Human M. tuberculosis infection/ disease: classical pathology and immunology (Slide -1) W. Henry Boom, M.D. Tuberculosis Research Unit (TBRU) Case Western Reserve University W. Henry Boom, M.D. Tuberculosis Research Unit (TBRU) Case Western Reserve University NIAID-DMID: -AI70022 Cattle Prod 1950

Route(s) of Infection & Natural Course (Slide 0) small vs. large droplet aerosol repeated exposure ?infectious dose (animals: 1-10 CFU) ?repeated infection small vs. large droplet aerosol repeated exposure ?infectious dose (animals: 1-10 CFU) ?repeated infection Bacterial Load I O PROGRESSIVE: PEDS.+IMMUNOCOMP. (5%) I O PROGRESSIVE: PEDS.+IMMUNOCOMP. (5%) REACTIVATION/ADULTS (5-10%) REACTIVATION/ADULTS (5-10%) INFECTION (90+%) INFECTION (90+%) Time (mos-yrs)

Pulmonary Tuberculosis (slide 1) Cough (+/-RBC), Wt. Loss, Night sweats CFU Diagnosis: Sputum Smear/Culture (<50% paucibacillary) Pathology: Caseating Granulomas, Necrosis, Cavitation (?Host or Microbe) Death: –Cachexia –Respiratory Failure –Dissemination (miliary, meningitis) –Massive Hemoptysis Cough (+/-RBC), Wt. Loss, Night sweats CFU Diagnosis: Sputum Smear/Culture (<50% paucibacillary) Pathology: Caseating Granulomas, Necrosis, Cavitation (?Host or Microbe) Death: –Cachexia –Respiratory Failure –Dissemination (miliary, meningitis) –Massive Hemoptysis

Immunology of M. tuberculosis infection and disease (slide 2) Bacterial Load REACTIVATION INFECTION InnateAdaptive Failure (Immunopathogenesis?) TLR’s Chemokines Cytokines Antigens T cell subsets Effector mech. Immune evasion TLR’s Chemokines Cytokines Antigens T cell subsets Effector mech. Immune evasion

“Known knowns, known unknowns, unknown unknowns” and dogma for immunology of human TB (slide 3, “adapted from Donald Rumsfeld ‘03”) Known: –Adaptive immunity –CD4+ T cell –TNF-alpha –IFN-gamma –IL-12 Unknown: –Genetics: which ones/stage (IFNgamma/IL12 pathway, NRAMP1, TNFalphaR, etc.) –TLRs: which ones/when –Chemokines: same (MCP1)? –What does IFN-gamma do? –Immunology of the lung: why so slow? –Antigens matter: which ones, when, where? Known: –Adaptive immunity –CD4+ T cell –TNF-alpha –IFN-gamma –IL-12 Unknown: –Genetics: which ones/stage (IFNgamma/IL12 pathway, NRAMP1, TNFalphaR, etc.) –TLRs: which ones/when –Chemokines: same (MCP1)? –What does IFN-gamma do? –Immunology of the lung: why so slow? –Antigens matter: which ones, when, where? Dogma: –“Immuno-pathogenesis” (HIV: cavitation related to CD4, but mortality still high) –CD8’s critical, cause of BCG failure –It is all about cytokines (cytokine interventions have failed) –Now it’s Tregs, Th17……… Unknown unknowns: –TLRs in last century –Why all T cell vaccines have failed so far (TB, HIV)? T MM TNF- , IL-12 IFN- 

Panel III: Immune Relevancy Sacred “cows”, questions and other musings

Questions to consider….. Can host responses/markers tell us when infection progresses to disease? –Or is it detecting something from MTB that tells us CFUs are increasing? Is Th1 vs. Th2 paradigm (still) useful? –Ineffectual/failed Th1 rather than Th2? Balance of cytokines or do antigens matter? –For vaccines likely? For progression maybe not? For relapse/reinfection don’t know? Evidence that host responses are responsible for pathology? –Aren’t granulomas in the right places good? Does it depend on the stage of infection? Can we intervene to prove it? What’s up with the lungs? –Why the sluggish response? What is unique about the lungs as immune environment/sanctuary for MTB? Can host responses/markers tell us when infection progresses to disease? –Or is it detecting something from MTB that tells us CFUs are increasing? Is Th1 vs. Th2 paradigm (still) useful? –Ineffectual/failed Th1 rather than Th2? Balance of cytokines or do antigens matter? –For vaccines likely? For progression maybe not? For relapse/reinfection don’t know? Evidence that host responses are responsible for pathology? –Aren’t granulomas in the right places good? Does it depend on the stage of infection? Can we intervene to prove it? What’s up with the lungs? –Why the sluggish response? What is unique about the lungs as immune environment/sanctuary for MTB?

How can natural/experimental infection in animals help with these questions? Natural history of infection and progression to disease (many) –Transition between stages/markers of transition Pathology-granuloma, caseation, cavitation (rabbit, guinea pig) –MTB mutants/host genetic variants that differ in induction of pathology with similar CFU Role of innate vs. adaptive immunity (mouse, primate, bovine) –Models difficult to infect, innate KO’s Genetics of different stages (mouse, bovine, fish, ?others) –Infection, progression, reactivation vs. relapse Drug Treatment (mouse, rabbit, primate, fish) –Latent vs. active infection (penetration/efficacy, PK, ARV) Vaccine (mouse, guinea pig, primate, bovine) –Infection, dissemination vs. re-activation Co-pathogenesis-HIV or helminth co-infection (primate) –Maybe asking too much……. Natural history of infection and progression to disease (many) –Transition between stages/markers of transition Pathology-granuloma, caseation, cavitation (rabbit, guinea pig) –MTB mutants/host genetic variants that differ in induction of pathology with similar CFU Role of innate vs. adaptive immunity (mouse, primate, bovine) –Models difficult to infect, innate KO’s Genetics of different stages (mouse, bovine, fish, ?others) –Infection, progression, reactivation vs. relapse Drug Treatment (mouse, rabbit, primate, fish) –Latent vs. active infection (penetration/efficacy, PK, ARV) Vaccine (mouse, guinea pig, primate, bovine) –Infection, dissemination vs. re-activation Co-pathogenesis-HIV or helminth co-infection (primate) –Maybe asking too much…….