karina juliana acosta garcia - Academia.edu (original) (raw)

Papers by karina juliana acosta garcia

Research paper thumbnail of How Regulatory CD25+CD4+ T Cells Impinge on Tumor Immunobiology: The Differential Response of Tumors to Therapies

The Journal of Immunology, 2007

Aiming to get a better insight on the impact of regulatory CD25 ؉ CD4 ؉ T cells in tumor-immunobi... more Aiming to get a better insight on the impact of regulatory CD25 ؉ CD4 ؉ T cells in tumor-immunobiology, a simple mathematical model was previously formulated and studied. This model predicts the existence of two alternative modes of uncontrolled tumor growth, which differ on their coupling with the immune system, providing a plausible explanation to the observation that the development of some tumors expand regulatory T cells whereas others do not. We report now the study of how these two tumor classes respond to different therapies, namely vaccination, immune suppression, surgery, and their different combinations. We show 1) how the timing and the dose applied in each particular treatment determine whether the tumor will be rejected, with or without concomitant autoimmunity, or whether it will continue progressing with slower or faster pace; 2) that both regulatory T cell-dependent and independent tumors are equally sensitive to vaccination, although the former are more sensitive to T cell depletion treatments and are unresponsive to partial surgery alone; 3) that surgery, suppression, and vaccination treatments, can synergistically improve their individual effects, when properly combined. Particularly, we predict rational combinations helping to overcome the limitation of these individual treatments on the late stage of tumor development.

Research paper thumbnail of Erratum to: Small microcapsules of crystal proteins and spores of Bacillus thuringiensis by an emulsification/internal gelation method

Bioprocess and Biosystems Engineering, 2011

Research paper thumbnail of Analysis of unconventional approaches for the rapid detection of surface lectin binding ligands on human cell lines

Acta Histochemica, 2006

This laboratory has developed and used a novel histochemical assay using derivatized agarose bead... more This laboratory has developed and used a novel histochemical assay using derivatized agarose beads for over a decade to examine the surface properties of various cell types. Most recently we have used this assay to examine lectin binding ligands on two human cell types, CCL-220, a colon cancer cell line, and CRL-1459, a non-cancer colon cell line. We found that CCL-220 cells bound specific lectins better than CRL-1459, and this information was used to test for possible differential toxicity of these lectins in culture, as a possible approach in the design of more specific anti-cancer drugs. Although we have examined the validity of the bead-binding assay in sea urchin cell systems, we have not validated this technique for mammalian cells. Here the binding results of the bead assay are compared with conventional fluorescence assays, using lectins from 3 species (Triticum vulgaris, Phaseolus vulgaris, and Lens culinaris) on the 2 colon cell lines. These lectins were chosen because they seemed to interact with the two cell lines differently. Binding results obtained using both assays were compared for frozen, thawed and fixed; cultured and fixed; and live cells. Both qualitative and quantitative fluorescence results generally correlated with those using the bead assay. Similar results were also obtained with all of the 3 different cell preparation protocols. The fluorescence assay was able to detect lower lectin binding ligand levels than the bead assay, while the bead assay, because it can so rapidly detect cells with large numbers of lectin binding ligands, is ideal for initial screening studies that seek to identify cells that are rich in surface binders for specific molecules. The direct use of frozen, thawed, and fixed cells allows rapid mass screening for surface molecules, without the requirement for costly and time consuming cell culture.

Research paper thumbnail of How Regulatory CD25+CD4+ T Cells Impinge on Tumor Immunobiology: The Differential Response of Tumors to Therapies

The Journal of Immunology, 2007

Aiming to get a better insight on the impact of regulatory CD25 ؉ CD4 ؉ T cells in tumor-immunobi... more Aiming to get a better insight on the impact of regulatory CD25 ؉ CD4 ؉ T cells in tumor-immunobiology, a simple mathematical model was previously formulated and studied. This model predicts the existence of two alternative modes of uncontrolled tumor growth, which differ on their coupling with the immune system, providing a plausible explanation to the observation that the development of some tumors expand regulatory T cells whereas others do not. We report now the study of how these two tumor classes respond to different therapies, namely vaccination, immune suppression, surgery, and their different combinations. We show 1) how the timing and the dose applied in each particular treatment determine whether the tumor will be rejected, with or without concomitant autoimmunity, or whether it will continue progressing with slower or faster pace; 2) that both regulatory T cell-dependent and independent tumors are equally sensitive to vaccination, although the former are more sensitive to T cell depletion treatments and are unresponsive to partial surgery alone; 3) that surgery, suppression, and vaccination treatments, can synergistically improve their individual effects, when properly combined. Particularly, we predict rational combinations helping to overcome the limitation of these individual treatments on the late stage of tumor development.

Research paper thumbnail of Erratum to: Small microcapsules of crystal proteins and spores of Bacillus thuringiensis by an emulsification/internal gelation method

Bioprocess and Biosystems Engineering, 2011

Research paper thumbnail of Analysis of unconventional approaches for the rapid detection of surface lectin binding ligands on human cell lines

Acta Histochemica, 2006

This laboratory has developed and used a novel histochemical assay using derivatized agarose bead... more This laboratory has developed and used a novel histochemical assay using derivatized agarose beads for over a decade to examine the surface properties of various cell types. Most recently we have used this assay to examine lectin binding ligands on two human cell types, CCL-220, a colon cancer cell line, and CRL-1459, a non-cancer colon cell line. We found that CCL-220 cells bound specific lectins better than CRL-1459, and this information was used to test for possible differential toxicity of these lectins in culture, as a possible approach in the design of more specific anti-cancer drugs. Although we have examined the validity of the bead-binding assay in sea urchin cell systems, we have not validated this technique for mammalian cells. Here the binding results of the bead assay are compared with conventional fluorescence assays, using lectins from 3 species (Triticum vulgaris, Phaseolus vulgaris, and Lens culinaris) on the 2 colon cell lines. These lectins were chosen because they seemed to interact with the two cell lines differently. Binding results obtained using both assays were compared for frozen, thawed and fixed; cultured and fixed; and live cells. Both qualitative and quantitative fluorescence results generally correlated with those using the bead assay. Similar results were also obtained with all of the 3 different cell preparation protocols. The fluorescence assay was able to detect lower lectin binding ligand levels than the bead assay, while the bead assay, because it can so rapidly detect cells with large numbers of lectin binding ligands, is ideal for initial screening studies that seek to identify cells that are rich in surface binders for specific molecules. The direct use of frozen, thawed, and fixed cells allows rapid mass screening for surface molecules, without the requirement for costly and time consuming cell culture.