Project Grant F31AI202779

DEFINING SYNERGISTIC MULTI-ADJUVANT MECHANISMS THAT PROMOTE TH1 IMMUNITY AND PROTECTION AGAINST CHLAMYDIA - PROJECT SUMMARY CHLAMYDIA TRACHOMATIS (CT) IS THE MOST PREVALENT BACTERIAL SEXUALLY TRANSMITTED INFECTION WORLDWIDE, CAUSING OVER 100 MILLION INFECTIONS ANNUALLY. CT DISPROPORTIONATELY AFFECTS WOMEN, OFTEN PROGRESSING ASYMPTOMATICALLY TO THE UPPER GENITAL TRACT AND RESULTING IN OVIDUCT SCARRING, INFERTILITY, ECTOPIC PREGNANCY, AND CHRONIC PELVIC PAIN. CLEARANCE OF CT REQUIRES IFNG CD4 T CELL (TH1) RESPONSES, WHICH ARE NOT RELIABLY ELICITED BY CURRENT VACCINE ADJUVANTS, HIGHLIGHTING THE URGENT NEED FOR RATIONALLY DESIGNED VACCINES THAT INDUCE POTENT, DURABLE TH1 IMMUNITY. THE LONG-TERM GOAL OF THIS PROJECT IS TO DEVELOP A SAFE AND EFFECTIVE CT VACCINE. THIS PROPOSAL FOCUSES ON THE OPTIMIZATION OF A SUBUNIT VACCINE COMPRISING THE CONSERVED IMMUNODOMINANT CHLAMYDIAL PROTEASE-LIKE ACTIVITY FACTOR (CPAF) CONJUGATED TO THE STING AGONIST CL1151. IN MICE, CPAF-CL1151 ELICITS STRONG TH1 RESPONSES AND REDUCES BACTERIAL BURDEN BUT DOES NOT FULLY PREVENT OVIDUCT PATHOLOGY. TO ENHANCE THE EFFICACY OF CPAF-CL1151, WE WILL EVALUATE THE SAFE, FDA-APPROVED ADJUVANTS CPG (TLR9 AGONIST) AND QS-21 (SAPONIN), EITHER ALONE OR TOGETHER, IN BOTH ADMIXED AND LIPID NANOPARTICLE (LNP)-ENCAPSULATED FORMULATIONS TO TEST THE HYPOTHESIS THAT ADDITIONAL ADJUVANTS AND LNP ENCAPSULATION WILL IMPROVE LYMPH NODE TARGETING, ANTIGEN-PRESENTING CELL UPTAKE, AND TH1-BIASED ADAPTIVE IMMUNITY. AIM 1 WILL DEFINE THE MINIMAL COMBINATION OF ADJUVANTS AND ADMINISTRATION ROUTES REQUIRED FOR OPTIMAL PROTECTION AGAINST GENITAL CHLAMYDIA. AN ESTABLISHED FEMALE C57BL/6 MOUSE MODEL OF GENITAL CHLAMYDIA MURIDARUM INFECTION WILL BE USED TO COMPARE TH1 INDUCTION AND PROTECTIVE IMMUNITY ELICITED BY INTRAMUSCULAR (I.M.) VACCINATION VERSUS COMBINED I.M./INTRANASAL DELIVERY OF THE MOST IMMUNOGENIC AND SAFE VACCINE FORMULATIONS. AIM 2 WILL ELUCIDATE THE MOLECULAR AND CELLULAR PATHWAYS DRIVING VACCINE-ELICITED TH1 IMMUNITY. THE ROLES OF SUBCAPSULAR SINUS MACROPHAGES, NK CELLS, AND BATF3 DENDRITIC CELLS WILL BE DETERMINED USING TARGETED DEPLETION AND KNOCKOUT MOUSE MODELS, WITH TH1 RESPONSES MEASURED BY ELISPOT AND INTRACELLULAR CYTOKINE STAINING. ANTIGEN UPTAKE, INNATE IMMUNE CELL RECRUITMENT, AND TRANSCRIPTIONAL RESPONSES WILL BE PROFILED IN DRAINING LYMPH NODES USING FLUORESCENTLY LABELED CPAF-CL1151 AND CITE-SEQ. THIS PROJECT WILL BE CARRIED OUT AT THE UNIVERSITY OF NORTH CAROLINA - CHAPEL HILL WHICH PROVIDES EXTENSIVE RESOURCES FOR RIGOROUS TRAINING IN FLOW CYTOMETRY, IN VIVO MOUSE MODELS, IN VITRO MECHANISTIC ASSAYS, AND COMPUTATIONAL IMMUNE ANALYSIS. MENTORSHIP, STRUCTURED CAREER DEVELOPMENT, AND SCIENTIFIC COMMUNICATION TRAINING WILL SUPPORT PROGRESSION TO A POSTDOCTORAL POSITION AT THE INTERFACE OF VACCINE DESIGN, MUCOSAL IMMUNOLOGY, AND INFECTIOUS DISEASE. SUCCESSFUL COMPLETION WILL DEFINE OPTIMAL ADJUVANT COMBINATIONS AND DELIVERY STRATEGIES TO DRIVE DURABLE TH1 IMMUNITY AGAINST CT AND PROVIDE INSIGHTS TO GUIDE NEXT-GENERATION VACCINES FOR INTRACELLULAR PATHOGENS.