Lack of lymphoid chemokines CCL19 and CCL21 enhances allergic airway inflammation in mice.

Lymphoid chemokines CCL19 and CCL21 are crucial for the recruitment of circulating naive T cells into lymph nodes. However, it is not completely known how they contribute to the development of allergic diseases. To determine whether the lack of CCL19 and CCL21 affects allergic airway inflammation, CCL19- and CCL21-deficient [paucity of lymph node T cells (plt/plt)] and wild-type (WT) mice were immunized intra-peritoneally and then challenged intra-nasally with chicken ovalbumin (OVA). Plt/plt mice developed more severe allergic airway inflammation characterized by increased eosinophils and lymphocytes in bronchoalveolar lavage (BAL) and profound inflammation in peribronchiolar and perivascular regions than did WT mice. CD4+ alpha4 integrin+ and CD4+ beta7 integrin+ T cells were significantly increased in the BAL of OVA-immunized and OVA-challenged (OVA/OVA) plt/plt mice compared with OVA/OVA WT mice. Moreover, there were higher levels of IL-4 and IL-13 mRNAs and lower levels of IL-2 and IFN-gamma mRNAs in inflamed lungs of OVA/OVA plt/plt mice compared with OVA/OVA WT mice. Plt/plt mice produced higher levels of total and OVA-specific IgE antibody. Thus, our results suggest that lack of lymphoid chemokines CCL19 and CCL21 enhances allergic airway inflammation by modulating the recruitment of CD4+ T cells into the lung, the balance between Th1 and Th2 cytokines and the IgE production.

Genetic association of mutation at agouti locus with adrenal x zone morphology in BALB/c mice.

The genetic association of the agouti (a) locus with mouse adrenal X zone morphology on a specific genetic background has been suggested. To confirm this, the adrenal cortices of virgin females were compared histologically between BALB/c (A/A) and its mutant, BALB/c-a/a (a/a). The X zone was similar in the number of constituting cell layers, but different in morphology between the A/A and a/a genotypes. At 70 days of age, it was constituted of vacuolated cells exclusively in A/A and of non-vacuolated and a few vacuolated cells in a/a. At 140 days of age, the X zones contained only vacuolated cells in both genotypes. Therefore, the a (non-agouti) allele might have 2 effects upon the X zone morphology on the BALB/c background; the a allele might suppress vacuolation and delay its onset. However, the zona reticularis seemed to have no association with this locus.

Frequency and resistance of CD95 (Fas/Apo-1) gene-transfected tumor cells to CD95-mediated apoptosis by the elimination and methylation of integrated DNA.

It is important for more effective gene therapies to clarify the mechanisms by which cDNA integrated into cells can maintain or lose its function in vivo. We evaluated genetic and epigenetic events leading to alternation of the introduced CD95 (Fas/Apo-1) gene as a model of gene therapy. Solid tumors formed by CD95 cDNA-transfected hepatoma cells (F6b) were almost completely cured by a single treatment of anti-CD95 monoclonal antibody (mAb) but recurred in gld/gld lpr/lpr mice after initial complete response. Recurred tumors were resistant to repeated mAb treatment. The ratio of resistant cells in tumors was estimated as 4.2 cells per 10(6) cells. The CD95-resistant tumor contained CD95-vanished and CD95-decreased cells. CD95-vanished cells were due to the deletion of CD95cDNA. However, CD95-decreased cells retained CD95cDNA, which was highly methylated when determined with methylation-dependent enzymes and a demethylation reagent, indicating that DNA methylation was responsible for the reduced CD95 expression and resistance to mAb. CD95-decreased cells reduced the CD95 expression further but did not delete cDNA after a second in vivo treatment with anti-CD95 mAb, suggesting that the elimination of cDNA is not induced after its methylation and that cells containing methylated genes became more resistant by further methylation. Thus, the elimination and methylation of integrated cDNA appear to occur through different mechanisms. Our study of resistant tumor cells, which arose by both mutational and epigenetic modifications of the introduced CD95 plasmid, provides important and fundamental information about the fate of introduced cDNA, augmenting the efficiency of gene therapy.

Roles of CXC chemokines and macrophages in the recruitment of inflammatory cells and tumor rejection induced by Fas/Apo-1 (CD95) ligand-expressing tumor.

The role of CD95 ligand (FasL/Apo-1L)-expressing tumors in immunosuppression or immunopotentiation is controversial. CD95L-transfected tumors induce immunopotentiation after vigorous neutrophil infiltration. Thus, the induction of neutrophil infiltration by CD95L seems to play an important role in tumor rejection. The mechanism by which CD95L-expressing tumors cause neutrophil infiltration and antitumor immunity has not been well understood. CXC chemokine receptor 2 (CXCR2) knockout (KO) mice are a powerful tool for studying CXC chemokine-mediated neutrophil infiltration. We investigated the roles of CD95L and chemokines in CD95L-induced antitumor activity by using CXCR2 KO mice and CD95LcDNA-transfected MethA (MethA + CD95L) fibrosarcoma. MethA + CD95L cells were completely rejected in wild-type (WT) and even in KO mice. MethA + CD95L cells injected intraperitoneally (i.p.) induced the recruitment of both neutrophils and macrophages in WT but only macrophages in KO mice, although CXC and CC chemokines were released in both mice. Macrophages incubated with MethA + CD95L cells released CXC and CC chemokines. Macrophages derived from WT and KO but not neutrophils from WT mice induced the recruitment of neutrophils when adoptively i.p. transferred with MethA + CD95L cells into CD95L/CD95-deficient mice. The different recruitment of inflammatory cells between WT and KO mice was attributed to bone marrow (BM) cells by BM transfer experiment. Our results demonstrated that CXC chemokines are essential for neutrophil recruitment and that macrophages but not neutrophils play a critical role in the CD95L-induced infiltration of inflammatory cells and the eradication of CD95L-expressing tumor cells.

Modification of tumor cells with Fas (CD95) antigen gene and Fas ligand (CD95L) gene transfection by electroporation for immunotherapy of cancer.

Electroporation is a method for introducing DNA into cells by using a high-voltage electric field. This method is very simple and easily manipulated. We describe here a method for the modification of tumor cells with the Fas/Apo-1 (CD95) antigen-gene and Fas ligand (FasL)-gene transfection through the use of electroporation, and suggest that the Fas-FasL system is a good target for the induction of apoptosis-mediated antitumor activity. The Fas receptor/ligand system induces apoptosis and plays an important role in regulation of the immune system. In the method described, hepatoma MH134 (Fas- and FasL-) is transfected with murine Fas and FasL cDNA. A single administration of monoclonal anti-Fas antibody efficiently suppresses the growth of F6b (MH134+Neo+Fas) tumors but not that of N1d (MH134+Neo) tumors in gld/gld lpr/lpr mice. MH134+Neo+FasL tumor cells were rejected after the induction of inflammation with infiltration of neutrophils in mice. These results suggest that electroporation and Fas-mediated apoptosis are a good method for inducing of antitumor activity.

A novel method for modification of tumor cells with bacterial superantigen with a heterobifunctional cross-linking agent in immunotherapy of cancer.

Bacterial superantigens (SAGs) bind to cognate Vbeta elements of T-cell receptors on T-cells and to major histocompatibility complex (MHC) class II molecules on antigen-presenting cells to activate T-cell subsets expressing the Vbeta elements. We examined the possibility that the direct binding of SAGs (staphylococcal enterotoxins B [SEB] and A [SEA]) to tumor cells decreases the toxicity of SAGs, and that antitumor immunity can be induced with the aid of T-helper-1 (Th1)-type cytokines and monokines released from T-cells and monocytes, respectively, by activation with SAGs. In this context, we have developed a general method for conjugating SEB and SEA directly to tumor cells with a heterobifunctional cross linking agent, N-(gamma- maleimidobutyryloxy) sulfosuccinimide sodium salt. Using this method, we have succeeded in conjugating SEB to a sufficient extent as to induce strong tumor immunity. Both in vitro T-cell culture with SEB-bearing Meth A cells and in vivo immunization with SEB-bearing Meth A cells induce strong antitumor activity. These results suggest that the direct conjugation of SAGs including SEB and SEA to tumor cells is a powerful and useful method for immunotherapy of cancer.

Inhibitory effects of autoimmune disease by green tea in MRL-Faslprcg/Faslprcg mice.

To investigate whether green tea has inhibitory effects on the development of autoimmune disease (AID), one-month-old MRL-Faslprcg/Faslprcg mice were fed diets containing 2% green tea powder (GTP) for 3 months. At the end of GTP feeding, the weights of body, subcutaneous (s.c.) and intraperitoneal (i.p.) lymph nodes (LN), kidneys, spleen and intraperitoneal adipose tissue (IPAT), serological abnormalities and renal lesions were compared between GTP-fed and control mice. SCLN, IPLN, kidneys and IPAT weights in both sexes, spleen weight in males and body weight increase in males were significantly lower in GTP-fed mice. Particularly, LN hyperplasia and fatty accumulation were markedly reduced by GTP. Serum levels of anti-DNA antibodies and immune complexes (IC) were significantly lowered and proteinuria and blood urea nitrogen tended to be improved by GTP. The incidence of serious glomerulonephritis was significantly lower and nephric vasculitis was almost completely prevented in GTP-fed mice. Moreover, the survival of mice was significantly prolonged by GTP feeding for 6 months. These results indicate that the progression of lupus-like syndrome including glomerulonephritis was significantly delayed by reduced production of autoantibodies and IC in GTP-fed MRL-Faslprcg/Faslprcg mice, which led to the prolonged survival.

Significant role of Fas ligand-binding but defective Fas receptor (CD95) in lymph node hyperplasia composed of abnormal double-negative T cells.

The functional differences between two mutations of the Fas (CD95) locus, Faslpr (lpr) and Faslprcg (lprcg), were investigated using bone marrow (BM) transplantation on the C3H mouse background. Both lpr/lpr and lprcg/lprcg BM transferred caused lymph node (LN) hyperplasia in lpr/+ and lprcg/+ recipients, although it was clearly smaller than that in lpr/lpr and lprcg/lprcg recipients of lpr/lpr and lprcg/lprcg BM. In addition, both BM induced significantly larger LN hyperplasia in lprcg/+ than lpr/+ recipients. Appearance of CD4- CD8-[double negative (DN)] T cells in the periphery is the most consistent phenotype of Fas mutations. Importantly, the proportion of DN T cells was higher in larger LN hyperplasia in the order of lpr/+, lprcg/+ and lpr/lpr or lprcg/lprcg recipients. On the other hand, both lpr/lpr and lprcg/lprcg BM transferred into wild-type (+/+) mice caused marked LN atrophy. The former, but not the latter, induced wasting syndrome. Faslg1d (gld)-homozygous lpr/lpr BM transferred into +/+ mice elicited LN hyperplasia of the same extent as that in lpr/lpr mice transferred with lpr/lpr BM, but not wasting syndrome. Taken together with the fact that DN T cells massively express Fas ligand (FasL), this study implied that FasL overexpressed on DN cells may be involved in the accumulation of DN T cells in LN, LN atrophy and wasting syndrome, and that lprcg Fas, which can bind to Fas ligand but not transduce apoptosis signal into cells, may modulate these pathological conditions by interfering with the binding of FasL to Fas.