Th1 to Th2: Can worms, bacteria or allergens cause the switch?

1. Th1 to Th2: Can worms, bacteria or allergens cause the switch? Anna, Vinay, Soo-Kwan, and Megan April 7, 2003 BE.214

2. Hypothesis • Th1 and Th2 responses are mutually antagonistic. • Therefore, switching the response from Th1 to Th2 in the gut in Crohn’s disease can ameliorate the disease. • AIM: • Induce a Th2 response • localized to the gut or able to have an effect on gut • strong enough to tip the balance (from Th1 in gut) • in an acceptable manner • STEPS. • Identification and design of right • Immunogenic component • Delivery method • Characterization of immune response • cytokines • cell interactions • innate and adaptive interactions

3. Preliminary Evidence Experimental evidence suggesting Th1 to Th2 switch has beneficial effect on Crohn’s disease Steidler– IL10 secreting lactobacilli Weinstock – studies with worms in humans Studies with worms in animal models.

4. localised to the gut • Th1 to Th2 switch needed at the gut. • -- i.m. or s.c immunisation may not induce response in the gut. • Oral route required. BUT Oral route of antigen delivery typically induces tolerance. -- no immune response to Food ! Why? Absence of co-stimulation. Oral antigens need an adjuvant for immune response. NOTE: All oral vaccines (e.g. Polio, typhoid (Typhoral), rotavirus vaccine) are live attenuated organisms.

5. Localized to gut Th1 to Th2 switch needed at the gut. -- i.m. or s.c immunisation may not induce response in the gut. Oral route required. BUT Oral route of antigen delivery typically induces tolerance. -- no immune response to Food ! Why? Absence of co-stimulation. Oral antigens need an adjuvant for immune response. NOTE: All oral vaccines (e.g. Polio, typhoid (Typhoral), rotavirus vaccine) are live attenuated organisms. Or have effect on gut Localized to gut or have an effect on gut Elliot et al. showed intraperitoneal Injection of S. Mansoti freeeze-killed Eggs may limit the effects of TNBS induced colitis in mice by forcing a Th1 to Th2 switch in the gut at the time of TNBS treatment

6. 2. strong enough to tip the balance • How? • Parasitic infection – • Strongly induce infiltration of eosinophils and Th2 cells. • Eosinophils produce large amounts of Th2 cytokines (IL4). • b) Exploit a memory response. • Immunize with an Th2 antigen - s.c./ i.m. • And Give the antigen orally during disease exacerbation • c) Adjuvants 3. in an acceptable manner • Worm components • Food Allergens • No human pathogens, no brain parasites!

7. Choice of worm • Criteria • non-humanparasite (cannot infect humans) • can beculturedin vitro • if possible incell freemedium • Or easily harvested from native host • Heligosomoides polygyrus • - An adjuvant to prime for an Ag-specific Th2 response • : IL-4, IL-10 • - Protection against an Allergic response • : Down-regulation of PN Ag-specific IgE response • Trichinella spiralis • - Prior exposure cause reduction of the severity of DNBS • mediated colitis • : Increase of IL-4, IL-13 and decrease of IL-12, IFN • Acanthocheilonema viteae • - ES-62 (PC-containing glycoprotein) induce the maturation • of DC2 with the capacity to induce Th2 response • : Increased IL-4 and decreased IFN ) • - ES-62 induces a Th2 response in vivo : Increased IgG1/IgG2a Not easy to culture through entire length of life cycle

8. Choice of allergen • Criteria • Universal • Mild • Availablity of antidote (Ab ?) • Possibilities: Ragweed, seafood, peanut, dust mite Problems: Food allergens not well characterised as compared to respiratory allergens Idiosyncratic response to allergens. Allergic colitis is quite rare--> it may be hard to get a gut localized Th2 response from food allergens (?)

9. Worm Extracts! Killed Worms? or Worm components? Benefits Killed “whole” organisms are better immunogens than those made of single components Some “Pathogen associated molecular patterns” retained in killed organism Drawbacks Both are worse than live organism Among two, component antigens may need stronger adjuvants PROBLEM: Body may treat both like exotic oriental food and do nothing apart from digesting them. Although this may not provide a miracle treatment, it may allow for a characterization of the immune response associated with parasite induced Th1-->Th2 switch ADVANTAGE: Anna can (WILL) capture the ‘natural product’ market!

10. Like Silk Worm, all are insect larvae For mammals, nematodes are invariably parasites (?) http://www.petros.com.my/eatworms.htm http://www.mckandy.com/page/309 http://www.ent.iastate.edu/misc/insectsasfood.html Know someone who eats worms or worm extracts for a snack? Has he ever got Crohn’s disease? TRY GOOGLE FOR THESE RECIPES ! Meal Worm Army WormRoot Worm Sago Worm

11. PLAN Arrive at best formulation. screen + Advjuvant OR one of the components itself acts as an adjuvant Use mouse serum to purify immunodominant Ag in extract

12. TNBS enema C3H/HeJBir C. rodentium Acute Inflammation Chronic Inflammation In vivo Models Naturally occuring, sponateous colitis Th1 disease Bacterial cause Th1 mediated colitis

13. Delivery Possibilities multi-component bio-engineered “immune response switching beads” Extract equivalent to Food if given orally Protective coat that Keeps bead intact until it Reaches the inflamed zone IL-10 Surface studded with choicest Ragweed, worm and fungus Components. IL10, IL4 slow release

14. Delivery Possibilities Commensal Vectors • Make Super-Bugs that produce– • IL10 • Parasite Ag (wormified bacteria) • Allergens • Ab to IFNg or other Th-1 cytokines • Eosinophil Chemotactic Agents • ON DEMAND – regulated promoters • Focus on bacteria that are non-pathogenic possibly consider chronic treatment with non-colonizing bacteria • Specifc commensal bacteria for drug targeting to different • zones of intestine (different zones have different microflora)

15. Use of Live Worms • Engineered strains with desirable properties • Increased susceptibility to antihelminthic • Low replication rate • Note: Genetic engineering of worms difficult if they • cannot be cultured in vitro. • Expose eggs to Irradiation? Mutagens? • Non-engineered worms that remain in the gut and cause no/limited systemic effects that can be eventually cleared (?) • Guarantee of strong Th2 response each time administered