Diagnostic and prophylactic potential of a stabilized foot-and-mouth disease serotype Asia1 virus like particles designed through a structure guided approach.

Intact capsids of foot-and-mouth disease virus (FMDV) play a vital role in eliciting a protective immune response. Any change in the physico-chemical environment of the capsids results in dissociation and poor immunogenicity. Structural bioinfomatics studies have been carried out to predict the amino acids at the interpentameric region that resulted in the identification of mutant virus-like particles(VLPs) of FMDV serotype Asia1/IND/63/1972. The insect cell expressed VLPs were evaluated for their stability by sandwich ELISA. Among 10 mutants, S93H showed maximum retention of antigenicity at different temperatures, indicating its higher thermal stability as revealed by the in-silico analysis and retained the antigenic sites of the virus demonstrated by Sandwich ELISA. The concordant results of the liquid phase blocking ELISA for estimation of antibody titre of known sera with stable mutant VLP as antigen in place of virus antigen demonstrate its diagnostic potential. The stable mutant VLP elicited a robust immune response with 85.6 % protection in guinea pigs against virus challenge. The stabilized VLP based antigen requires minimum biosafety and cold storage for production and transit besides, complying with differentiation of infected from vaccinated animals. It can effectively replace the conventional virus handling during antigen production for prophylactic and diagnostic use.

Progressive growth of a murine T cell lymphoma alters population kinetics and cell viability of macrophages in a tumor-bearing host.

Tumor progression induces infiltration of immune cell populations at the site of tumor growth. Infiltrated leukocyte population including monocyte and macrophages interacts with tumor cells and tumor microenvironment and results in the suppression of macrophage functions. Impaired functions of macrophages result in the suppression/inhibition of cell-mediated immunity leading to inefficient antitumor immune responses. Impaired macrophage population invariably helps in immune selection of tumor leading to uninterrupted growth and progression in the host. Murine T cell lymphoma designated as Dalton's lymphoma is highly immunosuppressive and invasive tumor of T cell origin, which completely paralyzes the host's immune system resulting in a very short life span of the host. Progressive growth of Dalton's lymphoma (DL) cells has been known to inhibit the release of inflammatory cytokines and effector mediator molecules. In this study, we demonstrate that intraperitoneal transplant of DL cells in normal healthy host induces a rapid increase in macrophage cell population during early stage of tumor progression and progressive decrease in tumor-associated macrophage population and reduced survival of macrophages in advance stage of tumor burden.

IL-13 from Th2-type cells suppresses induction of antigen-specific Th1 immunity in a T-cell lymphoma.

Dalton's lymphoma (DL) is a transplantable T-cell lymphoma of spontaneous origin, characterized by highly invasive and immunosuppressive property. Progression of DL cells results into an imbalance of T helper type 1 (T(h)1)/T helper type 2 (T(h)2)-type cytokine in the host, which is partly responsible for DL-induced severe immunosuppression and DL cell progression. In this study, we have shown the role of IL-13 in the regulation of T(h)1 immunity in both normal healthy and DL-bearing host. IL-13 pre-treatment inhibits the induction of 2,4-dinitro-1-fluorobenzene-induced contact hypersensitivity and delayed-type hypersensitivity (DTH) in antigen-challenged mice, which have been confirmed by neutralizing IL-13 by systemic delivery of non-signaling decoy receptor IL-13Ralpha2. Furthermore, IL-13 neutralization enhances the splenocyte proliferation, which has been inhibited by IL-13 administration. Adoptive transfer of splenocyte from IL-13-pre-treated mice and macrophages incubated with IL-13 and pulsed with antigens suppresses the DTH as well in antigen-challenged recipient mice. In addition, it also suppresses the production of pro-inflammatory cytokine and C-C chemokine in DTH footpad. Furthermore, IL-13 neutralization not only enhances the DTH reaction but also increases longevity and survival of DL-bearing host, which suggests that blocking/inactivating systemic IL-13 enhances T(h)1 immunity, and therefore, effects to diminish IL-13 production may have therapeutic value in a host bearing T-cell lymphoma.

Overexpression of interleukin-13 in a murine T-cell lymphoma: a possible factor of DL-induced immunosuppression and tumor progression.

Interleukin-13 (IL-13) is a T(H)2 cytokine that plays a crucial role in the pathophysiology of tumors and favor tumor growth and recurrence by negative regulation of tumor immunosurveillance. In the present investigation, we have determined the IL-13 level in the serum and ascitic fluid of the DL-bearing host and the possible source of IL-13 in the ascitic fluid. IL-13 level was elevated in serum and ascitic fluid of host bearing a transplantable T-cell lymphoma. DL cells as well as tumor-associated macrophages express and secrete IL-13 in the milieu, which provide further insight for DL-induced immunosuppression in a tumor-bearing host.

Autologous Hsp70 induces antigen specific Th1 immune responses in a murine T-cell lymphoma.

Heat Shock protein-70 derived from tumor cells is highly immunogenic and induces specific anti-tumor immune response by directly activating cytotoxic CD8(+) T cells. Additionally, Hsp70 is known to be a strong activator of antigen presenting cells and therefore, up regulates the production of pro-inflammatory cytokines and chemokines. In this study, we have shown the effect of tumor-derived Hsp70 on the induction of delayed type hypersensitivity reaction in a T cell lymphoma bearing mice. The autologous Hsp70 augments contact hypersensitivity and delayed type hypersensitivity responses in mice challenged with allergen in vehicle and antigens respectively. The adoptive transfer of splenocytes derived from Hsp70 immunized mice is able to enhance delayed type hypersensitivity response in antigen challenged normal and DL-bearing host. Furthermore, adoptive transfer of macrophages incubated with autologous Hsp70 also enhances DTH reactivity in mice. The pro-inflammatory cytokines and C-C chemokines are found to be elevated in the DTH footpad extract of antigen challenged normal and DL-bearing mice. Increased production of IFN-gamma and MIP-1alpha+/- suggest that autologous Hsp70 augments the recruitment of antigen specific Th1 cells, which further secretes pro-inflammatory cytokines and C-C chemokines mediating the hypersensitivity reaction upon challenge with antigens.

Interleukin-13 neutralization modulates interleukin-13 induced suppression of reactive oxygen species production in peritoneal macrophages in a murine T-cell lymphoma.

IL-13 is a Th2 cytokine that regulates the effector functions and alters the phenotype and function of normal macrophages switching to alternatively activated or type II polarized macrophages. The type II polarized macrophages differ from normal macrophages greatly in terms of receptor expression, NO and other cytokine production. It produces chemokines that preferentially attract Th2 cells, which increases the local concentration of Th2 cytokines including IL-13. As a result, normal macrophage population gets polarized as type II macrophages at the site of the tumor-microenvironment. In the present investigation, we have determined the IL-13 serum level in DL-bearing host and the effect of IL-13 on peritoneal macrophages harvested from normal healthy, control DL-bearing, and treated DL-bearing mice with respect to reactive oxygen intermediate production. It has been observed that IL-13 significantly inhibits the ROI generation in all macrophage types while by neutralizing with invivo administration of IL-13R*2 and/or potentiation with Th1 cytokine, the production of reactive oxygen intermediate increases, which indicates that IL-13R*2 and/or potentiation with Th1 cytokine could restore the cytotoxic ability of macrophage in a murine T-cell lymphoma.

A benzophenanthridine alkaloid, chelerythrine induces apoptosis in vitro in a Dalton's lymphoma.

PURPOSE: The aim of this study was to investigate the effect of chelerythrine on DL cell apoptosis in an in vitro experimental setup. MATERIALS AND METHODS: For tumor model, spontaneous occurring T-cell lymphoma designated as Dalton's lymphoma (DL) was selected. Double staining, transmission electron microscope (TEM), fluorescence microscopy, Western blotting, Reverse Transcriptase-Polymerase Chain Reaction, and DNA fragmentation assay were used to detect heat shock factor 1 (HSF1) and hsp70 expression and PKC phosphorylation, and apoptotic characteristic of DL cells. RESULTS: Chelerythrine exposure resulted in significant morphological alteration comparable to that of apoptosis. Furthermore, it was confirmed by fluorescence microscopy, TEM analysis, and DNA fragmentation assay that 10 µg/mL of chelerythrine is capable of inducing apoptosis in DL cells. The suppression in HSF1 expression and subsequent inhibition of hsp70 expression in chelerythrine-treated DL cells suggest that chelerythrine induces apoptosis in DL cells by inhibiting the expression of these cytoprotective proteins. CONCLUSION: Chelerythrine is capable of inducing apoptosis DL cells in vitro and therefore, it could be useful in combating tumor growth and progression.

Anti-tumor immunity and mechanism of immunosuppression mediated by tumor cells: role of tumor-derived soluble factors and cytokines.

The immune system plays a crucial role in the protection against tumor growth and progression. However, the activation of the immune system against the neoplastic cells does not always occur and, therefore, tumor cells are able to grow and progress continually in the host. It has now been realized that tumor cells themselves produce many of the important factors that are responsible for dismounting of effective immune response. These tumor-derived soluble factors invariably subdue the functions of almost every immune cell population. Therefore, we attempted to underline the mechanism of anti-tumor immune response and immunosuppression induced by tumor cells.

Gender dichotomy in antibody response in a T-cell lymphoma: involvement of IL-13 and gonadal hormones.

PROBLEM: Dalton's lymphoma (DL) shows very high interleukin (IL)-13 level in the serum and ascitic fluid. Therefore, in the present study, we investigated if any sexual dichotomy in the level of IL-13, and resulting B-cell activation and Ig subclass switching also exist in the tumor-bearing host. METHOD OF STUDY: Serum and ascitic fluid of different groups of DL-bearing mice were isolated and IL-13 level and various Ig levels in serum were quantified by double-sandwich enzyme-linked immunosorbent assay. Further, the B cells were isolated from DL-bearing mice and effects of various concentrations of IL-13 and sex steroids were measured. RESULTS: Uncastrated and hormone replaced DL-bearing mice showed sexual dichotomy in IL-13 level, and subsequent difference in Ig-level and this was found to be more pronounced in females. Similarly, in vitro study suggested that estrogen treatment, in combination with IL-13, strongly modulates B-cell Ig switching in comparison to testosterone treatment in association with IL-13. CONCLUSION: It can be concluded that IL-13, in concert with gonadal hormones, differentially modulates the B-cell function in a tumor-bearing host.