Sarah Clark

International Seroepidemiology of Adenovirus Serotypes 5, 26, 35, and 48 in Pediatric and Adult Populations

Recombinant adenovirus serotype 5 (rAd5) vaccine vectors for HIV-1 and other pathogens have been shown to be limited by high titers of Ad5 neutralizing antibodies (NAbs) in the developing world. Alternative serotype rAd vectors have therefore been constructed. Here we report Ad5, Ad26, Ad35, and Ad48 NAb titers in 4381 individuals from North America, South America, sub-Saharan Africa, and Southeast Asia. As expected, Ad5 NAb titers were both frequent and high magnitude in sub-Saharan Africa and Southeast Asia. In contrast, Ad35 NAb titers proved infrequent and low in all regions studied, and Ad48 NAbs were rare in all regions except East Africa. Ad26 NAbs were moderately common in adults in sub-Saharan Africa and Southeast Asia, but Ad26 NAb titers proved markedly lower than Ad5 NAb titers in all regions, and these relatively low Ad26 NAb titers did not detectably suppress the immunogenicity of 4×10(10)vp of a rAd26-Gag/Pol/Env/Nef vaccine in rhesus monkeys. These data inform the clinical development of alternative serotype rAd vaccine vectors in the developing world.

Multiple Innate Immune Pathways Contribute to the Immunogenicity of Recombinant Adenovirus Vaccine Vectors

ABSTRACT The innate immune pathways that contribute to the potent immunogenicity of recombinant adenovirus (rAd) vaccine vectors remain largely undefined. Previous studies assessing innate immunity triggered by vaccine vectors have largely focused on in vitro studies involving antigen-presenting cells and on early in vivo inflammatory responses. Here, we systematically explore the Toll-like receptor (TLR) signaling requirements for the generation of cellular immune responses by intramuscular immunization with common and alternative serotype rAd vectors in mice. Antigen-specific CD8+ T-lymphocyte responses elicited by these rAd vectors were significantly diminished in MyD88−/− mice but not in TRIF−/− or TLR3−/− mice, suggesting the importance of MyD88-dependent TLR signaling. However, the absence of each individual TLR resulted in minimal to no effect on vaccine-elicited cellular immune responses. Moreover, responses were not diminished in IL-1R−/− or IL-18R−/− mice. These data suggest that rAd vectors engage multiple MyD88-dependent signaling pathways, none of which are individually critical; rather, they are integrated to contribute to the potent immunogenicity of rAd vectors. Stimulation of multiple innate immune mechanisms may prove a generalizable property of potent vaccines, and this strategy could be harnessed in the development of next-generation vaccine vectors and adjuvants.

Protective Efficacy of a Single Immunization of a Chimeric Adenovirus Vector-Based Vaccine against Simian Immunodeficiency Virus Challenge in Rhesus Monkeys

ABSTRACT Rare serotype and chimeric recombinant adenovirus (rAd) vectors that evade anti-Ad5 immunity are currently being evaluated as potential vaccine vectors for human immunodeficiency virus type 1 and other pathogens. We have recently reported that a heterologous rAd prime-boost regimen expressing simian immunodeficiency virus (SIV) Gag afforded durable partial immune control of an SIV challenge in rhesus monkeys. However, single-shot immunization may ultimately be preferable for global vaccine delivery. We therefore evaluated the immunogenicity and protective efficacy of a single immunization of chimeric rAd5 hexon hypervariable region 48 (rAd5HVR48) vectors expressing SIV Gag, Pol, Nef, and Env against a homologous SIV challenge in rhesus monkeys. Inclusion of Env resulted in improved control of peak and set point SIV RNA levels following challenge. In contrast, DNA vaccine priming did not further improve the protective efficacy of rAd5HVR48 vectors in this system.

TLR4 Ligands Augment Antigen-Specific CD8+ T Lymphocyte Responses Elicited by a Viral Vaccine Vector

ABSTRACT Toll-like receptor (TLR) ligands are critical activators of innate immunity and are being developed as vaccine adjuvants. However, their utility in conjunction with viral vector-based vaccines remains unclear. In this study, we evaluated the impact of a variety of TLR ligands on antigen-specific CD8+ T lymphocyte responses elicited by a recombinant adenovirus serotype 26 (rAd26) vector expressing simian immunodeficiency virus Gag in mice. The TLR3 ligand poly(I:C) suppressed Gag-specific cellular immune responses, whereas the TLR4 ligands lipopolysaccharide and monophosphoryl lipid A substantially augmented the magnitude and functionality of these responses by a MyD88- and TRIF-dependent mechanism. These data demonstrate that TLR ligands can modulate the immunogenicity of viral vaccine vectors both positively and negatively. Moreover, these findings suggest the potential utility of TLR4 ligands as adjuvants for rAd vector-based vaccines.

Quality of life in epilepsy in Bhutan

PURPOSE To assess the quality of life in epilepsy (QOLIE) among adults in the lower middle-income country of Bhutan and assess the potential demographic and clinical associations with better QOLIE. METHODS People with clinically diagnosed epilepsy were prospectively enrolled at the Jigme Dorji Wangchuck National Referral Hospital in Thimphu (2014-2015). Regression models were constructed to assess the potential impact of age, sex, residence in the capital city, wealth quintile, educational attainment, seizure in the prior year, seizures with loss of consciousness, self-reported stigma score, and need for multiple antiepileptic drugs. RESULTS The mean Bhutanese 48.4/100 ± 17.3 [corrected] score among 172 adults (mean age 31.1 years, 93 female) was 48.9/100±17.7. Younger age, lower educational attainment level, and increased self-perceived stigma were each observed to have an independent, negative association with QOLIE (p<0.05), while a patients wealth quintile, sex, seizure frequency, seizure type and number of antiepileptic drugs were not. Education appeared to be most strongly associated with QOL at the high school and college levels. CONCLUSIONS There are potentially modifiable associations with low QOLIE. Addressing the educational level and self-perceived stigma of PWE may have an especial impact. The low QOLIE in Bhutan may reflect cultural approaches to epilepsy, health services, or other factors including those outside of the health sector.

Corrigendum to “Quality of life in epilepsy in Bhutan” [Seizure 39 (2016) 44–48]

The authors regret that there were errors in the final published article. The corrected version is given here: The QOLIE-31 score in the abstract should be 48.4/100 17.3. The first sentence under the Results heading should read: “The QOLIE score in Bhutanese PWE was low (median 48.5, mean 48.4, standard deviation 17.3), with a statistically significantly different overall QOLIE-31 score between male and female participants.” The last sentence under the first paragraph of the Results heading should read: “Of the seven subscales, the seizure worry score had the lowest scores (mean 33.1, SD 24.0). The authors would like to apologise for any inconvenience caused.