Positioning Quebec ORF5 sequences of porcine reproductive and respiratory syndrome virus (PRRSV) within Canada and worldwide diversity

Sequencing of ORF5 gene is widely used and considered essential for diagnostics and control of porcine reproductive and respiratory syndrome (PRRS) in Canada. The objective of this study was to position Quebec ORF5 sequences of PRRS virus within Canada and worldwide diversity. Overall, 76.8% of the 5204 sequences gathered from Quebec (n = 5031), Ontario (n = 151) and Manitoba (n = 18) were classified into one of 34 genetic clusters defined as groupings including ≥15 sequences and having ≥70% rapid bootstrap support value from a maximum likelihood (ML)-phylogeny. Following the addition of PRRSV 2 international reference dataset from Shi et al. (2010), the most predominant lineages in our dataset were wild-type 1 and vaccine-like 5.1 (MLV) and 8.9 (ATP). No strains or only a very few (1 or 2) were assigned to lineages 1.3–1.5, 3, 4, 5.2, 6, 7 or 9. Most wild-type clusters (97%) detected in a dataset from Canada did not include any sequence from the international reference dataset. It might reflect recent subpopulations that were absent at the time of Shi's publication. As an example, cluster #25 first appeared in 2007, but since then had expanded considerably and is now the most prevalent wild-type cluster found in Quebec. A total of 117 RFLP patterns were identified and those were poorly correlated with genetic clusters based on phylogeny. Factors modulating PRRSV diversity such as pig movement that occurred within and between provinces should be further investigated in a perspective of disease control.     

ONRAB® oral rabies vaccine is shed from,but does not persist in,captive mammals

ONRAB® is a human adenovirus rabies glycoprotein recombinant vaccine developed to control rabies in wildlife. To support licensing and widespread use of the vaccine, safety studies are needed to assess its potential residual impact on wildlife populations. We examined the persistence of the ONRAB® vaccine virus in captive rabies vector and non-target mammals. This research complements work on important rabies vector species (raccoon, striped skunk, and red fox) but also adds to previous findings with the addition of some non-target species (Virginia opossum, Norway rats, and cotton rats) and a prolonged period of post vaccination monitoring (41 days). Animals were directly inoculated orally with the vaccine and vaccine shedding was monitored using quantitative real-time PCR applied to oral and rectal swabs. ONRAB® DNA was detected in both oral and rectal swabs from 6 h to 3 days post-inoculation in most animals, followed by a resurgence of shedding between days 17 and 34 in some species. Overall, the duration over which ONRAB® DNA was detectable was shorter for non-target mammals, and by day 41, no animal had detectable DNA in either oral or rectal swabs. All target species, as well as cotton rats and laboratory-bred Norway rats, developed robust humoral immune responses as measured by competitive ELISA, with all individuals being seropositive at day 31. Similarly, opossums showed good response (89% seropositive; 8/9), whereas only one of nine wild caught Norway rats was seropositive at day 31. These results support findings of other safety studies suggesting that ONRAB® does not persist in vector and non-target mammals exposed to the vaccine. As such, we interpret these data to reflect a low risk of adverse effects to wild populations following distribution of ONRAB® to control sylvatic rabies.     

Inactivated influenza vaccine formulated with single-stranded RNA-based adjuvant confers mucosal immunity and cross-protection against influenza virus infection

Influenza vaccination is considered the most valuable means to prevent and control seasonal influenza infections, which causes various clinical symptoms, ranging from mild cough and fever to even death. Among various influenza vaccine types, the inactivated subunit type is known to provide improved safety with reduced reactogenicity. However, there are some drawbacks associated with inactivated subunit type vaccines, with the main ones being its low immunogenicity and the induction of Th2-biased immune responses. In this study, we investigated the role of a single-stranded RNA (ssRNA) derived from the intergenic region in the internal ribosome entry site of the Cricket paralysis virus as an adjuvant rather than the universal vaccine for a seasonal inactivated subunit influenza vaccine. The ssRNA adjuvant stimulated not only well-balanced cellular (indicated by IgG2a, IFN-γ, IL-2, and TNF-α) and humoral (indicated by IgG1 and IL-4) immune responses but also a mucosal immune response (indicated by IgA), a key protector against respiratory virus infections. It also increases the HI titer, the surrogate marker of influenza vaccine efficacy. Furthermore, ssRNA adjuvant confers cross-protective immune responses against heterologous influenza virus infection while promoting enhanced viral clearance. Moreover, ssRNA adjuvant increases the number of memory CD4⁺ and CD8⁺ T cells, which can be expected to induce long-term immune responses. Therefore, this ssRNA-adjuvanted seasonal inactivated subunit influenza vaccine might be the best influenza vaccine generating robust humoral and cellular immune responses and conferring cross-protective and long-term immunity.     

HRV的最大李雅普诺夫指数估计

对心率变异性(HRV)进行了研究,比较了心率正常者与心率失常者HRV之间的最大李雅普诺夫指数上的差别。人在正常状态和病理状态下的HRV信号最大李雅普诺夫指数是不同的,当出现病理心血管事件时,指数α减少,因此李雅普诺夫指数可作为人体是否异常或处于何种异常状态的特征刻画指标,本文心率正常者HRV信号的最大李雅普诺夫指数为0.45907,心率不齐者的最大李雅普诺夫指数是0.41472。它们均为混沌信号,但是处于心率不齐状态的节律混沌程度明显比处于心率正常状态的节律混沌程度低。     

禽流感H9亚型血凝素单克隆抗体的研制和初步应用

目的：获得特异针对禽流感H9亚型血凝素单克隆抗体。方法：以H9N2亚型病毒制成疫苗免疫BALB／c小鼠，取脾细胞与SP2／0细胞融合，取细胞上清用HI筛选。结果：共获得9株稳定分泌针对血凝素蛋白抗体的杂交瘤细胞；经广谱性和特异性鉴定，所有单抗株均能与所有检测的82株不同年代不同地方不同禽源H9亚型流感病毒大部分分离株反应，且所有单抗株均不与非AIV-H9病毒反应，而其中一株（8E6）能与所有检测的H9亚型病毒株反应。进行Western blot分析显示，其中8株单抗能与AIV的Mr为75000处反应，表明是针对AIVH9HA的单抗。结论：本试验获得9株广谱性特异性很好的单抗，特别是8E6株；这些单抗株为以后作病毒抗原性位点分析、临床检测和流行病学调查提供了良好试剂。