(1/331) Vaccination with a recombinant vaccinia virus encoding a "self" antigen induces autoimmune vitiligo and tumor cell destruction in mice: requirement for CD4(+) T lymphocytes.
Many human and mouse tumor antigens are normal, nonmutated tissue differentiation antigens. Consequently, immunization with these "self" antigens could induce autoimmunity. When we tried to induce immune responses to five mouse melanocyte differentiation antigens, gp100, MART-1, tyrosinase, and tyrosinase-related proteins (TRP) 1 and TRP-2, we observed striking depigmentation and melanocyte destruction only in the skin of mice inoculated with a vaccinia virus encoding mouse TRP-1. These mice rejected a lethal challenge of B16 melanoma, indicating the immune response against TRP-1 could destroy both normal and malignant melanocytes. Cytotoxic T lymphocytes specific for TRP-1 could not be detected in depigmented mice, but high titers of IgG anti-TRP-1 antibodies were present. Experiments with knockout mice revealed an absolute dependence on major histocompatibility complex class II, but not major histocompatibility complex class I, for the induction of both vitiligo and tumor protection. Together, these results suggest that the deliberate induction of self-reactivity using a recombinant viral vector can lead to tumor destruction, and that in this model, CD4(+) T lymphocytes are an integral part of this process. Vaccine strategies targeting tissue differentiation antigens may be valuable in cancers arising from nonessential cells and organs such as melanocytes, prostate, testis, breast, and ovary. (+info)
(2/331) Gene therapy study of cytokine-transfected xenogeneic cells (Vero-interleukin-2) in patients with metastatic solid tumors.
On the basis of compelling preclinical data in cats and dogs, we initiated a clinical gene therapy study in nine patients with advanced solid tumors using xenogeneic fibroblasts secreting human interleukin (IL)-2 (Vero-IL-2 cells). Cohorts of three successive patients with tumors accessible to computed tomography- or ultrasound-guided injection were treated repeatedly with 5 x 10(5), 5 x 10(6), or 5 x 10(7) Vero-IL-2 cells. The endpoints of the study were feasibility, toxicity, and the clinical and biological effects of this novel approach to immunotherapy of cancer. Histopathological, immunological, and molecular analyses were performed on biopsy specimens of tumors and blood samples before, during, and after treatment. Treatment was well tolerated, and toxicity consisted of transient fever in one patient and short-lived, mild itching and erythema in two others. One patient with soft-tissue sarcoma showed a reduction of >90% and >50% of the volume of two distant, noninjected metastases, lasting for 29+ and 26 months, respectively. Four other patients showed stabilization of their disease for 3-9 months; of these patients, one with melanoma developed marked vitiligo. We conclude that repeated injections of < or =5 x 10(7) Vero-IL-2 cells are feasible and safe in heavily pretreated patients with advanced solid tumors. An additional evaluation of an intratumoral application of Vero-IL-2 seems warranted. (+info)
(3/331) Serum levels of folic acid and vitamin B12 in Korean patients with vitiligo.
The association of vitiligo and pernicious anemia has been previously documented. The low levels of folic acid and vitamin B12 were thought to be related to vitiligo. To date, there have been very few reports about the serum levels of folic acid and vitamin B12 in patients with vitiligo. Using radioimmunoassay, we measured the serum levels of folic acid and vitamin B12 in 100 Korean patients with vitiligo. The mean serum levels of folic acid and vitamin B12 were 6.31 +/- 2.82 ng/ml and 630.25 +/- 230.94 pg/ml, respectively, in patients with vitiligo. These levels showed no significant difference compared to the normal control group, suggesting that folic acid and vitamin B12 do not appear to play a role in the pathogenesis of vitiligo. (+info)
(4/331) Combination immunotherapy of B16 melanoma using anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and granulocyte/macrophage colony-stimulating factor (GM-CSF)-producing vaccines induces rejection of subcutaneous and metastatic tumors accompanied by autoimmune depigmentation.
We examined the effectiveness of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) blockade, alone or in combination with a granulocyte/macrophage colony-stimulating factor (GM-CSF)-expressing tumor cell vaccine, on rejection of the highly tumorigenic, poorly immunogenic murine melanoma B16-BL6. Recently established tumors could be eradicated in 80% (68/85) of the cases using combination treatment, whereas each treatment by itself showed little or no effect. Tumor rejection was dependent on CD8(+) and NK1.1(+) cells but occurred irrespective of the presence of CD4(+) T cells. Mice surviving a primary challenge rejected a secondary challenge with B16-BL6 or the parental B16-F0 line. The same treatment regimen was found to be therapeutically effective against outgrowth of preestablished B16-F10 lung metastases, inducing long-term survival. Of all mice surviving B16-BL6 or B16-F10 tumors after combination treatment, 56% (38/68) developed depigmentation, starting at the site of vaccination or challenge and in most cases progressing to distant locations. Depigmentation was found to occur in CD4-depleted mice, strongly suggesting that the effect was mediated by CTLs. This study shows that CTLA-4 blockade provides a powerful tool to enhance T cell activation and memory against a poorly immunogenic spontaneous murine tumor and that this may involve recruitment of autoreactive T cells. (+info)
(5/331) Identification of epitopes on tyrosinase which are recognized by autoantibodies from patients with vitiligo.
The identification of tyrosinase autoantibodies in some patients with vitiligo has previously been reported. In this study we have determined the B cell epitopes on tyrosinase which are recognized by these autoantibodies. Deletion derivatives of tyrosinase cDNA were constructed and then translated in vitro with the concomitant incorporation of [35S]methionine into the protein products. The 35S-labeled tyrosinase derivatives were subsequently used in radioimmunoassays to investigate the reactivity of sera from five vitiligo patients. The epitope regions identified were: three in a central region of tyrosinase (amino acids 240-255, 289-294, and 295-300) and two others towards the C-terminal end of the protein (amino acids 435-447 and 461-479). Computer analysis of the potential B cell epitopes on tyrosinase revealed that the epitope regions recognized by the vitiligo sera were located in areas predicted to be highly antigenic. In addition, the centrally located antigenic regions (amino acids 289-294 and 295-300) had amino acid sequence homology to both tyrosinase-related protein-1 and -2. Thus, the epitopes on tyrosinase recognized by vitiligo patient sera are heterogeneous and include a region with homology to two related proteins which may explain the cross-reactivity previously noted between these antigens. (+info)
(6/331) Accumulation of identical T cells in melanoma and vitiligo-like leukoderma.
The cloning of genes encoding melanoma antigens has opened new possibilities for the treatment of patients with cancer; however, most tumor rejection antigens recognized by tumor infiltrating lymphocytes are the products of genes that are also expressed by normal melanocytes. Hence, a large set of antigenic determinants of the self have not induced self-tolerance and these peptide determinants furnish target structures for immune responses directed against tumors. The notion that the immunotherapeutic targets involved in cancer regression comprise normal differentiation antigens is stressed by the association between vitiligo-like leukoderma, due to destruction of normal melanocytes, and melanoma regression, due to destruction of cancer cells. Nevertheless, this is the first report to demonstrate by means of a new technique based on reverse transcription polymerase chain reaction and denaturing gradient gel electrophoresis, the presence of clonally expanded T cells with identical BV regions in areas of destruction of both normal and neoplastic cells. (+info)
(7/331) Genetic vaccination with "self" tyrosinase-related protein 2 causes melanoma eradication but not vitiligo.
"Self" melanocyte differentiation antigens are potential targets for specific melanoma immunotherapy. Vaccination against murine tyrosinase-related protein (TRP)-1/gp75 was shown recently to cause melanoma rejection, which was accompanied by autoimmune skin depigmentation (vitiligo). To further explore the linkage between immunotherapy and autoimmunity, we studied the response to vaccination with a related antigen, TRP-2. i.m. inoculation of plasmid DNA encoding murine trp-2 elicited antigen-specific CTLs that recognized the B16 mouse melanoma and protected the mice from challenge with tumor cells. Furthermore, mice bearing established s.c. B16 melanomas rejected the tumor upon vaccination with a recombinant vaccinia virus encoding trp-2. Depletion experiments showed that CD8+ lymphocytes and natural killer cells were crucial for the antitumor activity of the trp-2-encoding vaccines. Mice that rejected the tumor did not develop generalized vitiligo, indicating that protective immunity can be achieved in the absence of widespread autoimmune aggression. (+info)
(8/331) Analysis of the effect of endogenous viral genes in the Smyth line chicken model for autoimmune vitiligo.
The Smyth line (SL) chicken, an animal model for autoimmune human vitiligo, is characterized by a spontaneous posthatch pigment loss, determined to be the result of an autoimmune phenomenon. Because endogenous virus (EV) genes have been reported to be associated with a number of autoimmune diseases of human and animal models, we designed this experiment to investigate the role of EV in the SL vitiligo by using the complete sequence of Rous-associated virus-2 as a probe for EV. An F(2) resource population was developed by the matings of SL and parental control (BL) chickens. Linkage disequilibrium between vitiligo and EV was apparent (16.2-kb SacI fragment, P = 0.05 and a 19-kb HindIII fragment, P = 0.03). Methylation analyses revealed that the EV and endogenous avian retroviral (EAV) genes were methylated in both the SL and BL sublines of chickens; therefore, methylation does not appear to be responsible for the differences in the expression of vitiligo between SL and BL sublines. Expression of the EV genes correlated with the disease in vitiliginous SL101 birds and also in 5-Azacytidine-induced vitiliginous BL101 parental control chickens. Only one EV locus was detected in the unrelated Light Brown Leghorn control chickens (1q14) by in situ hybridization, whereas 3 EV loci were identified in SL101 and BL101 chickens (1p25, 2q26, and an unidentifiable microchromosome). Our observations indicate that EV genes may play a role in the induction of autoimmune vitiligo in the SL chicken model. (+info)