Malaria parasites (Plasmodium spp.) infecting introduced, native and endemic New Zealand birds

Avian malaria is caused by intracellular mosquito-transmitted protist parasites in the order Haemosporida, genus Plasmodium. Although Plasmodium species have been diagnosed as causing death in several threatened species in New Zealand, little is known about their ecology and epidemiology. In this study, we examined the presence, microscopic characterization and sequence homology of Plasmodium spp. isolates collected from a small number of New Zealand introduced, native and endemic bird species. We identified 14 Plasmodium spp. isolates from 90 blood or tissue samples. The host range included four species of passerines (two endemic, one native, one introduced), one species of endemic pigeon and two species of endemic kiwi. The isolates were associated into at least four distinct clusters including Plasmodium (Huffia) elongatum, a subgroup of Plasmodium elongatum, Plasmodium relictum and Plasmodium (Noyvella) spp. The infected birds presented a low level of peripheral parasitemia consistent with chronic infection (11/15 blood smears examined). In addition, we report death due to overwhelming parasitemia in a blackbird, a great spotted kiwi and a hihi. These deaths were attributed to infections with either Plasmodium spp. lineage LINN1 or P. relictum lineage GRW4. To the authors’ knowledge, this is the first published report of Plasmodium spp. infection in great spotted and brown kiwi, kereru and kokako. Currently, we are only able to speculate on the origin of these 14 isolates but consideration must be made as to the impact they may have on threatened endemic species, particularly due to the examples of mortality

The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds

Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These ‘bill-tip organs’ allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill-tip organs and associated somatosensory brain regions are likely a result of similar ecological selective pressures, with inter-specific variations reflecting finer-scale niche differentiation

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

Development of the lung of the brushtail possum, Trichosurus vulpecula

The developing lung of the brushtail possum, Trichosurus vulpecula, was studied by light microscopy, and transmission electron microscopy was used to study the morphology of the conducting airways in the adult. Bronchi did not extend beyond the hilus of each of the six lobes of the lung, and lobules were supplied by major bronchioles. By 105 days post partum, bronchi and bronchioles were fully formed, coinciding with the emergence of mucosal associated lymphoid tissue (MALT), which preceded alveolar maturation by approximately 20 days. In the adult lung, goblet cells were rarely observed in the mucosal epithelium of bronchi, whereas Clara cells were present in the mucosa of all airways, increasing proportionately as the conducting and respiratory portions narrowed distally. Although the airways of the possum lung have a poorly developed mucociliary blanket, this may be compensated for by the large numbers of Clara cells and adequate supply of MALT

Sagittal sections of the brains of six species of birds examined in this study.

<p>Photomicrographs of sagittal sections stained with cresyl violet through the brain of six species of birds examined in this study. The top panel shows the principal sensory trigeminal nucleus (PrV) and the bottom panel the nucleus basorostralis (Bas). The broken black lines indicate the borders of each of the regions present in the sections. Brain sections are shown from North Island brown kiwi (<i>Apteryx mantelli</i>), bar-tailed godwit (<i>Limosa lapponica</i>), Eurasian woodcock (<i>Scolopax rusticola</i>), South Island oystercatcher (<i>Haematopus finschi</i>), black-winged stilt (<i>Himantopus himantopus</i>), and masked lapwing (<i>Vanellus miles</i>). Abbreviations: A: arcopallium, N: nidopallium, H: hyperpallium, E: entopallium, SPC: striatopallidal complex, M: mesopallium, C: caudal, R: rostral, D: dorsal, V: ventral. Scale bars; top panel = 1 mm, bottom panel = 2 mm.</p

3D reconstructions of brain structures in six species of birds examined in this study.

<p>3D reconstructions of the telencephalon (transparent), nucleus basorostralis (green), striatopallidal complex (blue) and the hyperpallium (red) in six species of birds. Models are shown in a lateral view in the top half of the panel and in a rostral view in the bottom half. Models are shown for North Island brown kiwi (<i>Apteryx mantelli</i>), bar-tailed godwit (<i>Limosa lapponica</i>), Eurasian woodcock (<i>Scolopax rusticola</i>), South Island oystercatcher (<i>Haematopus finschi</i>), black-winged stilt (<i>Himantopus himantopus</i>), and masked lapwing (<i>Vanellus miles</i>). </p

3D reconstructions of the bill-tips of five probe-foraging bird species.

<p>A1-4: the North Island brown kiwi (<i>Apteryx mantelli</i>), B1-4: Eurasian woodcock (<i>Scolopax rusticola</i>), C1-4: bar-tailed godwit (<i>Limosa lapponica</i>), D1-4: South Island oystercatcher (<i>Haematopus finschi</i>), and E1-4: black-winged stilt (<i>Himantopus himantopus</i>). Panel one shows a lateral view, panel two a dorsal view, panel three a ventral view, and panel four a rostral view. The dark grey structure represents the bone and the transparent structure the keratin. </p

Histological sections of North Island brown kiwi (<i>Apteryx mantelli</i>) and bar-tailed godwit (<i>Limosa lapponica</i>) bill-tips.

<p>A: Diagram of three coronal sections through a North Island brown kiwi bill, taken at: (1) 9 mm from the tip of the upper bill rhamphotheca (showing upper bill above, lower bill beneath); (2) 6 mm from tip of the upper bill rhamphotheca , sectioned through the sensory pad area forward of the tip of the rhamphotheca of the lower bill); (3) 3 mm from the tip of the upper bill rhamphotheca. Black areas represent the premaxilla and dentary bones. Dark grey shaded areas represent cross sections through the major nerves. Areas of soft tissue are shaded pale grey, the keratin and major blood vessels are left white. Herbst corpuscles (in 3) are white, with a central black line to represent the nerve axon. Bold lines indicate the outer surface of the keratin layer, finer lines indicate the junction between the dermal and keratin layers and the outlines of major blood vessels, nerves, and Herbst corpuscles. In (1), the premaxilla is perforated by the two nasal passages, bordered with bold lines and colored white. B: Sagittal section through a sensory pit in the North Island brown kiwi premaxilla, stained with Masson’s trichrome and C: a sensory pit in the bar-tailed godwit dentary, stained with haematoxylin and eosin. Abbreviations: N: nerves, B: bone. Examples of Herbst corpuscles are highlighted with white arrows. Scale bars = 100 µm.</p