O19.6 Use of Surfactant Vesicles as a Potential Gonococcal Vaccine Delivery System to Generate Antibody Against Neisserial Lipooligosaccharide

Abstract

ΔlgtD (a strain that produces lacto-N-neotetraose LOS and a peptide (PADRE) that possesses the ability to bind to a large number of HLA class II molecules, inserted into a surfactant vesicle. TRIAD is a catanionic surfactant vesicle formulation and the resulting vesicle is stable at room temperature for years, unlike a typical liposome. TRIAD is so robust that it can be autoclaved without any appreciable loss of structural integrity. Results Using TRIAD that contained LOS and PADRE at a ratio of 10:1, and immunising with 2 μg of LOS equivalent, we were able to demonstrate that our vaccine induces a high titer anti-LOS antibody response, with the majority of the elicited antibody being IgG. Intraperitoneal immunisation of mice with our vaccine construct produced no observable adverse effects in mice, while intraperitoneal immunisation with equivalent amounts of purified LOS induced significant adverse effects. Conclusions Our surfactant vesicle platform possesses all of the advantages seen with traditional liposome formulations, without any of the inherent problems associated with liposome-mediated vaccines. This vaccine platform readily lends itself to further modifications in that it is possible to include additional neisserial proteins into the vaccine via a novel whole cell extraction protocol. We believe that this will allow us to generate a universal vaccine able to protect against all serotypes of N. meningitidis. Background The HIV epidemic has shown a considerable amount of heterogeneity, complicating the design and placement of prevention, intervention and treatment programmes. Place-based analyses providing specific information on pathogen prevalence, risk behaviours and other micro-level behaviours can help to target public health responses. Methods Data were from a cross-sectional survey of most-at-risk populations (MARPs) from Winnipeg, Canada. Respondents were recruited through respondent-driven sampling, and biological, behavioural and egocentric network data were collected. Respondents named locations where they frequented and where they engaged in risk behaviours, including the use of crack cocaine, injectable and non-injectable drug use, and solvents; and either seeking sex work clients or sex workers. Locations were geo-coded up to Statistics Canada dissemination areas. Two-mode network visualisation and centrality, degree, and betweenness measures were generated using UciNet (V.6). O.20 -Sexual partnerships and networksResults From a sample size of 600, nine locations were named by 10 or more respondents. The following results pertain only to these nine locations (N: 231). Locations corresponded to three "hot spots" in Winnipeg's inner and outer core areas. Across the sample, HIV and HCV prevalence was 9.8% and 51.5%, respectively. Prevalence varied considerably by location, ranging from 0% to 15% for HIV and 20% to 70% for HCV. Degree ranged from 0.054 to 0.330, closeness from 0.178 to 0.411 and betweenness from 0.054 to 0.521. No association between prevalence of HIV and HCV and network met...