Early school-leaving and occupations of native juveniles in Johannesburg.

Thesis submitted for Dr .Phi

Molluscan mega-hemocyanin: an ancient oxygen carrier tuned by a ~550 kDa polypeptide

<p>Abstract</p> <p>Background</p> <p>The allosteric respiratory protein hemocyanin occurs in gastropods as tubular di-, tri- and multimers of a 35 × 18 nm, ring-like decamer with a collar complex at one opening. The decamer comprises five subunit dimers. The subunit, a 400 kDa polypeptide, is a concatenation of eight paralogous functional units. Their exact topology within the quaternary structure has recently been solved by 3D electron microscopy, providing a molecular model of an entire didecamer (two conjoined decamers). Here we study keyhole limpet hemocyanin (KLH2) tridecamers to unravel the exact association mode of the third decamer. Moreover, we introduce and describe a more complex type of hemocyanin tridecamer discovered in fresh/brackish-water cerithioid snails (<it>Leptoxis</it>, <it>Melanoides</it>, <it>Terebralia</it>).</p> <p>Results</p> <p>The "typical" KLH2 tridecamer is partially hollow, whereas the cerithioid tridecamer is almost completely filled with material; it was therefore termed "mega-hemocyanin". In both types, the staggering angle between adjoining decamers is 36°. The cerithioid tridecamer comprises two typical decamers based on the canonical 400 kDa subunit, flanking a central "mega-decamer" composed of ten unique ~550 kDa subunits. The additional ~150 kDa per subunit substantially enlarge the internal collar complex. Preliminary oxygen binding measurements indicate a moderate hemocyanin oxygen affinity in <it>Leptoxis </it>(p50 ~9 mmHg), and a very high affinity in <it>Melanoides </it>(~3 mmHg) and <it>Terebralia </it>(~2 mmHg). Species-specific and individual variation in the proportions of the two subunit types was also observed, leading to differences in the oligomeric states found in the hemolymph.</p> <p>Conclusions</p> <p>In cerithioid hemocyanin tridecamers ("mega-hemocyanin") the collar complex of the central decamer is substantially enlarged and modified. The preliminary O₂binding curves indicate that there are species-specific functional differences in the cerithioid mega-hemocyanins which might reflect different physiological tolerances of these gill-breathing animals. The observed differential expression of the two subunit types of mega-hemocyanin might allow individual respiratory acclimatization. We hypothesize that mega-hemocyanin is a key character supporting the adaptive radiation and invasive capacity of cerithioid snails.</p

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

Nivolumab (Nivo) + Ipilimumab (Ipi) vs Platinum-Doublet Chemotherapy (Chemo) as First-line (1L) Treatment (Tx) for Advanced Non-Small Cell Lung Cancer (NSCLC): Safety Analysis and Patient-Reported Outcomes (PROs) From CheckMate 227.

Background: CheckMate 227 (NCT02477826) is a large phase 3 study of 1L nivo + ipi, nivo, or nivo + chemo vs chemo in advanced NSCLC. The study met its co-primary endpoint demonstrating significantly prolonged progression-free survival with nivo + ipi vs chemo in patients (pts) with tumor mutational burden ≥10 mutations/Mb. The safety profile of 1L nivo + low-dose ipi was consistent with previous reports. Additional detailed analyses may inform the management of immune-related adverse events. Methods: Pts (N = 1739) with chemo-naive, stage IV/recurrent NSCLC without known sensitizing EGFR/ALK mutations were randomized 1:1:1 to nivo (3 mg/kg Q2W) + ipi (1 mg/kg Q6W), nivo monotherapy (240 mg Q2W), or chemo for pts with ≥1% tumor PD-L1 expression and to nivo + ipi, nivo (360 mg Q3W) + chemo, or chemo for pts with < 1% tumor PD-L1 expression. Tx continued until disease progression or unacceptable toxicity for up to 2 yr. Safety and PROs were exploratory endpoints. Safety analyses included time to onset and resolution of select treatment-related adverse events (select TRAEs; those with a potential immunologic cause) and corticosteroid use. PROs were assessed using the Lung Cancer Symptom Scale and EQ-5D instruments. Results: Minimum follow-up was 11.2 mo. Median duration of therapy was 4.2 mo with nivo + ipi and 2.6 mo with chemo. Rates of any grade and grade 3–4 TRAEs were 75% and 31% with nivo + ipi, and 81% and 36% with chemo, respectively. TRAEs led to discontinuation in 17% of pts receiving nivo + ipi and in 9% of pts receiving chemo. Most frequent grade 3–4 select TRAEs in pts receiving nivo + ipi were hepatic (8%), endocrine (4%), skin (4%), pulmonary (3%), and gastrointestinal (2%). Median time to onset of select TRAEs ranged from 2–15 wk, and the majority resolved with corticosteroid use (median time to resolution was ≤10 wk). PRO results will be reported in the final presentation. Conclusions: In CheckMate 227, nivo + low-dose ipi was well tolerated in NSCLC. Toxicities were manageable with previously established tx algorithms, including corticosteroids

Nivolumab (Nivo) + platinum-doublet chemotherapy (Chemo) vs chemo as first-line (1L) treatment (Tx) for advanced non-small cell lung cancer (NSCLC) with

Background: CheckMate 227 (NCT02477826), a phase 3 study of 1L nivo + ipilimumab (ipi), nivo, or nivo + chemo vs chemo in advanced NSCLC, met its co-primary endpoint of prolonged progression-free survival (PFS) with nivo + ipi vs chemo in patients (pts) with tumor mutational burden ≥10 mutations/Mb. Identifying effective tx for pts without known predictive biomarkers remains an unmet need. Prior studies suggest addition of chemo to anti–PD-(L)1 tx can improve outcomes in an unselected pt population, although benefit is most pronounced in pts with higher tumor PD-L1 expression. We report results for nivo + chemo vs chemo in pts with < 1% tumor PD-L1 expression. Methods: Pts (n = 550) with chemo-naive, stage IV/recurrent NSCLC, no known sensitizing EGFR/ALK mutations, and < 1% tumor PD-L1 expression were stratified by tumor histology and randomized 1:1:1 to nivo 3 mg/kg Q2W + ipi 1 mg/kg Q6W, nivo 360 mg Q3W + chemo, or chemo (optional pemetrexed maintenance after chemo for nonsquamous [non-SQ] NSCLC). Pts were treated up to 2 yr. A descriptive analysis was performed for the secondary endpoint of PFS for nivo + chemo vs chemo in pts with < 1% tumor PD-L1 expression. No alpha was allocated for this analysis. Results: Baseline characteristics were balanced between nivo + chemo (n = 177) and chemo (n = 186) arms. PFS was improved with nivo + chemo vs chemo (HR = 0.74 [95% CI: 0.58, 0.94]; minimum follow-up 11.2 mo; descriptive comparison). PFS benefit with nivo + chemo was observed across most subgroups. Among histologic subgroups, benefit was more pronounced in non-SQ (HR = 0.68) relative to SQ NSCLC (HR = 0.92). Rates of any grade tx-related adverse events leading to discontinuation were 13% with nivo + chemo and 14% with chemo. Conclusions: 1L nivo + chemo improved PFS vs chemo in pts with advanced NSCLC and < 1% tumor PD-L1 expression, and was well tolerated. Results are encouraging in this analysis, which includes only pts with < 1% PD-L1. CheckMate 227 Part 2 (ongoing) is evaluating nivo + chemo vs chemo irrespective of PD-L1 expression and will further inform benefit from this combination across different subgroups of NSCLC