 Hello. So as some of you might know, I'm not Dr. Finley, but it's okay. So he sends his regards So he couldn't make it last minute today. So I'm here. I'm a graduate student in the lab working in this area So I'd just like to first thank the organizers, Lita and others for the invitation and Also I'm I'm the one of the ones working here in microbiome and vaccines and we're just still in the early days In this area But I just like to present more of a conceptual talk of you know, where the field is and you know, possibly where it's going So I don't really think I need to convince this audience of this But unfortunately, there are some people that still need to be convinced of this that vaccines work quite simply So I think this is best viewed through when you look at the disease incidents of things such as measles mumps rubella before Vaccines and now after vaccines. It's just a you know a dramatic decrease But I'd just like to point out You know, there's a relative lack of licensed effective oral vaccines, particularly for bacterial infections So we do have some oral vaccines For rotavirus, you know, so there's rhodorix and rhodotac. Of course the polio vaccine But in terms of developing oral vaccines for diarrheal diseases Such as salmonella E. Coli Shigella and these diseases remain like a significant worldwide health issue There's still tens of millions of people in the developing world that die of these diseases and I think that This is best viewed here through disability life years lost So the amount of the burden in hospitals of treating these patients And uh and that accounts for around 15 percent of that is diarrheal diseases And the so the gold standard for this is the development of a vaccine Now we know for these diarrheal diseases, particularly we can use antibiotics But has julian davis nicely pointed out with the increasing incidence of antibiotic resistance You know, we're really trying to develop, you know oral vaccines that are easy to use and effective for these Diseases, but really the problem in the field Many people have been looking at this is there's really a poor understanding of the determinants of protective gut immunity And there's another phenomenon which i'll get into which uh david mills kind of alluded to as well as vaccines have reduced efficacy And immunogenicity in developing countries Specifically areas with poor sanitation Now we've had three days of Great background into everything the microbiota does to the host And uh, I think we know now Um, there are specific bacterial species that actually influence our immune system So I don't need to convince you of this. So these are the three, you know, best characterized examples in the field There's a Bacteroides fragilis secreting polysaccharide A So sarcus mesmanians group has looked at that inducing t regulatory cells Kenyon Honda has done some great work on specific clostridial species that can induce t regulatory cells And uh segmentus filamentous bacteria can lead the proliferation of th 17 cells I don't think I need to convince you that shifts in the microbiota Can actually influence Immune development and this is also can be viewed through germ free mice, which we know Have reduced numbers in size of pairs patches and really just a lack of gut associated lymphoid tissue Reduced levels of class switching to ig g and iga antibodies Decreased number of cd4 positive t cells and these mice don't Develop tolerance, but if you come into a germ free mouse with with a complex Host adapted microbiota, we can now restore the intestinal immune system So we need our microbiota for immune development So uh our lab, um posed a question a few years back, you know, given this the profound impact the microbiota has On the development of our immune system, especially early in life Should human microbiome be considered when we're developing these vaccines? So our lab has been particularly interested in developing oral vaccines For a diarrheal pathogen such as E. Coli. We have a vaccine for cattle. We're currently working on oral non-typhoidal vaccine for salmonella So given that we're working on this and we're also um researching the microbiome field Um We pose this question and still is the early days. There's really not too much data But I know there are groups working on this and we wanted to ask the question Could our newfound knowledge of the impacts of the gut microbiota be a missing link to improve oral vaccine efficacy and develop more effective oral vaccines So this is phenomena, uh, there's really a large body of evidence in the literature Suggesting that uh oral vaccines specifically polio, uh rotavirus um cholera, uh e-tech show A greatly reduced efficacy in developing countries specifically regions with poor sanitation compared to developed countries a couple examples Using the oral cholera vaccine as a tool to show this as the nicaraguan children have blunted antibody responses compared to those in Sweden and uh, there's a study by myron the vines group a few years back where they showed that Kids um with small intestinal bacteria overgrowth also had blunted antibody responses So but we also know that you know these this phenomena of blunted vaccine responses to oral vaccines Um, you know could be due to a wide variety of issues for people living these areas of the world Uh, you know, they live in these areas where they have increased antigen exposure So if you come in with an oral antigen, um, the immune system might react differently than they would here That's sort of the hygiene hypothesis idea Of course, um, you know, a lot of these people are malnourished and we know that you know, this Is uh leads to nutrient deficiencies such as vitamin a so what david mills talked about Um, you know, there's hundreds of millions of people who are vitamin a deficient in many areas of the world And you know, that's an important pathway In many immune pathways the retinoic acid pathway and also zinc is quite important um, you know, these people use less antibiotics And of course, I think the elephant in the room as well is that a parasite So they really have a greater, uh, parasite burden and they're got compared to uh here in more developed countries However, I'd say that all of these changes can actually feed into your microbiota composition um, so uh And this is a study that's actually been cited numerous times over the conference It's one of the first studies to really look at the microbiota composition in Comparing african, uh cohort to a cohort in the european union So, uh, what they saw is in the Burkina Faso There's actually an increase in prevetella and actually, uh microbes that can Degrade carbohydrates and then in the european union There's really an increase in the amount of let's say clostridialias or bactoid deadies that are um Involved in lipid metabolism. So we know now that diet can actually shift microbial assemblages And there's really a difference in microbial assemblage in some of these areas of the world And this sort of phenomenon of more prevetella in the gut has been seen in other studies And we also know from some great work by uh, jeff gordon's group that Mount nutrition can actually shift the microbial community As well, so could the microbiota be implicated as to why vaccines show reduced efficacy in Developing countries and that's still an open question that I think many people are interested in What there have been some studies, um, you know, how can we solve this right? So We're modulating the flora to try to use, you know, prebiotics or probiotics as adjuvants per se to, you know, actually help Some of these vaccine responses. So there's been some small studies mostly in mice where they used, um Lactobacillus and strains of Bephidobacterium to actually improve rotavirus color vaccine and a seminalityphe vaccine efficacy As well as prebiotics fructal gliosaccharide mixes to improve Seminella vaccine and influenza vaccine responses. So there's some Evidence that this might be important So the question is, you know, can we manipulate the microbiota to improve? vaccine responses and Similarly, they're I've been talking mostly about oral vaccine, but there is some evidence that in parental vaccines Probiotics can be important as well Particularly early in life. So I think there's been a few great presentations that have shown the difference in microbiota after a c-section Or versus a vaginal delivery Or formula feeding versus breast milk And this can actually decrease your probiotic microorganisms And you know, what the effect this has on the vaccine responses Remains to be seen. However, has David just suggested, you know, this could be an important thing to realize in these kits But there's sort of still in the early days. There's really a lack of long-term follow-up studies And a lot some studies do show variable effectiveness. You know, it's important to choose the right probiotic strain and some mechanisms are unclear, but I think David gave a great talk and about, you know, possibly the need for symbiotics So this could help with the colonization efficiency and as I've seen there's no studies as of yet where they've actually used more of a symbiotic approach In terms of improving vaccine responses. So this could be an interesting area So another sort of paradigm I'd like to touch on is this idea that, you know, we could actually maybe use probiotics to deliver Vaccine antigens themselves. So there's some talk yesterday about, you know, there's this need to genetically manipulate some of these anaerobes and we need to kind of develop the tools of that and one of the translational applications of that could be actually getting these probiotics to Actually display some vaccine antigens so we can get elective acilis possibly and you know Deliver some vaccine antigens and have it colonized in the host So there's a proof of concept study where they did this in a lactive acilis lactic strain So this is just proof of concept, but they made it express a listeria internalin And they show that it actually internalizes and delivers the gene in the small intestine So this could be, you know, a way to deliver some sort of a dna based vaccine However, there's no real data on the efficacy in animals or humans as it yet So this is just sort of a concept that could be thought of but I think it's also important to point out with this concept That it could be relevant to what we now know about IGA responses So Andrew McPherson's group has done some great work Looking at IGA and what they've seen is that you actually constant exposure of oral antigen to elicit lifelong IGA responses So if you come in with an oral antigen and look at a specific IGA years later, it will be gone But if you actually constantly expose the host to that antigen, it will help mucosal IGA responses So there's a couple of studies I also want to highlight and these are actually from groups here in Maryland Marcelo Stein and Claire Fraser. So they've done some stuff. This is work in macaques where they've looked at the microbiota and vaccines and they looked at macaques from different geographical regions and they had different assemblages of microbiota and they came in with with an oral shigella vaccine And they showed that this vaccine actually really didn't have a change on the microbiota However, after vaccination different macaques responded differently to infection So there's I actually got shigellosis only in certain macaques compared to others So I won't really dive into the details of the study I think Claire is here today. So if you want to ask her but I just wanted to point out that, you know, maybe we need to take the impact of the microbiota into consideration in some of these vaccine trials, you know, not all macaques are the same, of course, and not all humans are the same and so another study from the same group is Looking in humans at oral typhoid vaccination. So there's an oral typhoid strain Ty 21a And This is a great study But what just one thing I wanted to point out is they saw the same thing no real change in the microbiota due to the vaccine However, they split up the cell mediated response Into a multi phasic response or late responders And what they did see is if you had a more diverse microbiota You actually had a greater multi phasic cell mediated response to this vaccine And this was actually shown more in the cluster the alleys groups So this kind of, you know, this these are correlative studies, of course But they kind of hint to the importance of our microbiota in in oral vaccine responses So some of the work Our lab is doing we're actually working in murine models and we're testing different antibiotics To mice early in life or adult mice and we're coming in with a different Either a seminella peptide vaccine or ovalbumin type mock vaccination Orally and then looking at the microbiota and looking at specific antibody and T cell mediated readouts to see whether Different microbiota shifts could actually shift our immune response to vaccines So we're still in the early days of this work But some of the changes that we've seen is but have been in IgA responses So we know we need diverse microbial exposure To get proper levels of IgA. So in mice treated with vecomycin From birth they have a reduced amount of colonic T regulatory cells Which have been known to be helper cells for IgA responses. So we see a reduction in In the IgA response to these The vaccine and but interestingly when we took the adult mice and we treated with vecomycin We actually saw an increase in the amount of IgA specific to the vaccine And we think this is possibly a permeability issue. So that you know from adulthood They do have a developed immune system But then the antigen can actually cross the barrier and be seen by a systemic immune system Which is also important in oral vaccination But you know, we're still in the early days And I think this conference has done a fabulous job of really addressing a lot of the sort of gaps needs and challenges in the field And definitely in the area of microbiome vaccines such as such in the early days There's a ton of challenges And this is something that a lot of people have touched on but I'll just reiterate Is that of course people working with vaccines know that you know, you want to get the vaccine to humans as quickly as possible There's so many examples of vaccines that fail Or that work in animal models that actually turn up to not work in humans So humans are much more relevant But of course when we're looking at shifts in the microbiota and correlating it to vaccine responses As I it's just it's correlative and you can't actually dive into the mechanism Whereas if you're using an animal model, whether it be a murine or in macaques You know, this might have more of a poor translation To humans, however, we can be more mechanistic with the function. So I think we still need a balance of both And something that I know is an issue in these vaccine trials in humans is that You know, we take the feces And we look at the microbiota composition and then we correlate that to vaccine responses But fecal microbiota is just really the flow through of all the microbiota And you really lose that sort of spatial distribution and longitudinal distribution from the small intestine to the colon That some people have been talking about and you just kind of get this Community but we're not really sure, you know, which ones are actually hearing to the mucosal surfaces And I would argue that these ones would be more Immunologically relevant and and just basically the same point. So it's difficult in humans to study these mucosal associated microbiota You can take biopsies of but there are like ethical Considerations there So there's this significant gap between animal and human studies And what we need and I know there's some groups interested in this is mice with humanized immune systems So you can actually take a mouse and give it sort of a more human based immune system And now maybe we can come in with more of a human Microbiota and this might be more translational to vaccine research now, you know, I think some scientists scientists groups would play Pay a pretty penny For actually maybe a germ free mouse with a humanized immune system and then come in with a humanized microbiota And this could be sort of a need in the field for the future So for the last part of the talk, I'm going to shift gears And talk about something completely different Still related to vaccines and microbiota But this sort of idea is can we actually use vaccines to target specific species of the microbiota? And this might be a need As we begin to identify some of the keystone species or pathobionts or troublemakers per se in the gut So we have, you know, probiotics that come in and try to tame those But we could also maybe start to target them specifically because right now we really only have blunt tools at our disposal to do so With lots of side effects. So that's such of course like dietary changes antibiotics Prebiotics or even phage therapy Um So I think this is one study that Explains this is that in periodontist. There's one species porphyromonas gingivalis That just the presence of this organism is kind of a troublemaker per se So it influences the microbiota in the oral Cavity around it to become more virulent And it's quite a low abundance organism, but it seems to have profound effects in this Disease, um, so, you know, can we target this and there have been groups There's one that looked at periodontal vaccine. So can we target? You know parts and constituents of the oral cavity to try to get rid of these, you know pathobionts So they looked at um an outer membrane porin form a From the species fusive bacterium nucleotom and they by targeting it They kind of got rid of this bridge between how porphyromonas Enables itself to form biofilms and cause gingivitis. So this worked in a mouse model of gingivitis So and there's some more examples where we can maybe target pathobionts with vaccines like the homophilus influenza b vaccine Which has virtually eliminated this homophilus from the ferronegial microbiota So before the vaccine there was a secondary carriers about three to five percent But now it's replaced by a less virulent homophilus strains Um, also striptococcal pneumonia The valent vaccine Has seen a 77 percent decrease in disease and this has been replaced by other non vaccine strains that appear to be less virulent So this opens up some questions, you know, can we target specific microbiota with vaccines? Um, and you know, maybe they'll be replaced with sort of less virulent closely related species Now I realize that you know anytime you see sort of autism and vaccines together in a sentence it It makes me cringe and it makes a scientist cringe But you know, this is sort of a more of a provocative slide to say that, you know, there's some uh evidence coming out now That actually autism is a is a gi disease So 90 autistic kids have some sort of gi irritation And there's been studies that show there's this clostridium boltae Or there's other clades of clostridium that actually produce toxins that could go systemic into the bloodstream and possibly have neurological effects So possibly could we actually, you know target some of these? Pathobioids with some sort of a vaccine and sort of quell that those effects now There is some talk that this autism could also be sort of a gut permeability issue as well So can we sort of target some of those metabolites that are produced and you know and try to get rid of Some of those effects, but this is something that's sort of very new um And there's also a group at guelph Who is looking into this and so trying to make a vaccine specific for a cell while polysaccharide immunogen From these clostridia and to see if we can actually, you know get rid of them So but I have to say, you know Given everything that's been talked about, you know about I think which is great about the ecosystem of the microbiota You know, what could be the consequences of actually, you know playing god and targeting these microbiota with vaccines So this is sort of virtually unexplored, but if you're targeting specific Constituents of the microbiota, you know, what are the ripple down effects in the community? And this is very difficult to predict and I think David Relman has done some great work in this area looking at The importance and interactions and ecosystem dynamics of the microbiota across the planes and how they actually turn dysbiotic or not So we need to know it's still there's still a need for this basic science I know the contribution of each species to the community because we got to remember this microbial ecosystems a complex adaptive system Is non-linear so very small changes can have profound effects in the community And I think this is well known for microbial ecologists in the field So I just like to leave you with some future challenges and questions For the field. So one is, you know, can the microbiota be altered to improve vaccine responses Can you actually use microbiota to deliver vaccine antigens? And possibly can specific vaccines be designed to target particular trouble maker microbiota strains? And with that, I just like to acknowledge Brett and the lab and And thank for a great conference. Thanks so now We'll invite for the Open floor all those keynote speakers here And we will be around for taking questions and those questions will be from this session or other sessions as well Thank you Before we get started on the open floor discussion, you recall we had a poster competition. It turns out two