Biopsy tissue was fixed in 10% buffered formalin (Fisher Scientific) and processed for permanent paraffin embedding on a Leica ASP 300 tissue processor (Leica Microsystems); 5-m paraffin sections were stained with hematoxylin and eosin by using a Leica Autostainer XL

Biopsy tissue was fixed in 10% buffered formalin (Fisher Scientific) and processed for permanent paraffin embedding on a Leica ASP 300 tissue processor (Leica Microsystems); 5-m paraffin sections were stained with hematoxylin and eosin by using a Leica Autostainer XL. ovarian carcinoma patients also revealed that tumor destruction and severe inflammatory pathology could be dissociated, although further refinements are required to increase clinical responses and to minimize toxicity Xanthatin in this populace. The extent of therapy-induced tumor necrosis was linearly related to the natural logarithm of the ratio of intratumoral CD8+ effector T cells to FoxP3+ regulatory T cells (Tregs) in posttreatment biopsies. Together, these findings help clarify the immunologic and clinical effects of CTLA-4 antibody blockade in previously vaccinated patients and raise the possibility that selective targeting of antitumor Tregs may constitute a complementary strategy for combination therapy. 0.0001), but only weakly proportional to the intensity of intratumoral CD8+ T cells (slope 1.5, = 0.054) (Fig. 4 0.0001, and and data not shown). Although the antitumor response did not involve the generation of anti-CA-125 antibodies (data not shown), increased humoral reactions to NY-ESO-1, a cancer-testis antigen ectopically expressed in many ovarian carcinomas (26), were Xanthatin associated with therapeutic activity (Fig. 5 em C /em ). Open in a separate windows Fig. 5. CTLA-4 antibody blockade accomplishes the durable regression of advanced ovarian carcinoma in the absence of significant toxicity. ( em A /em ) CA-125 levels as a function of therapy. Small upward arrows indicate Col4a4 GVAX; downward arrows denote Ipilumimab infusions. ( em B /em ) Arrow indicates a large hepatic metastasis that underwent marked regression. ( em C /em ) MDX-010 augmented IgG antibodies to NY-ESO-1. Three additional subjects achieved stable disease of 6+ (ongoing), 4, and 2 months’ duration, as measured by CA-125 levels and radiographic criteria, in the absence of serious toxicities. The patient that designed Sweet’s syndrome and inflammatory colitis underwent a needle biopsy of pelvic disease, and this revealed extensive hemorrhagic tumor necrosis. Discussion Substantial evidence delineates CTLA-4 as a critical unfavorable regulator of antitumor immunity and a compelling target for cancer immunotherapy (5). However, CTLA-4 also is an essential mediator of immune homeostasis, as illuminated by the fatal lymphoproliferative disorder that arises in young CTLA-4-deficient mice (27, 28). In light of these complex activities, a major challenge for the clinical development of anti-CTLA-4-blocking monoclonal antibodies is usually to define a favorable therapeutic index that strikes an optimum balance between tumor immunity and inflammatory disease. The concordance of tumor regressions and serious toxicities in several previous trials of CTLA-4 blockade has raised the spectre that these two treatment effects might be linked (15C19). Indeed, because some molecularly defined malignancy antigens are nonmutated differentiation proteins expressed in normal tissues (29), tumor immunity and autoreactivity may be tightly associated in particular contexts. Notwithstanding this close relationship, malignancy genome sequencing experiments have Xanthatin uncovered a multiplicity of mutated gene products that derive from defects in tumor cell DNA repair mechanisms (30, 31). These alterations constitute neo-epitopes that may be presented in the context of MHC molecules as unique antigens for T cell recognition. If the host harbored sufficient reactivity to these mutated proteins, or other gene products aberrantly expressed in tumor cells, such as cancer-testes antigens (29), then less-intensive dosing and/or schedules of CTLA-4 blockade might be able to expand tumor-specific T cells preferentially, without compromising major homeostatic circuits that maintain tolerance to normal tissues. To explore this idea, we administered 3 mg/kg of Ipilumimab at 2- to 3-month intervals to patients who previously received GVAX. This autologous tumor-cell-based vaccination strategy consistently enhances specific and long-lasting immunity, which likely encompasses at least some tumor-restricted epitopes (4). Intriguingly, none of the 11 stage IV metastatic melanoma patients treated with this regimen manifested grade 3 or 4 4 inflammatory toxicities, as compared with 15%C25% of melanoma subjects that received higher levels of CTLA-4 blockade on other clinical trials (15C19). Nonetheless, larger numbers of melanoma patients will Xanthatin need.