Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Alfonso López is active.

Publication


Featured researches published by Alfonso López.


European Journal of Immunology | 2016

Exploring the immunosuppressive potential of venom-derived molecules

R. Ryan; Maria P. Ikonomopoulou; O. Haigh; Lutzky; Jimenez R. Martinez; C. Ratnatunga; Y. Wong; Rojas, Leal, I; Alfonso López; Bryan G. Fry; Herzig; Glenn F. King; John J. Miles

CD4+Foxp3+ regulatory T cells (Tregs) are the main regulators of peripheral tolerance and prevent the development of fatal autoimmune disease in humans and mice. Furthermore, Tregs have also been implicated in suppressing anti-tumour immune responses and are often enriched at sites of primary and metastatic tumours. While studies have shown the effect of Treg ablation on the control of primary tumours, few studies have examined their contribution to metastasis progression. In this thesis I hypothesised that the depletion of Tregs could promote control over metastasis. To address this, a highly metastatic murine mammary carcinoma cell line 4T1 was injected into transgenic mice expressing the diphtheria toxin receptor in Foxp3+ cells. Foxp3+ cells were depleted by administration of diphtheria toxin and the impact of this on growth of primary tumours and metastases was assessed and measured in vitro clonogenic assays. Results of these experiments indicated that Tregdepletion led to control of primary tumour growth and in some mice to control of metastases. Control of metastases was linked to control of primary tumour growth. In order to measure metastasis in vivo, a PET/CT imaging technique was optimized. Primary tumours and large metastatic nodules were successfully imaged in mice using F18 FDG as a radiotracer. However, the studies described herein revealed that micrometastases in mouse lungs were too small to be reliably identified using PET data parameters. CT imaging did however enable detection of increases in tissue density within the lungs, which was suggestive of micrometastases. Data obtained in this way also indicated that Treg-depletion promotes control of metastasis in some mice. Collectively, the findings described in this thesis indicate that Tregdepletion can contribute to control of metastatic disease and should therefore represent an important component of novel immunotherapies.Changes in microbiome, mucosal immunity and intestinal integrity have been associated with the onset of Type 1 Diabetes (T1D) in children. Toll-like Receptors (TLR) have been associated all three factors. The role of TLR and their effects on microbiome in autoimmunity were studied by crossing TLR1,2,4,6,9 and MyD88 targeted deficiency mutations to the type 1 diabetes (T1D)-prone NOD mouse strain. While NOD.Tlr9-/- and NOD.Tlr6-/- mice were unaffected, T1D in NOD.Tlr4-/- and NOD.Tlr1-/- mice was exacerbated and that in NOD.Myd88-/- and NOD.Tlr2-/- mice ameliorated. Physical parameters of the intestines were compared; ileal weight was reduced in NOD.Tlr1-/-mice. Similarly, by histology, these mice had reduced villus length and width. The intestinal microbiomes of NOD wild-type (WT), NOD.Tlr1-/-, NOD.Tlr2-/- and NOD.Tlr4-/- mice were compared by high throughput sequencing of 16S ribosomal DNA (rDNA), in two cohorts, 18 months apart. Analysis of caecal 16S sequences clearly resolved the mouse lines and there were significant differences in beta diversity between the strains, with individual bacterial species contributing greatly to the differences in the microbiota of individual TLR-deficient strains. To test the relationship between microbiome and T1D, all strains were re-derived onto the parental NOD/Lt line and the incidence of T1D re-assessed within two generations. All rederived lines expressed an incidence of disease similar to that of the parental line. TLR deficiencies are associated with changes in microbiome; changes of microbiome are associated with T1D; the effects of TLR deficiencies on T1D appear to be mediated by their effects on gut flora.Intestinal TCRb+CD4-CD8b-CD8a+ (CD8aa) IELs alleviate T cell induced colitis and have been suggested to play a role in virus infection and cancer. Their thymic development has been elucidated to some extent, as IEL precursors (IELp) are known to be CD4-CD8-CD5+TCRb+, but is not yet fully understood. Within the thymus, mature IELp were identified based on their expression of CD122 and MHC class I. Two major phenotypic subsets exist within this mature thymic IELp population: a PD1+Tbet- population that preferentially expresses a4b7, and a PD1-Tbet+ population with preferential CD103 expression. These two populations were also distinct in their Valpha repertoire. The PD1+a4b7+ population contains clones that are strongly self-reactive as judged by Nur77GFP and their dramatic increase in Bim deficient mice, while the PD1-Tbet+ population did not show these characteristics. Both gave rise to CD8aa IELs upon adoptive transfer into RAG-/- recipients. However intrathymic labeling revealed that PD1+a4b7+ IELp were the major thymic emigrating population, and emigration was S1P1-dependent. In contrast, PD1-Tbet+ IELp expressed CXCR3, were retained, and accumulated in the thymus with age. Preliminary immunofluorescence data furthermore indicate differential thymic cortico-medullary localization of the IELp subtypes. These experiments more precisely define the behavior of IEL precursors.


European Journal of Immunology | 2016

Investigating venom-derived molecules that augment human immune function

R. Jimenez-Martinez; Maria P. Ikonomopoulou; O. Haigh; Lutzky; I Leal-Rojas; R. Ryan; C. Ratnatunga; Y. Wong; Alfonso López; Bryan G. Fry; Herzig; Glenn F. King; John J. Miles

CD4+Foxp3+ regulatory T cells (Tregs) are the main regulators of peripheral tolerance and prevent the development of fatal autoimmune disease in humans and mice. Furthermore, Tregs have also been implicated in suppressing anti-tumour immune responses and are often enriched at sites of primary and metastatic tumours. While studies have shown the effect of Treg ablation on the control of primary tumours, few studies have examined their contribution to metastasis progression. In this thesis I hypothesised that the depletion of Tregs could promote control over metastasis. To address this, a highly metastatic murine mammary carcinoma cell line 4T1 was injected into transgenic mice expressing the diphtheria toxin receptor in Foxp3+ cells. Foxp3+ cells were depleted by administration of diphtheria toxin and the impact of this on growth of primary tumours and metastases was assessed and measured in vitro clonogenic assays. Results of these experiments indicated that Tregdepletion led to control of primary tumour growth and in some mice to control of metastases. Control of metastases was linked to control of primary tumour growth. In order to measure metastasis in vivo, a PET/CT imaging technique was optimized. Primary tumours and large metastatic nodules were successfully imaged in mice using F18 FDG as a radiotracer. However, the studies described herein revealed that micrometastases in mouse lungs were too small to be reliably identified using PET data parameters. CT imaging did however enable detection of increases in tissue density within the lungs, which was suggestive of micrometastases. Data obtained in this way also indicated that Treg-depletion promotes control of metastasis in some mice. Collectively, the findings described in this thesis indicate that Tregdepletion can contribute to control of metastatic disease and should therefore represent an important component of novel immunotherapies.Changes in microbiome, mucosal immunity and intestinal integrity have been associated with the onset of Type 1 Diabetes (T1D) in children. Toll-like Receptors (TLR) have been associated all three factors. The role of TLR and their effects on microbiome in autoimmunity were studied by crossing TLR1,2,4,6,9 and MyD88 targeted deficiency mutations to the type 1 diabetes (T1D)-prone NOD mouse strain. While NOD.Tlr9-/- and NOD.Tlr6-/- mice were unaffected, T1D in NOD.Tlr4-/- and NOD.Tlr1-/- mice was exacerbated and that in NOD.Myd88-/- and NOD.Tlr2-/- mice ameliorated. Physical parameters of the intestines were compared; ileal weight was reduced in NOD.Tlr1-/-mice. Similarly, by histology, these mice had reduced villus length and width. The intestinal microbiomes of NOD wild-type (WT), NOD.Tlr1-/-, NOD.Tlr2-/- and NOD.Tlr4-/- mice were compared by high throughput sequencing of 16S ribosomal DNA (rDNA), in two cohorts, 18 months apart. Analysis of caecal 16S sequences clearly resolved the mouse lines and there were significant differences in beta diversity between the strains, with individual bacterial species contributing greatly to the differences in the microbiota of individual TLR-deficient strains. To test the relationship between microbiome and T1D, all strains were re-derived onto the parental NOD/Lt line and the incidence of T1D re-assessed within two generations. All rederived lines expressed an incidence of disease similar to that of the parental line. TLR deficiencies are associated with changes in microbiome; changes of microbiome are associated with T1D; the effects of TLR deficiencies on T1D appear to be mediated by their effects on gut flora.Intestinal TCRb+CD4-CD8b-CD8a+ (CD8aa) IELs alleviate T cell induced colitis and have been suggested to play a role in virus infection and cancer. Their thymic development has been elucidated to some extent, as IEL precursors (IELp) are known to be CD4-CD8-CD5+TCRb+, but is not yet fully understood. Within the thymus, mature IELp were identified based on their expression of CD122 and MHC class I. Two major phenotypic subsets exist within this mature thymic IELp population: a PD1+Tbet- population that preferentially expresses a4b7, and a PD1-Tbet+ population with preferential CD103 expression. These two populations were also distinct in their Valpha repertoire. The PD1+a4b7+ population contains clones that are strongly self-reactive as judged by Nur77GFP and their dramatic increase in Bim deficient mice, while the PD1-Tbet+ population did not show these characteristics. Both gave rise to CD8aa IELs upon adoptive transfer into RAG-/- recipients. However intrathymic labeling revealed that PD1+a4b7+ IELp were the major thymic emigrating population, and emigration was S1P1-dependent. In contrast, PD1-Tbet+ IELp expressed CXCR3, were retained, and accumulated in the thymus with age. Preliminary immunofluorescence data furthermore indicate differential thymic cortico-medullary localization of the IELp subtypes. These experiments more precisely define the behavior of IEL precursors.


Mesoamerican Agronomy | 2000

New maize cultivars with agronomic potential for the humid-tropics.

Mariano Mendoza; Arnoldo Oyervides; Alfonso López


Agronomía Mesoamericana | 2014

Separación de los efectos epistáticos, aditivos y dominantes en maíz

Mariano Mendoza; Alfonso López; Sergio Rodríguez; Carlos De León; Dan Jeffers


Revista Mexicana de Fitopatología | 2003

Herencia Genética y Citoplásmica de la Resistencia a la Pudrición de la Mazorca del Maíz (Zea mays L.) Causada por Fusarium moniliforme Sheld

Mariano Mendoza; Alfonso López; Arnoldo Oyervides; Gaspar Martínez; Carlos De León; Ernesto Moreno


Agronomía Mesoamericana | 2000

Análisis de crecimiento en siete variedades de papa (solanum tuberosum l.)

Fernando Borrego; José M. Fernández; Alfonso López; Víctor M. Parga; Margarita Murillo; Adrián Carvajal


Agronomía Mesoamericana | 2001

Evaluación agronómica de melón (Cucumis melo L.) bajo condiciones de campo

Fernando Borrego; Alfonso López; José M. Fernández; Margarita Murillo; Sergio Rodríguez; Alfonso Reyes


Agronomía Mesoamericana | 2001

Evaluación agronómica de tomate(licopersicon esculentum m) en invernadero

Fernando Borrego; Alfonso López; José M. Fernández; Margarita Murillo; Sergio Rodríguez; Alfonso Reyes


Agronomía Mesoamericana | 2000

Nuevos cultivares de maíz con potencial agronómico para el trópico húmedo

Mariano Mendoza; Arnoldo Oyervides; Alfonso López


Agronomía Mesoamericana | 2000

Análisis de crecimiento en siete variedades de papa

Fernando Borrego; José M. Fernández; Alfonso López; Víctor M. Parga; Margarita Murillo; Adrián Carvajal

Collaboration


Dive into the Alfonso López's collaboration.

Top Co-Authors

Avatar

Sergio Rodríguez

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Fernando Borrego

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

José M. Fernández

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Margarita Murillo

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Mariano Mendoza

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Alfonso Reyes

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Francisco J. Almanza

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Carlos De León

International Maize and Wheat Improvement Center

View shared research outputs
Top Co-Authors

Avatar

Adrián Carvajal

Universidad Autónoma Agraria Antonio Narro

View shared research outputs
Top Co-Authors

Avatar

Bryan G. Fry

University of Queensland

View shared research outputs
Researchain Logo
Decentralizing Knowledge