagnosis was made by enzyme-linked immunosorbent assay (ELISA) and confirmed by enzyme-linked fluorescent assay (ELFA). The molecular diagnosis was made by PCR in peripheral blood using the B1 gene of Toxoplasma gondii as marker. The younger patient was male, had previous lesion in the right eye, complained of low visual acuity in the left eye and was under treatment. The older patient was male, had retinal detachment, and presented with sudden loss of acuity in the right eye. The fundus examination revealed chorioretinal scar in the left eye. IgG was reactive, IgM was non-reactive, and PCR was positive in the peripheral blood of both patients. New blood samples were collected for serological and molecular monitoring and PCR remained positive in both cases. Six weeks after treatment with oral sulfadiazine and pyrimethamine, the PCR yielded negative results. Conclusion: The results show that T. gondii antigens may be found in peripheral blood during ocular reactivations and that PCR may be a good tool for the follow-up of patients with ocular toxoplasmosis.

Objetivos: Descrever o uso da reação em cadeia da polimerase (PCR) no sangue periférico e demonstrar sua importância no acompanhamento clínico de pacientes com toxoplasmose ocular. Descrição dos casos: Dois pacientes imunocompetentes foram clinicamente diagnosticados com toxoplasmose ocular aguda. Rotineiramente, a avaliação clínica foi feita por fundoscopia com o uso de oftalmoscópio binocular indireto, retinografia colorida, angiografia fluorescente e tomografia de coerência óptica espectral. A sorologia foi realizada por ensaio imunoenzimático (ELISA) e confirmada por ensaio imunoenzimático fluorescente ELFA (IgG, IgM). O diagnóstico molecular foi realizado por PCR em sangue periférico usando o gene B1 de Toxoplasma gondii como marcador. O paciente mais jovem era do sexo masculino, apresentava lesão prévia no olho direito, queixa de baixa acuidade visual no olho esquerdo e estava sob tratamento. O paciente mais velho era do sexo masculino, apresentava descolamento de retina e súbita diminuição de visão no olho direito. A fundoscopia revelou cicatriz coriorretiniana no olho esquerdo. Ambos os pacientes tinham IgG reagente, IgM não reagente e PCR positivo em sangue periférico. Novas amostras de sangue foram coletadas para monitoramento sorológico e molecular e a PCR permaneceu positiva em ambos os casos. Seis semanas após o início do tratamento com sulfadiazina e pirimetamina oral, os resultados do PCR tornaram-se negativos. Conclusões: Os resultados mostram que antígenos de T. gondii podem ser encontrados em sangue periférico durante as reativações oculares e que a PCR parece ser uma boa ferramenta para o acompanhamento de pacientes com toxoplasmose ocular.

GENOTYPE CHARACTERIZATION OF Leishmania (Viannia) braziliensis ISOLATED FROM HUMAN AND CANINE BIOPSIES WITH AMERICAN CUTANEOUS LEISHMANIASIS / Caracterização genotípica de isolados de Leishmania (Viannia) braziliensis provenientes de biopsias de humanos e cães com leishmaniose tegumentar americana

Introduction: American tegumentary leishmaniasis (ATL) can be caused by Leishmania (Viannia) braziliensis complex. The evolution of ATL initially results in lesions and can develop into disseminated or diffuse forms. The genetic diversity of L. (V.) braziliensis in some endemic areas of Brazil has been poorly studied, such as in the state of São Paulo. This study analyzed the genetic diversity of L. (V.) braziliensis isolates collected from patients and dogs with LTA from the state of São Paulo. Methods: Leishmaniasis diagnosis was determined by PCR. The 132 biopsies were collected in different regions of Sao Paulo State, Brazil (36 municipalities). The genetic characterization of L. (V.) braziliensis isolates was tested by RFLP-PCR using DNA extracted from biopsies. The primer set amplified a specific region of Leishmania internal transcribed spacers of the ribosomal DNA locus. Results: Of the 132 samples, 52 (40%) were completely genotyped by RFLP-PCR (44 from human patients and eight from dogs). The results showed nine distinct patterns. The majority of the genotyped samples were from Sorocaba (30), and the others were distributed among 14 other municipalities. The first pattern was more frequent (29 samples), followed by pattern 2 (nine samples) and pattern 3 (three samples). Patterns 4, 6, 7, 8 and 9 were composed of two samples each and pattern 5 of one sample. Conclusion: These results suggest that polymorphic strains of L. (V.) braziliensis circulate in the state of São Paulo. These data agree with studies from other regions of Brazil, showing great variability among the natural populations of endemic foci. .

Introdução: A leishmaniose tegumentar americana (LTA) é causada pelo sub-gênero Leishmania (Viannia) braziliensis. A evolução da LTA resulta com a evolução das lesões iniciais. A diversidade genética de L. (V.) braziliensis em algumas áreas endêmicas brasileiras, como no estado de São Paulo, é pouco conhecida. Assim, este estudo teve como objetivo analisar a variabilidade genética de isolados de L. (V.) braziliensis coletados de biopsias de pacientes e cães com LTA no estado de São Paulo. Métodos: O diagnóstico da leishmaniose foi realizado por PCR. As 132 biópsias analisadas foram coletadas em diferentes regiões do Estado de São Paulo, Brasil (36 municípios). A caracterização genética de L. (V.) braziliensis foi realizada por RFLP-PCR utilizando DNA extraído das biopsias. O conjunto de iniciadores utilizado amplificou a região ITS de Leishmania. Resultados: Das 132 amostras analisadas, 52 (40%) foram completamente genotipadas por RFLP-PCR (44 de pacientes e oito de cães). Os resultados mostraram nove padrões distintos. A maioria das amostras genotipadas foi de Sorocaba (30), e as demais foram distribuídas entre 14 outros municípios. O primeiro padrão foi mais frequente (29 amostras), seguido pelo padrão 2 (nove amostras), padrão 3 (três amostras). Padrões 4, 6, 7, 8 e 9 foram compostos de duas amostras de cada um e o padrão 5, com uma amostra. Conclusão: Estes resultados sugerem que cepas polimórficas de L. (V.) braziliensis circulam no estado de São Paulo. Estes dados são concordantes com estudos em outras regiões do Brasil, mostrando grande variabilidade destas populações naturais de focos endêmicos. .

Molecular diagnosis of cryptococcal meningitis in cerebrospinal fluid: comparison of primer sets for Cryptococcus neoformans and Cryptococcus gattii species complex

Aim: This study evaluated the use of polymerase chain reaction for cryptococcal meningitis diagnosis in clinical samples. Materials and methods: The sensitivity and specificity of the methodology were evaluated using eight Cryptococcus neoformans/C. gattii species complex reference strains and 165 cere- brospinal fluid samples from patients with neurological diseases divided into two groups: 96 patients with cryptococcal meningitis and AIDS; and 69 patients with other neurological opportunistic diseases (CRL/AIDS). Two primer sets were tested (CN4-CN5 and the multiplex CNa70S-CNa70A/CNb49S-CNb-49A that amplify a specific product for C. neoformans and another for C. gattii). Results: CN4-CN5 primer set was positive in all Cryptococcus standard strains and in 94.8% in DNA samples from cryptococcal meningitis and AIDS group. With the multiplex, no 448-bp product of C. gattii was observed in the clinical samples of either group. The 695 bp products of C. neoformans were observed only in 64.6% of the cryptococcal meningitis and AIDS group. This primer set was negative for two standard strains. The specificity based on the negative samples from the CTL/AIDS group was 98.5% in both primer sets. Conclusions: These data suggest that the CN4/CN5 primer set was highly sensitive for the identification of C. neoformans/C. gattii species complex in cerebrospinal fluid samples from patients with clinical suspicion of cryptococcal meningitis. .

Anti-Toxoplasma gondii antibodies in pregnant women and their newborn infants in the region of São José do Rio Preto, São Paulo, Brazil / Anticorpos anti-Toxoplasma gondii em gestantes e seus neonatos na região de São José do Rio Preto, São Paulo, Brazil

CONTEXT AND OBJECTIVE: Toxoplasmosis transmission during pregnancy can cause severe sequelae in fetuses and newborns. Maternal antibodies may be indicators of risk or immunity. The aim here was to evaluate seropositivity for anti-Toxoplasma gondii (anti-T. gondii) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies and IgG avidity in pregnant women and their newborn infants. DESIGN AND SETTING: Cross-sectional study in a high-risk pregnancy outpatient clinic. METHODS: Serum samples from pregnant women (n = 87) and their respective newborns (n = 87) were evaluated for anti-T. gondii antibodies using indirect immunofluorescence (IIF) (IgM and IgG), enzyme-linked immunosorbent assay (ELISA) (IgG) and an avidity test. RESULTS: Anti-T. gondii antibodies were identified in 64.4 percent of the serum samples from the mothers and their infants (56/87). Except for two maternal serum samples (2.3 percent), all others were negative for anti-T. gondii IgM antibodies, using IIF. The results showed that 92.9 percent of the pregnant women had high IgG avidity indexes (> 30 percent) and four samples had avidity indexes between 16 and 30 percent. Two women in the third trimester of pregnancy were positive for anti-T. gondii IgM antibodies; their babies had avidity indexes between 16 and 30 percent. The avidity indexes of serum from the other 83 newborns were similar to the results from their mothers. CONCLUSIONS: The results showed that 2 percent of the pregnant women were at risk of T. gondii transmission during the gestational period. These data seem to reflect the real situation of gestational toxoplasmosis in the northwestern region of the state of São Paulo.

CONTEXTO E OBJETIVOS: A toxoplasmose, quando transmitida durante a gestação, pode causar graves sequelas em fetos e neonatos. Anticorpos maternos podem ser indicadores de risco ou de imunidade. O objetivo foi avaliar a positividade dos anticorpos das classes imunoglobulina M (IgM) e imunoglobulina G (IgG) anti-Toxoplasma gondii (anti-T. gondii), bem como a avidez de IgG em gestantes e seus neonatos. TIPO DE ESTUDO E LOCAL: Estudo transversal em ambulatório de gestação de alto risco. MÉTODOS: Anticorpos anti-T. gondii foram avaliados em amostras de soro de gestantes (n = 87) e seus respectivos neonatos (n = 87) com o uso dos métodos imunofluorescência indireta (IFI) (IgM e IgG), ensaio imunoenzimático (ELISA) (IgG) e avidez. RESULTADOS: Anticorpos anti-T. gondii foram identificados em 64,4 por cento das amostras de soro das mães e seus bebês (56/87). Com exceção de duas amostras de soro materno (2,3 por cento), todas as demais foram negativas anticorpos IgM anti-T. gondii determinado pela IFI. Os resultados mostraram que 92,9 por cento das gestantes tinham índices elevados de avidez de IgG (> 30 por cento) e 4 amostras apresentaram índices de avidez entre 16-30 por cento. Duas gestantes no terceiro trimestre da gravidez eram positivas IgM anti-T. gondii; seus bebês apresentaram índices de avidez entre 16 e 30 por cento. Os índices de avidez dos soros dos outros 83 recém-nascidos foram semelhantes àqueles encontrados nas amostras maternas. CONCLUSÕES: Os resultados mostraram que 2 por cento das gestantes estavam sob risco de transmissão de T. gondii durante o período gestacional. Estes dados parecem refletir a real situação da toxoplasmose gestacional na região noroeste do Estado de São Paulo.

Molecular diagnosis of cerebral toxoplasmosis: comparing markers that determine Toxoplasma gondii by PCR in peripheral blood from HIV-infected patients

As cerebral toxoplasmosis is the most common cerebral focal lesion in AIDS patients, this study evaluated three PCR markers for diagnosis, since some limitations remain present, such as low parasite levels in some clinical samples. The molecular markers were B22-B23 and Tg1-Tg2 (based on the B1 gene) and Tox4-Tox5 (non-coding fragment, repeated 200-300-fold). DNA samples from 102 AIDS patients with previously known diagnosis were analyzed. The cerebral toxoplasmosis group was constituted of DNA extracted from the blood of 66 AIDS patients, which was collected before or until the third day of the therapy for toxoplasmosis. DNA from the blood of 36 AIDS patients with other neurologic opportunistic infections was used as control group. Sensitivities of B22-B23, Tg1-Tg2, and Tox4-Tox5 markers were of 95.5 percent, 93.9 percent, and 89.3 percent, respectively. In the control group, the specificities were of 97.2 percent (B22-B23), 88.9 percent (Tg1-Tg2), and 91.7 percent (Tox4-Tox5). The association of at least two markers increased the PCR sensitivity and specificity. The concordance index between two markers varied from 83.3 percent to 93.1 percent. These data demonstrated that all markers evaluated here were highly sensitive for T. gondii determination, although B22-B23 has been shown to be the best. The association of two markers increases PCR sensitivity, but the procedure was more expensive and time-consuming.

Papel da resposta imune à Trans-sialidade na infecção por Trypanosoma cruzi / The role of immune response to Trans-sialidase in Trypanosoma cruzi infection

O primeiro objetivo deste trabalho foi o de determinar as propriedades imunogênicas de uma proteína recombinante que contém o domínio catalítico da trans-sialidase (TS) de Trypanosoma cruzí. Observou-se que a imunizaçao com esta proteína recombinante induziu a formaçao de anticorpos capazes de inibir a atividade enzimática da TS e de linfócitos T específicos. Camundongos A/Sn imunizados com a TS apresentaram uma reduçao significativa na parasitemia e na mortalidade causada pela infecçao aguda por tripomastigotas. Esta imunidade conferida pela imunizaçao com a TS foi revertida pelo tratamento dos animais com anticorpos anti-CD4 ou com inibidores da produçao de óxido nítrico, sugerindo a participaçao destes no controle da parasitemia e mortalidade. A reduçao na parasitemia parece nao ser dependente da presença de anticorpos inibidores da atividade enzimática pois animais imunizados com a enzima desnaturada, nao produzem estes anticorpos e mesmo assim apresentam significativa reduçao na parasitemia. A transferência passiva de anticorpos de animais imunizados com a enzima íntegra também nao reduz a parasitemia, entretanto retarda a mortalidade indicando um papel para os anticorpos específicos na fase tardia da infecçao aguda. Na segunda parte deste trabalho estudou-se o papel protetor do ácido siálico da superfície dos tripomastigotas contra a açao de anticorpos líticos chagásicos específicos paras resíduos a-Gai (Ch-anti-a-Gai). Observou-se que parasitas sem ácido siálico sao extremamente suscetíveis a açao lítica dos anticorpos Ch-anti-a-Gal quando comparados aos tripomastigotas que contém ácido siáiico na superfície. Esta proteçao, causada pelo ácido siáiico, é dependente da carga negativa exercida por este, pois a adiçao de íons Mg 2+ favorece a açao dos anticorpos Ch-anti-a-Gal. O efeito protetor do ácido siáiico na superfície dos tripomastigotas pode, eventualmente, ser generalizado na açao de outros ligantes e conferir uma vantagem para a sobrevivência dos parasitas, principalmente nos momentos iniciais da infecçao. No soro de indivíduos com doença de Chagas há anticorpos Ch-anti-a-Gai e anticorpos que inibem a atividade TS. Neste caso, foi demonstrado que a inibiçao da adiçao de ácido siálico por anticorpos anti-TS favorecem o efeito aglutinante e citotóxico dos anticorpos Ch-anti-a-Gal