The Influence of MHC and Immunoglobulins A and E on Host Resistance to Gastrointestinal Nematodes in Sheep

Gastrointestinal nematode parasites in farmed animals are of particular importance due to their effects on production. In Australia, it is estimated that the direct and indirect effects of parasite infestation cost the animal production industries hundreds of millions of dollars each year. The main factors considered by immunologists when studying gastrointestinal nematode infections are the effects the host's response has on the parasite, which immunological components are responsible for these effects, genetic factors involved in controlling immunological responses, and the interactions between these forming an interconnecting multilevel relationship. In this paper, we describe the roles of immunoglobulins, in particular IgA and IgE, and the major histocompatibility complex in resistance to gastrointestinal parasites in sheep. We also draw evidence from other animal models to support the involvement of these immune components. Finally, we examine how IgA and IgE exert their influence and how methods may be developed to manage susceptible animals

Variants of HCMV UL18 sequenced directly from clinical specimens associate with antibody and T-cell responses to HCMV

Around 80% of adults worldwide carry human cytomegaloviris (HCMV). The HCMV gene UL18 is a homolog of HLA class I genes and encodes a protein with high affinity for the NK and T-cell cytotoxicity inhibitor LIR-1. UL18 was deep sequenced from blood, saliva or urine from Indonesian people with HIV (PWH) (n = 28), Australian renal transplant recipients (RTR) (n = 21), healthy adults (n = 7) and neonates (n = 4). 95% of samples contained more than one variant of HCMV UL18, as defined by carriage of nonsynonymous variations. When aligned with immunological markers of the host’s burden of HCMV, the S318N variation associated with high levels of antibody reactive with HCMV lysate in PWH over 12 months on antiretroviral therapy. The A107T variation associated with HCMV antibody levels and inflammatory biomarkers in PWH at early timepoints. Variants D32G, D248N, V250A and E252D aligned with elevated HCMV antibody levels in RTR, while M191K, E196Q and F165L were associated with HCMV-reactive T-cells and proportions of Vδ2− γδ T-cells—populations linked with high burdens of HCMV. We conclude that UL18 is a highly variable gene, where variation may alter the persistent burden of HCMV and/or the host response to that burden

Sequencing of the viral UL111a gene directly from clinical specimens reveals variants of HCMV-encoded IL-10 that are associated with altered immune responses to HCMV

Human cytomegalovirus (HCMV) is a beta-herpesvirus carried by ~80% of adults worldwide. Acute infections are often asymptomatic in healthy individuals but generate diverse syndromes in neonates, renal transplant recipients (RTR), and people with HIV (PWH). The HCMV gene UL111a encodes a homolog of human interleukin-10 (IL-10) that interacts with the human IL-10 receptor. Deep sequencing technologies were used to sequence UL111a directly from 59 clinical samples from Indonesian PWH and Australian RTR, healthy adults, and neonates. Overall, 93% of samples contained more than one variant of HCMV, as defined by at least one nonsynonymous variation. Carriage of these variants differed between neonates and adults, Australians and Indonesians, and between saliva and blood leukocytes. The variant alleles of N41D and S71Y occurred together in Australian RTR and were associated with higher T-cell responses to HCMV pp65. The variant P122S was associated with lower levels of antibodies reactive with a lysate of HCMV-infected fibroblasts. L174F was associated with increased levels of antibodies reactive with HCMV lysate, immediate-early 1 (IE-1), and glycoprotein B (gB) in Australian RTR and Indonesians PWH, suggesting a higher viral burden. We conclude that variants of UL111a are common in all populations and may influence systemic responses to HCMV

The occurrence and severity of grass toxicoses in Australian alpaca (Vicugna pacos) herds

A survey of 108 alpaca producers registered with the Australian Alpaca Association examined the occurrence and severity of ‘staggers’ (a colloquial term embracing various diseases of the nervous system in animals, characterised by neck tremors and head nodding in the milder alpaca cases and a lack of coordination in moving, a staggering gait and frequent falling in severe cases) in Australian alpaca and the presence of four pasture grasses, during three production seasons in 2004–2006. There have been few studies on the susceptibility of alpaca to staggers and its effect on productivity and animal welfare. The survey found that 23% of alpaca producers had observed staggering animals, with Victoria and South Australia being the most severely affected states. Clinical signs of staggers were most frequent in January–March, with a mean duration of 3 months. Some animals showed clinical signs lasting up to 12 months. A strong correlation was found between the presence of perennial ryegrass (P &lt; 0.001) and phalaris (P &lt; 0.003) and the occurrence of staggers. Based on grass presence and the timing when staggers was observed, it was concluded that perennial ryegrass toxicosis was the main cause of staggers in alpaca. About 12% and 9% of alpaca grazing pasture containing perennial ryegrass exhibited staggers in the two full seasons for which data were collected. Herds with staggering animals were correlated with those exhibiting possible subclinical effects – heat sensitivity and ill-thrift (P &lt; 0.01) and reduced fertility (P &lt; 0.05) – of perennial ryegrass endophyte toxins. Results indicate that weanlings and cria are more likely to stagger than adults. Thirteen of the 15 mixed farms with staggering alpaca did not observe staggers in other livestock, suggesting that alpaca may be more sensitive to the causal toxins than sheep and cattle.</p

The occurrence and severity of grass toxicoses in Australian alpaca (Vicugna pacos) herds

A survey of 108 alpaca producers registered with the Australian Alpaca Association examined the occurrence and severity of ‘staggers’ (a colloquial term embracing various diseases of the nervous system in animals, characterised by neck tremors and head nodding in the milder alpaca cases and a lack of coordination in moving, a staggering gait and frequent falling in severe cases) in Australian alpaca and the presence of four pasture grasses, during three production seasons in 2004–2006. There have been few studies on the susceptibility of alpaca to staggers and its effect on productivity and animal welfare. The survey found that 23% of alpaca producers had observed staggering animals, with Victoria and South Australia being the most severely affected states. Clinical signs of staggers were most frequent in January–March, with a mean duration of 3 months. Some animals showed clinical signs lasting up to 12 months. A strong correlation was found between the presence of perennial ryegrass (P < 0.001) and phalaris (P < 0.003) and the occurrence of staggers. Based on grass presence and the timing when staggers was observed, it was concluded that perennial ryegrass toxicosis was the main cause of staggers in alpaca. About 12% and 9% of alpaca grazing pasture containing perennial ryegrass exhibited staggers in the two full seasons for which data were collected. Herds with staggering animals were correlated with those exhibiting possible subclinical effects – heat sensitivity and ill-thrift (P < 0.01) and reduced fertility (P < 0.05) – of perennial ryegrass endophyte toxins. Results indicate that weanlings and cria are more likely to stagger than adults. Thirteen of the 15 mixed farms with staggering alpaca did not observe staggers in other livestock, suggesting that alpaca may be more sensitive to the causal toxins than sheep and cattle.</p

A detailed experimental modal analysis of a clamped circular plate

A detailed study has been made of the natural frequencies and modal shapes of a thin steel discthat is clamped at the edges by two steel flanges. The aim was to determine how accuratelynumerical modeling could be used to predict the results and to investigate the possibility of any newexperimental observations even for this simple structure. A mechanical shaker and impact hammerwere used to excite the plate to obtain the frequency response function of the structure. The firsteight modal shapes at each of the resonant frequencies were then measured using laser scanningvibrometry. These results were compared with theoretical results obtained analytically andnumerically using PAFEC. While part of the existing understanding of the plate vibration wasconfirmed, significant differences were found in the values of the modal frequencies. Theexperimental data also demonstrated a dependence of the mode shape orientations and splitting ofdegenerated natural frequencies on the shaker position and properties of the flanges. This paperwill report on some interesting effects that need to be considered when doing such measurements and illustrate the risks of using numerical modeling without the use of experimental comparison