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C Carrillo

Publications and source records attributed to C Carrillo.

At least 37 records · Page 2Linked to original sources
PubMed1998

African swine fever virus NL gene is not required for virus virulence.

Previously, we described a highly conserved nonessential African swine fever virus (ASFV) right variable region gene, NL. Deletion of NL from the European pathogenic isolate E70 resulted in almost complete attenuation of the virus in domestic swine. To study gene function further, NL gene deletion mutants were constructed from two pathogenic African ASFV isolates, Malawi Lil-20/1 (Mal) and Pretoriuskop/96/4 (Pr4). Unexpectedly, both Mal (Mal-deltaNL) and PR4 (Pr4deltaNL) null mutants remained highly virulent when inoculated in swine. Mal-deltaNL exhibited a disease and virulence phenotype indistinguishable from its revertant, Mal-NLR, which caused 100% mortality. Mortality among Pr4deltaNL-infected animals was also high; however, a significant delay in onset of fever and viraemia and in time to death was observed. These data indicate that NL gene function is not required for ASFV virulence and that other yet-to-be identified viral determinants perform significant virulence functions in these African field isolates.

African Swine Fever Virus↗
PubMed1998

In vivo analysis of the stability and fitness of variants recovered from foot-and-mouth disease virus quasispecies.

We have analysed the ability to infect pigs of two foot-and-mouth disease virus (FMDV) variants isolated at low frequencies from virus populations (quasispecies) generated in pigs on infection with a parental virus, C-S8c1. A monoclonal antibody-resistant mutant (MARM21), and a variant isolated at early times post-infection (S-3T1), each exhibiting a unique amino acid substitution in VP1, were able to cause disease in pigs, both by direct inoculation or by contact transmission. The symptoms developed were similar to those produced by C-S8c1 or the related virus C-S15c1. The VP1 sequence of viral RNA directly recovered from lesions of infected animals confirmed the stability of the variant genotypes. Pigs infected with S-3T1 consistently showed an advance of 12 to 24 h in the emergence of fever and lesions when compared to animals infected with C-S8c1 or the remaining variants, an observation consistent with its early isolation. The ability of FMDV variants to compete in vivo with C-S8c1 was investigated in co-infection experiments. Analysis of the proportion of each of the competitors in lesions of co-infected pigs revealed that none of the variants was completely overgrown by the parent. However, co-infection with C-S8c1 and MARM21 resulted in lesions in which C-S8c1 was predominant, indicating a selective disadvantage of this variant in swine. In contrast, lesions from swine co-infected with C-S8c1 and S-3T1 contained similar proportions of the two viruses. These results document fitness variations in vivo among components of the mutant spectrum of FMDV quasispecies.

Animals↗
PubMed1998

Protective immune response to foot-and-mouth disease virus with VP1 expressed in transgenic plants.

It has been reported recently that genes encoding antigens of bacterial and viral pathogens can be expressed in plants in a form in which they retain native immunogenic properties. The structural protein VP1 of foot-and-mouth disease virus (FMDV), which has frequently been shown to contain critical epitopes, has been expressed in different vectors and shown to induce virus-neutralizing antibodies and protection in experimental and natural hosts. Here we report the production of transformed plants (Arabidopsis thaliana) expressing VP1. Mice immunized with leaf plant extracts elicited specific antibody responses to synthetic peptides representing amino acid residues 135 to 160 of VP1, to VP1 itself, and to intact FMDV particles. Additionally, all of the immunized mice were protected against challenge with virulent FMDV. To our knowledge, this is the first study showing protection against a viral disease by immunization with an antigen expressed in a transgenic plant.

Animals↗
PubMed1998

Deletion of a CD2-like gene, 8-DR, from African swine fever virus affects viral infection in domestic swine.

An African swine fever virus (ASFV) gene with similarity to the T-lymphocyte surface antigen CD2 has been found in the pathogenic African isolate Malawi Lil-20/1 (open reading frame [ORF] 8-DR) and a cell culture-adapted European virus, BA71V (ORF EP402R) and has been shown to be responsible for the hemadsorption phenomenon observed for ASFV-infected cells. The structural and functional similarities of the ASFV gene product to CD2, a cellular protein involved in cell-cell adhesion and T-cell-mediated immune responses, suggested a possible role for this gene in tissue tropism and/or immune evasion in the swine host. In this study, we constructed an ASFV 8-DR gene deletion mutant (delta8-DR) and its revertant (8-DR.R) from the Malawi Lil-20/1 isolate to examine gene function in vivo. In vitro, delta8-DR, 8-DR.R, and the parental virus exhibited indistinguishable growth characteristics on primary porcine macrophage cell cultures. In vivo, 8-DR had no obvious effect on viral virulence in domestic pigs; disease onset, disease course, and mortality were similar for the mutant delta8-DR, its revertant 8-DR.R, and the parental virus. Altered viral infection was, however, observed for pigs infected with delta8-DR. A delay in spread to and/or replication of delta8-DR in the draining lymph node, a delay in generalization of infection, and a 100- to 1,000-fold reduction in virus titers in lymphoid tissue and bone marrow were observed. Onset of viremia for delta8-DR-infected animals was significantly delayed (by 2 to 5 days), and mean viremia titers were reduced approximately 10,000-fold at 5 days postinfection and 30- to 100-fold at later times; moreover, unlike in 8-DR.R-infected animals, the viremia was no longer predominantly erythrocyte associated but rather was equally distributed among erythrocyte, leukocyte, and plasma fractions. Mitogen-dependent lymphocyte proliferation of swine peripheral blood mononuclear cells in vitro was reduced by 90 to 95% following infection with 8-DR.R but remained unaltered following infection with delta8-DR, suggesting that 8-DR has immunosuppressive activity in vitro. Together, these results suggest an immunosuppressive role for 8-DR in the swine host which facilitates early events in viral infection. This may be of most significance for ASFV infection of its highly adapted natural host, the warthog.

African Swine Fever↗
PubMed1998

TGF-beta1 up-regulates the mRNA for the Na+/Ca2+ exchanger in neonatal rat cardiac myocytes.

Northern analyses of neonatal cardiac myocytes demonstrated that TGF-beta1 (5 ng/ml) stimulates and IL-1beta (5 ng/ml) decreases the steady-state levels of the mRNA coding for the Na+/Ca2+ exchanger. This is in agreement with the effects of TGF-beta1 and IL-1beta on beating rate and calcium uptake, suggesting that such effects might be mediated, at least partially, through up-regulation of the Na+/Ca2+ exchanger. Basal and TGF-beta1 stimulated mRNA levels were inhibited by the PKC inhibitors H7 (10 microM) and GF109203X (250 nM). In addition, apigenin (12.5 microM), a MAP kinase inhibitor, was able to inhibit basal mRNA levels for the exchanger. Cycloheximide (35.5 microM) had no effect on basal mRNA levels for the exchanger but steady-state levels were diminished in cells treated with TGF-beta1. Finally, actinomycin D (10 microM) inhibited both basal and TGF-beta1 stimulated mRNA levels, though with a more pronounced effect in the presence of TGF-beta1. These results suggest that a complex mechanism of regulation exists for the exchanger and that PKC and possibly MAP kinases might be involved. The up-regulation of this important protein for calcium extrusion, induced by TGF-beta1, might prepare cells to better overcome the calcium overload which occurs under cellular stress and might explain some of the cytoprotective effects of TGF-beta1.

Animals↗
PubMed1997

A BIR motif containing gene of African swine fever virus, 4CL, is nonessential for growth in vitro and viral virulence.

An African swine fever virus (ASFV) gene with similarity to viral and cellular inhibitor of apoptosis genes (iap) has been described in the African isolate Malawi Lil-20/1 (ORF 4CL) and a cell-culture-adapted European virus, BA71V (ORF A224L). The similarity of the ASFV gene to genes involved in inhibiting cellular apoptosis suggested the gene may regulate apoptosis in ASFV-infected cells and thus may function in ASFV virulence and/or host range. Sequence analysis of additional African and European pathogenic isolates demonstrates that this gene is highly conserved among both pig and tick ASFV isolates and that its similarity to iap genes is limited to the presence of a single IAP repeat motif (BIR motif) in the ASFV gene. To study gene function, a 4CL gene deletion mutant, delta 4CL, was constructed from the pathogenic Malawi Lil-20/1 isolate. Growth characteristics of delta 4CL in swine macrophage cell cultures were indistinguishable from those of parental virus. Infected macrophage survival time and the induction and magnitude of apoptosis in virus-infected macrophages were comparable for cells infected with either delta 4CL or parental virus. In infected swine, delta 4CL exhibited an unaltered Malawi Lil-20/1 virulence phenotype. These data indicate that, although highly conserved among ASFV isolates, the 4CL gene is nonessential for growth in macrophage cell cultures in vitro and for pig virulence. Additionally, despite its limited similarity to JAP genes, 4CL exhibits no anti-apoptotic function in infected macrophage cell cultures. The high degree of gene conservation among ASFV isolates, together with the apparent lack of function in the swine host, suggests 4CL may be a host range gene involved in aspects of infection in the arthropod host, ticks of the genus Ornithodoros.

African Swine Fever↗
PubMed1997

RNA editing status of nad7 intron domains in wheat mitochondria.

The most highly conserved structures of group II introns are the helical domains V and VI near the 3'splice site. Within this region of each of the four introns in the wheat mitochondrial nad7 gene encoding NADH dehydrogenase subunit 7, there are A-C mispairs. To determine whether C-to-U type RNA editing restores conventional A-U pairing, we sequenced RT-PCR products from partially-spliced nad7 template RNA and gel-fractionated, excised intron RNA. We examined transcripts from germinating wheat embryos and seedlings because these two stages of development show pronounced differences in steady state levels of nad7 intronic RNAs. We observed editing at only two of the six predicted sites, and they were located at homologous positions within domain V of the third and fourth introns. A third site was found to be edited within the unmodelled domain VI loop of the fourth intron. Similar patterns of RNA editing were seen in wheat embryos and seedlings. These observations, and the presence of other non-conventional base pairs particularly within domain V of plant mitochondrial introns, indicate weaker helical core structure than in ribozymic group II introns. Moreover, the incompleteness or absence of editing in wheat nad7 excised intron RNA suggests that, although editing may contribute to splicing efficiency, it is not essential for splicing.

Base Composition↗
PubMed1997

Duration of the foot-and-mouth disease virus antibody response in mice is closely related to the presence of antigen-specific presenting cells.

Natural and experimental hosts infected with foot-and-mouth disease virus (FMDV) develop a long-lasting immune response that is closely related to the presence of anti-FMDV antibodies (Ab). We show here that spleen cells from animals which had been infected 3 or more months previously induced an anti-FMDV-Ab response in untreated animals which lasted more than 210 days after cell transfer. Persistence of infectious virus was excluded since virus isolation or detection of the viral genome by PCR in donor splenocytes were consistently negative. The role of antigen presentation (AP) in this phenomenon was studied in vivo by using irradiated splenocytes from virus-sensitized donor mice. Although these irradiated cells were unable to induce anti-FMDV-Ab in normal or irradiated recipient mice, they elicited a strong secondary reaction in FMDV-pre-sensitized recipients. The presence of AP cells (APC) presenting FMDV epitopes (FMDV/APC) was also analysed in mice sensitized to FMDV in different ways. A close correlation between FMDV/APC and the presence of anti-FMDV-Ab was found in infected mice as well as in mice immunized with different doses of inactivated virus, with or without adjuvants. Experiments in vivo and in vitro showed that the APC activity can be specifically blocked with either anti-MHC class II monoclonal antibody or anti-FMDV antiserum, and is dependent on the presence of T cell function. These results strongly suggest that persistent FMDV/APC are responsible for the existence and maintenance of an anti-virus immune response regardless of the immunization method used.

Animals↗
PubMed1996

Amino acid tandem repeats within a late viral gene define the central variable region of African swine fever virus.

The central variable region (CVR) of the African swine fever virus (ASFV) genome is contained within the 9-RL open reading frame (ORF). ORF 9-RL of the ASFV isolate Malawi Lil-20/1 predicts a protein of 614 amino acids with amino- and carboxy-terminal hydrophobic regions and a centrally located hydrophilic region. The CVR of the genome, located centrally within this ORF, is 372 bp and contains a 132-bp direct repeat. The translated CVR within ORF 9-RL contains 31 tandem tetramers, predominantly NADT, NANT, NVDT, and, in a few cases, CAST, GAST, or CADT. In vitro translation of 9-RL yielded a 94-kDa protein that was strongly reactive with convalescent pig serum while monospecific 9-RL antiserum identified a late viral protein of 94 kDa in ASFV-infected macrophages. The protein, detected by immunofluorescence staining with 9-RL antiserum, was distributed homogeneously throughout the cytoplasm of infected Vero cells. 9-RL protein size varied among different viral isolates and among cell-culture-adapted viruses. Protein size increased proportionately with the degree of cell culture adaptation and was directly correlated with the size of the CVR present within the ORF (300-500 bp). Analysis of the number and composition of tandem tetramers present within the CVR of a given ASFV isolate may prove useful for identifying and/or grouping ASFV isolates.

African Swine Fever Virus↗
PubMed1996

Cholera-Brucella Cross-Reaction: A New Potential Diagnostic Problem for Travelers to Latin America.

Background: Brucellosis is an endemic disease in Latin America and other countries. Serologic cross-reaction between cholera and Brucella infection is well recognized. Since the introduction to cholera in 1991 in Latin America, interpreting serologic tests has become potentially problematic. This study attempts to evaluate this problem. Methods: Tube agglutination tests were performed to detect Brucella antibodies in 44 Peruvian adult patients with moderate to severe diarrhea due to Vibrio cholerae O1 El Tor infection. These patients had no prior history and no clinical evidence of brucellosis. Results: False positive reactions were observed in 43.2% and 15.9% of the patients when cut-off points of >= 1/80 and >= 1/160 titer, respectively, were selected. These false positive reactions occurred within 4 to 14 days after the onset of diarrhea. The cross-reactivity decreased at the end of the fifth week (only 8.33% had a positive value at the fifth week). Conclusions: Physicians should be alert to the false positive reaction to Brucella in patients with diarrhea. This is relevant to the evaluation of febrile illness in patients coming from developing countries where they could have been exposed to cholera.

Journal Article↗
PubMed1996

A new microplate red blood cell monolayer technique for screening and identifying red blood cell antibodies.

A new method has been developed to immobilize red blood cells in wells of microplates using a cell fixation buffer. This method has been employed for detecting and identifying red blood cell antibodies with greater sensitivity than haemagglutination antiglobulin tests, without loss of specificity. This method decreases the amount of test erythrocytes and anti-human globulin reagents employed per test, consequently lowering the cost.

Antibodies↗
PubMed1996

Gender differences in sexual practices and sexually transmitted infections among adults in Lima, Peru.

OBJECTIVES: This study examined the prevalences of antibodies to Treponema pallidum, Chlamydia trachomatis, and herpes simplex virus type 2 in a sample of Peruvian adults. METHODS: Among adults seeking health certification in Lima, Peru, 600 were randomly selected to undergo interviews and serologic testing. RESULTS: Men's reported mean lifetime number of partners (10.6) far exceeded women's (1.1), yet antibody to sexually transmitted infection pathogens among sexually experienced participants was 2.8 times more prevalent among women than among men. Among men, female sex workers accounted for 37% of recent partners, and only sex with female sex workers while using condoms less than half of the time was independently associated with antibody (odds ratio = 3.6, 95% confidence interval = 1.5, 8.8). among women, number of partners was associated with any sexually transmitted infection antibody, while intercourse before 18 years of age was associated with C trachomatis antibody. At every level of perceived risk, sexually transmitted infection antibody was more frequent among women. CONCLUSIONS: Men having unprotected sex with female sex workers had the greatest risk of acquiring infections and (by inference) of transmitting them to women.

Adult↗
PubMed1995

A 10-amino-acid linear sequence of VP1 of foot and mouth disease virus containing B- and T-cell epitopes induces protection in mice.

The area of foot and mouth disease virus (FMDV) comprising residues 140 and 160 of capsid protein VP1 has been used extensively as an immunogen in natural and experimental hosts. A detailed epitope mapping of this region, however, has not been reported. For this purpose a synthetic peptide containing the residues 135 to 160 (p135-160) of VP1 of FMDV O1 Campos was analyzed for its T- and B-cell epitopes. The p135-160 is highly immunogenic, either by itself or coupled to a carrier protein (BSA), elicits a long-lasting neutralizing antibody response in mice, and provides solid protection against virulent challenge. By using a set of synthetic 10mer overlapping peptides, which cover the entire sequence 135-160 of VP1, we have shown that at least four discrete B epitopes are regularly distributed along the peptide. Although immunization with each of the 10mers coupled with BSA as a carrier protein induced peptide-specific antibody responses, individually none of the 10mers was able to induce neutralizing antibodies. However, anti-135-160 antibodies sorted by immunoaffinity chromatography using each of the 10mers revealed the existence of at least four discrete neutralizing sites: one spanning residues 135-144, at least two more between residues 140 and 154, and another in the region 150-160. Moreover, T-cell epitopes were identified, both by antigen-dependent proliferation assays and by adoptive cell transfer. By both methods, a T-cell epitope was located in the area comprising residues 135-144; the cell transfer experiment, which seems to be more sensitive, also identified a second T-cell epitope between residues 150 and 160. Interestingly, when the region 135-144, which contains both B- and T-cell epitopes, was in a tandem repeat configuration it induced a strong neutralizing antibody response in mice and solid protection against the challenge.

Amino Acid Sequence↗
PubMed1995

Efficacy and tolerability of ciprofloxacin prophylaxis in adult household contacts of patients with cholera.

We conducted a randomized double-blinded study in Lima, Peru, to assess the tolerability and efficacy of a single 250-mg dose of ciprofloxacin in preventing diarrhea and Vibrio cholerae O1 infection among household contacts of bacteriologically confirmed index cases. Adult household contacts with negative baseline stool cultures were included. A total of 213 household contacts were evaluable. The study drugs were well tolerated in both groups. Ciprofloxacin did not prevent the acquisition of V. cholerae O1 infection nor the development of diarrhea. However, in a subgroup of 30 household contacts with positive baseline stool cultures a reduction in the bacterial load and a trend toward prevention of diarrhea were observed among ciprofloxacin recipients. When all household contacts were evaluated, a trend toward prevention of diarrhea was observed with the prophylactic regimen. Ciprofloxacin failed to prevent V. cholerae O1 infections during a period of low transmissibility.

Administration, Oral↗
PubMed1995

Ciprofloxacin for the treatment of cholera: a randomized, double-blind, controlled clinical trial of a single daily dose in Peruvian adults.

We conducted a randomized, double-blind clinical trial to compare ciprofloxacin (250 mg once a day for 3 days) with tetracycline (500 mg four times a day for 3 days) in terms of efficacy and safety in the treatment of moderate-to-severe cholera in Peruvian adults. The baseline characteristics of the groups were similar. A total of 202 patients (102 in the tetracycline group and 100 in the ciprofloxacin group) were included in the efficacy analysis. The clinical and bacteriologic efficacies of the two regimens were similar. The study drugs were well tolerated. We conclude that ciprofloxacin given once a day is as effective as the standard tetracycline regimen for the treatment of cholera in adults. The ciprofloxacin regimen may represent an alternative to the standard treatment in areas where Vibrio cholerae O1 strains that are resistant to commonly used antimicrobials are prevalent.

Administration, Oral↗
PubMed1994

An African swine fever virus gene with similarity to the T-lymphocyte surface antigen CD2 mediates hemadsorption.

An open reading frame, LMW8-DR, in the African swine fever virus (ASFV) genome possesses striking similarity to the lymphocyte membrane antigen CD2. All characterized CD2 domains, including the amino-terminal signal sequence, IgV, hinge, IgC2, stalk, transmembrane, and proline-rich carboxy cytoplasmic domains, are highly conserved in the ASFV gene. Critical residues for the binding of the lymphocyte function-associated antigen (LFA-3) and CD59 and for T-cell activation are also partially conserved. LMW8-DR is actively transcribed in ASFV-infected swine macrophages and Vero cells at late times in the infection cycle and Vero and COS cells transiently expressing the LMW8-DR open reading frame hemadsorbed swine red blood cells. The structural and functional similarities of LMW8-DR to CD2, a protein that is involved in cell-cell adhesion and immune response modulation, suggest a possible role in the pathogenesis of ASFV infection.

African Swine Fever Virus↗
PubMed1994

Recognition of B and T cell epitopes by cattle immunized with a synthetic peptide containing the major immunogenic site of VP1 FMDV 01 Campos.

The precise location of B and T cell epitopes have been established in a peptide containing the major immunogenic site (residues 135-160) of FMDV strain 01 Campos (01C) VP1. The peptide (p135-160), administered free or conjugated to bovine serum albumin, induced complete protection in guinea pigs and a strong neutralizing antibody (NAb) response in cattle. Using a set of partially overlapping peptides it was shown that although several B cell epitopes were distributed along the p135-160, the residues responsible for the induction of NAb were restricted to the amino acids 135-144. In addition, bovines immunized with the p135-160 showed a strong proliferative response to this peptide but a very poor response against purified virus. Two T-epitopes were located in the 135-160 sequence: one on the region 135-144 and the other in the region 150-160. The immunodominance of these two T cell epitopes was confirmed in cattle immunized with inactivated virus vaccines.

Amino Acid Sequence↗