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A M Ruiz

Publications and source records attributed to A M Ruiz.

At least 37 records · Page 2Linked to original sources
PubMed1993

Isolation and characterization of a gene from Trypanosoma cruzi encoding a 46-kilodalton protein with homology to human and rat tyrosine aminotransferase.

The complete sequence of a gene encoding a 46-kDa protein of Trypanosoma cruzi is presented. The first ATG complies with the consensus sequence for initiation of translation. A single band of 2 kb was highlighted by hybridizing a probe from the 46-kDa protein gene to a Northern filter containing total T. cruzi RNA. The gene is present in 50-80 copies per cell and most of them are contained in 2 tandem arrays on large T. cruzi chromosomes (> 2000 kb). A strong homology with rat and human tyrosine aminotransferase was detected. Homology with a Trypanosoma brucei retrotransposon was found in the nonsense strand of the intergenic region.

Amino Acid Sequence↗
PubMed1991

Trypanosoma cruzi: cellular and antibody response against the parasite in mice immunized with a 19-amino acid synthetic peptide.

Several monoclonal antibodies were prepared against the flagellar fraction of Trypanosoma cruzi epimastigotes (Tulahuén strain, stock Tul 2). One of them, FCH-F8-4, has previously shown biologic activity against the parasite (complement-mediated lysis and neutralization of the trypomastigote infectivity). Immunopurified antigens using this monoclonal antibody elicited a protective immune response in mice. Two recombinant cDNA clones were detected with this anti-flagellar fraction monoclonal antibody on a lambda gt11 expression library prepared from T. cruzi epimastigote mRNA. The insert of one of these cDNA clones, lambda(FCH-F8-4)1 (150 bp) coded for a 19-amino acid peptide (PAFLGCSSRFSGSFSGVEP). This insert hybridized with a 5.0-kb mRNA from epimastigotes. The beta-galactosidase fusion protein was produced in lysogenic bacteria. The monoclonal antibody recognized the epitope present in the fusion protein after western blotting of the crude lysate. A synthetic peptide (SP4) containing the complete sequence of lambda(FCH-F8-4)1 was constructed on solid phase. This peptide was able to inhibit the ELISA reactivity (in a range from 13 to 52%) of flagellar fraction immunized mouse sera and when administered (coupled to KLH or alone) to BALB/c mice with Bordetella pertussis as adjuvant, it induced a humoral and cellular immune response which was detected by ELISA, immunofluorescence, blotting, and DTH reactions against T. cruzi antigens. The immune response obtained indicates that this synthetic peptide resembles the parasite antigen conformation and could be useful for diagnosis purposes or be able to elicit immunoprotection against T. cruzi infection.

Amino Acid Sequence↗
PubMed1990

Monoclonal antibodies against the flagellar fraction of epimastigotes of Trypanosoma cruzi: immunoprotection against metacyclic trypomastigotes obtained by immunization of mice with an affinity-purified antigen.

Subcellular fractions of Trypanosoma cruzi (epimastigotes) were assayed in their capacity to induce protective or aggressive effects in experimental animals. The flagellar fraction showed the best immunoprotective properties without tissular aggression. Monoclonal antibodies were prepared from mice immunized with this fraction. One of them, FCH-F8-4, was able to neutralize the infectivity of bloodstream trypomastigotes, to produce complement-mediated lysis on cell culture-derived trypomastigotes and to recognize the surface of trypomastigotes and epimastigotes by immunofluorescence. FCH-F8-4 reacted in Western blotting with several epimastigote proteins ranging from 50 to 150 kDa, showing a more intense reactivity with 4 bands while it reacted with two molecules on trypomastigote preparations (15 and 48 kDa). Purified antibody was coupled to CNBr-activated Sepharose and used to purify antigens from epimastigote extracts. These antigens were used to immunize BALB/c mice in the presence of Bordetella pertussis as adjuvant. Animals were protected against a challenge with 10(3) metacyclic forms of T. cruzi (Tulahuén strain). Only 40% of immunized mice presented detectable parasites in blood after challenge. Parasitemia decreased 90% in relation to controls in those animals. Survival of immunized mice was 100% in all immunoprotection experiments. These results suggest that the epitope recognized by FCH-F8-4 present in the purified antigens keeps the protective characteristics of flagellar fraction and could be a candidate for the development of a vaccine against T. cruzi infection.

Animals↗
PubMed1989

Further antigenic characterization of porcine rotavirus YM.

We recently reported that the serotype specificity of YM, a group A porcine rotavirus, is different from those of the previously established rotavirus serotypes, 1 to 6 (A. M. Ruiz, I. V. Lopez, S. Lopez, R. T. Espejo, and C. F. Arias, J. Virol. 62:4331-4336, 1988). Here we demonstrate by cross-neutralization studies that rotavirus YM is also antigenically distinct from prototype rotavirus strains of serotypes 7 (Ty1), 8 (69M), 9 (WI61), and 10 (B223). A comparison of the serotype-determining amino acid regions of the YM surface glycoprotein, VP7, with the reported homologous sequences of rotavirus strains Gottfried, 69M, B37, F45, and WI61 further supported the serotypic individuality of the rotavirus YM VP7 protein.

Amino Acid Sequence↗
PubMed1989

Identification of major Trypanosoma cruzi antigenic determinants in chronic Chagas' heart disease.

To identify Trypanosoma cruzi target antigens in overt Chagas' heart disease, a parasite lambda gt11 cDNA library was screened with the serum of a patient with a severe chagasic heart involvement (JL). Using a phage dot array immunoassay, 5 highly antigenic clones, JL1, JL5, JL7, JL8, and JL9, were probed with sera from clinically characterized T. cruzi infected subjects. The correlation of cloned T. cruzi antigen recognition with the clinical status of the subjects led to the identification of a recombinant antigen, JL5, that reacted predominantly with sera from patients with Chagas' heart disease. The antigenic determinant of the JL5 recombinant was a small 35 amino acid peptide. The nucleotide and the deduced amino acid sequence, together with other experimental data, allowed identification as the C-terminal portion of a T. cruzi P ribosomal protein. The C-terminal undecapeptide in JL5, EDDDMGFGLFD, was highly homologous to the same region of the human P protein SD(D/E)DMGFGLFD. The latter sequence has been identified as the P protein epitope in systemic lupus erythematosus (SLE). Positive SLE sera reacted with the JL5 recombinant phage, suggesting that the T. cruzi P protein might induce antibodies with a similar specificity to that of P antibodies in SLE.

Adult↗
PubMed1989

[Molecular and immunologic bases for the development of a vaccine against Chagas disease].

Subcellular fractions of T. cruzi epimastigotes (Epi) were studied for their capability to induce protective or aggressive effects in animals. The flagellar fraction (F) showed the best immunoprotective properties without tissular aggression. Monoclonal antibodies were raised against F. Two of them, FCH-F8-1 and 4, were able to neutralize the infectivity of bloodstream forms, to mediate lysis by complement of cell culture derived[trypomastigotes (Tripo) and to recognize the surface of Tripo and Epi. FCH-F8-1 reacted with a 85 kDa protein from Tripo (assayed by immunoprecipitation) and with peptides of 43 kDa on Epi and Tripo (tested by immunoblotting). FCH-F8-4 recognized several proteins ranging from 50 to 150 kDa on Epi and two molecules of 15 and 48 kDa on Tripo. Mice immunized with antigens purified by affinity chromatography by using FCH-F8-4 were protected against the infection. Several recombinant clones were detected on a cDNA lambda gt11 expression library constructed from T. cruzi Epi (Tulahuén strain): three with FCH-F8-4 and two with FCH-F8-1. One clone recognized by each monoclonal antibody was studied gamma (FCH-F8-1) 1 and gamma (FCH-F8-4) 1. Both inserts were of 150 base pairs each; they detected a 3.5 and 5.0 kilobases Epi mRNA, respectively. Both inserts were sequenced, and the amino acid sequences were inferred. gamma (FCH-F8-4) 1 codified for a 19 aa peptide, PAFLGCSSRFSGSFSGVEP, and gamma (FCH-F8-1) 1 for a 29 aa peptide EFLERGRISCORHSYTSYTSCSDEHNVTPFC. The whole 19 aa peptide was synthesized. This peptide (SP4) inhibited the ELISA reactivity against the parasite of chronically infected and F immunized mouse sera.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Dynamics of transmission of Trypanosoma cruzi in a rural area of Argentina. IV. Serologic, parasitologic and electrocardiographic study of the human population.

A serologic and electrocardiographic study was carried out in people living in 18 households in La Invernada (LI), Departamento Figueroa, and in 20 houses in Amamá (A), Departamento Moreno, both in the province of Santiago del Estero, Argentina. Serological tests performed were indirect hemagglutination (IHAT) and indirect immunofluorescence antibody tests (IFAT). Complement fixation, direct agglutination and ELISA tests were also done for those sera, showing discordant results for either IHAT or IFAT. All people in LI and children up to 12 years old in A were studied by xenodiagnosis. Approximately 50% of the whole population was infected (50% in LI and 50.9% in A) and a similar prevalence rate was already recorded in children below 10 years. A moderate increase of infection rates was observed in successively older age groups, indicating that most of the people became infected in the first decade of life. Comparison of serological profiles of both populations suggests a protective effect of insecticidal control campaigns in those individuals born between 1961 and 1971. New surveys carried out in both populations 2 years later rendered a 4 times greater annual incidence rate in A as compared with LI (7.9% vs 1.8% respectively). No differences were found in the percentages of abnormal electrocardiograms among seropositive and seronegative individuals from both settlements. The prevalence of complete right bundle branch block (RBBB) was higher in seropositive than in seronegative people (4.8% vs 2.3%) but lower than those figures recorded for other parts of the country and the continent. This suggests that in spite of its high prevalence, Chagas' disease has low morbidity in both localities.

Adolescent↗
PubMed1988

Molecular and antigenic characterization of porcine rotavirus YM, a possible new rotavirus serotype.

In 1983, we isolated a porcine rotavirus (strain YM) that was prevalent in several regions of Mexico, as judged by the frequency of its characteristic electropherotype. By a focus reduction neutralization test, rotavirus YM was clearly distinguished from prototype rotavirus strains belonging to serotypes 1 (Wa), 2 (S2), 3 (SA11), 4 (ST3), 5 (OSU), and 6 (NCDV). Minor, one-way cross-neutralization (1 to 5%) was observed when antisera to the various rotavirus strains were incubated with rotavirus YM. In addition, the YM virus was not neutralized by neutralizing monoclonal antibodies with specificity to serotypes 1, 2, 3, and 5. The subgroup of the virus was determined to be I by enzyme-linked immunosorbent assay. To characterize the serotype-specific glycoprotein of the virus at the molecular level, we cloned and sequenced the gene coding for VP7. Comparison of the deduced amino acid sequence with reported homologous sequences from human and animal rotavirus strains belonging to six different serotypes further supported the distinct immunological identity of the YM VP7 protein.

Amino Acid Sequence↗
PubMed1986

Monoclonal antibodies against the flagellar fraction of epimastigotes of Trypanosoma cruzi: complement-mediated lytic activity against trypomastigotes and passive immunoprotection in mice.

Trypanosoma cruzi, the causative agent of Chagas' disease, is widely spread in Central and South America. The present report describes three monoclonal antibodies (mAbs) directed against the flagellar fraction of epimastigotes (Ffe) of the parasite, Tulahuén strain. The three mAbs were of IgG1 isotype. Indirect immunofluorescence assays revealed that the three mAbs bind to epimastigotes, the FCH-F8-1 and -3 bind to blood trypomastigotes (BT) and FCH-F8-1 is the only one that binds to amastigotes. Three different proteins of the parasite were recognized by the mAbs in immunoprecipitation assays: an 85 kDa of BT with the FCH-F8-1 mAb, a 40 kDa of Ffe with the FCH-F8-2 mAb, and a 90 kDa of Ffe and of BT with the FCH-F8-3 mAb. Positive complement mediated lysis (CML) of BT and metacyclic forms, obtained from the insect vector feces, were shown by the FCH-F8-1, while FCH-F8-3 only showed CML against the metacyclic trypomastigotes. FCH-F8-2 did not mediate any CML activity. Passive transference of the mAbs to BALB/c mice conferred protection, in terms of survival, ranging from 50 (FCH-F8-2 and -3) to 80% (FCH-F8-1) against a challenge with 1 X 10(3) BT. These results suggest that FCH-F8-1 may be a useful tool to purify proteins in order to investigate their role in immunoprotection experiments.

Animals↗
PubMed1986

Immunoprotection of mice against Trypanosoma cruzi with a lyophilized flagellar fraction of the parasite plus adjuvant.

The immunization with the flagellar (F) fraction from epimastigotes of Trypanosoma cruzi has been shown to protect mice against a challenge of bloodstream trypomastigotes of the parasite, both in terms of mortality and decrease in parasitemia. We have compared the immunoprotective properties of the fresh F fraction with those of a lyophilized F (LF) fraction, alone or together with Bordetella pertussis (Bp) as adjuvant. The best results were obtained with LF + Bp: after challenge with 1 X 10(3) metacyclic trypomastigotes, 100% of the mice immunized with LF + Bp survived, and 60% of them showed no signs of parasitemia. Only the animals in which patent parasitemia was demonstrated presented heart and muscle infiltrates.

Adjuvants, Immunologic↗
PubMed1985

Protective immunity and pathology induced by inoculation of mice with different subcellular fractions of Trypanosoma cruzi.

Mice were immunized with subcellular fractions obtained by differential centrifugation from epimastigotes of Trypanosoma cruzi (Tulahuén strain). In a chronic model of Chagas' disease, they were challenged each with 25 bloodstream trypomastigotes. Non-immunized, non-challenged and non-immunized challenged animals were kept as controls. Among the challenged mice, those immunized with 105,000 g pellet (Mc) and 105,000 g supernatant (Cs) fractions presented positive xenodiagnosis, myocarditis and myositis similar to those shown by non-immunized challenged controls. The fractions enriched in flagella, the 5000 g pellet (P5) and the flagellar fraction (F) resulted in fewer animals with positive xenodiagnosis and in hosts partially protected from the development of myocarditis. In the absence of infection, Mc and Cs induced an intense myocarditis while F induced mild lesions similar to those found in the controls. P5 caused a myocarditis intermediate between that elicited by Mc and that in the controls. 50% of the animals immunized with Cs presented pathological electrocardiograms in the absence of challenge. The animals immunized with F and P5 and challenged were protected against the development of pathological electrocardiograms, whereas those immunized with Mc and Cs behaved like the non-immunized controls. The immunized, non-challenged animals presented anti-T. cruzi IgG antibodies, with titres which were lower than those shown by the immunized and challenged mice.--The results show the possibility of obtaining tissue lesions with antigenic preparations of T. cruzi in the absence of infection, and suggest that the mechanisms involved in the generation of myocarditis and electrocardiographic alterations are probably different, since these pathologies can be elicited by different subcellular fractions. Among the antigenic components of the parasite, the flagellar fraction gave the best immunoprotective properties, with little or no immunoaggressive effects.

Animals↗
PubMedDate not supplied

Inhibition of trypomastigotes' infectivity by a monoclonal antibody directed to a glycoconjugated fraction of epimastigotes of Trypanosoma cruzi.

In this work it was shown that the infectivity of trypomastigote forms of Trypanosoma cruzi was affected upon the interaction with the Monoclonal Antibody (McAb) 2E9, which was raised against a glycoconjugated fraction of membranes of epimastigotes (Tulahuen strain). Characterization of the epitope recognized by this McAb, as well as its effects on complement mediated lysis and host cell invasion are reported. Immunocytochemical analysis showed that the McAb was reactive with two macromolecules (41-58 kDa) present on Trypanosoma cruzi epimastigotes (Tulahuen and Y strain), while it recognized several trypomastigotes macromolecules, showing a more intense reactivity with a band of 80 kDa. By indirect immunofluorescence, it was found there were subpopulations of blood and tissue culture derived trypomastigotes which attach the antibody to varying degrees. Studies using chemical or enzymatically treated antigens suggested that the McAb 2E9 was directed against carbohydrate epitopes, which were identified as being--galactosyl residues. In addition, preliminary results are shown, suggesting that the epitope recognized by the McAb 2E9 is involved in adhesion/or internalization of trypomastigotes.

Animals↗