31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Zerebrospinale Nematodiasis bei sieben Ziegen

Clinical findings in seven goats affected with cerebrospinal nematodiasis are described. The animals originated from different parts of Switzerland. The disease occurred mainly in winter. The animals were admitted to the clinic because of progressive pelvic limb ataxia, recumbency, vestibular disease and circling. Clinical findings were complete or incomplete posterior paresis, pelvic limb ataxia, circling, reduced cutaneous sensation and proprioceptive deficits as well as cranial nerve reflexes deficits. The general condition was slightly reduced and the appetite was normal. In three goats predominance of mononuclear and eosinophilic cells in the cerebrospinal fluid was interpreted as typical findings for parasite infestation in the central nervous system. Histopathological changes and the finding of a nematode in cross sections in two affected animals confirmed the diagnosis. Infection with Elaphostrongylus cervi is discussed due to close contact with deer

Untersuchungen zur Behandung der zerebrospinalen Nematodiasis bei Ziegen

In 17 goats the therapeutical outcome of cerebrospinal nematodiasis, a parasitic infection in the central nervous system with the nematode Elaphostrongylus cervi, is described. The diagnosis was made on the basis of physical findings and cerebrospinal fluid eosinophilia. The therapy was based on the administration of a non-steroidal antiinflammatory drug (flunixin meglumine) and two anthelmintics (fenbendazol, ivermectin) for five days. The response to therapy was documented immediately and 30 days after therapy and by owners report up to 30 months. Eleven goats (64.7 %) showed an improvement of the neurological signs directly after therapy. Three had a complete recovery. Signs of a light and middle ataxie were still present in 6 and 2 goats, respectively. Six recumbent goats (35.3 %) had to be euthanasied because of a non-therapeutical response. This study has shown a clinical impression of successful use of flunixin meglumine, fenbendazole and ivermectin in goats with light to middle neurological signs. The goats could accommodate the remaining ataxia without showing a reduced production. Goats with high neurological deficits could not be successful treated based on the high degree of the neurological damage

Echocardiographic diagnosis of a cardiac fibrosarcoma in the right atrium of a sheep

This is a case report of a six-year-old female White Alpine sheep with a cardiac fibrosarcoma in the right atrium. Clinically, the sheep had right-sided cardiac insufficiency with tachycardia, engorgement of the jugular veins, brisket edema, and ascites. Chronic congestion of the liver resulted in increased hepatic enzyme activity. Based on clinical findings, a tentative diagnosis of endocarditis or pericarditis was made. Radiography of the thorax revealed hydrothorax. An echogenic mass was observed in the right atrium via echocardiography; it was interpreted as a tumor or thrombus. Ultrasonography of the abdomen revealed severe ascites and chronic congestion of the liver attributable to right-sided cardiac insufficiency. The clinical and sonographic findings were verified at post mortem. The mass in the right atrium was a pedunculated fibrosarcoma

Polyglobulie infolge Leberkarzinom bei Rind und Schaf

Polycythemia associated with hepatic carcinoma was diagnosed in a 10-year-old cow, an 8-month-old heifer and a 3-year-old sheep. The cow was referred to our clinic because of weight loss, reduced appetite, hematuria, marked reddening of the mucosa of the tear canal, oral cavity and vestibule and an increased hematocrit. Clinical examination also revealed injected scleral vessels. The erythrocyte count, the PCV, hemoglobin concentration and the activities of the hepatic enzymes were increased. Ultrasonographic examination revealed a very large liver with a focal echogenic lesion. Based on all findings, a diagnosis of polycythemia associated with a liver tumor, was made. The cow was slaughtered. Multifocal liver tumors were diagnosed histologically as hepatocellular carcinoma. The heifer and sheep had similar clinical and hematological findings. Hepatocellular carcinoma was diagnosed in the heifer and cholangiocellular carcinoma in the sheep. It was concluded that in all three patients, polycythemia was caused by hepatic carcinoma

Resistance to scrapie in PrP ARR/ARQ heterozygous sheep is not caused by preferential allelic use

Background: In sheep, susceptibility to scrapie, which is similar to human prion diseases such as Kuru and variant Creutzfeldt-Jakob disease (vCJD), is determined by prion protein (PrP) gene (Prnp) polymorphisms. Sheep with genotype ARQ/ARQ, denoting polymorphisms at codons 136, 154, and 171, are susceptible, whereas those with genotypes ARR/ARQ and ARR/ARR are resistant, indicating dominance of ARR over the ARQ allele. Aims: Based on familial CJD E200K, 129V, where preferential use of the 200E allele in EK heterozygous individuals confers resistance, heterozygous ARR/ARQ sheep were used to test the hypothesis that resistance is caused by preferential use of the ARR allele. Methods: After assessment of equivalent PrP expression across genotypes, allele use was analysed by sequencing reverse transcription polymerase chain reaction derived DNA clones containing the Prnp gene coding sequence. Results: The ARR to ARQ ratio was 1.1 in 133 clones, representing Prnp mRNA from three ARR/ARQ sheep, indicating equal use of both alleles. Conclusions: Dominance of the resistant associated allele in sheep scrapie involves mechanisms other than the absence of PrP derived from the disease associated ARQ allele

Borna disease in naturally infected cattle

Based on the immunohistochemical demonstration of viral antigen and on the histological brain lesions, Borna disease was diagnosed in a cow and a bull which had suffered from a severe, subacute progressive disorder of the central nervous system. Virus-specific antigen was characteristically localized in neurons, predominantly in the perikaryon and dendrites. In a serum sample available from one of the animals a Borna disease virus antibody titre of 1 in 80 was demonstrated. This is the first report of the natural disease in cattle

Untersuchungen zum Vorkommen von Elaphostrongylus sp. im Gehirn von Ziegen und Hirschen aus dem Kanton Tessin

The aim of the study was to examine the incidence of Elaphostrongylus cervi in the brain of sixty-five goats and fifty-nine red deer. The brains were also examined for neurohistological lesions. In the subdural space of the brain of five red deer a female nematode was recovered and identified as Elaphostrongylus sp. The histopathological examination of the brains revealed significantly more inflammatory, degenerative or combined lesions in goats than in red deer. Fourty-nine red deer and thirty-eight goats had no lesions in the brain. The lesions were minimal and consisted exclusively of nonpurulent infiltrations. No etiological agent could be found for the neurological changes. However Elaphostrongylus is able to produce similar lesions in specific as well as in nonspecific hosts and represents a likely cause for the histopathological findings