This application is for a renewal of my K24 Midcareer Investigator Award in Patient-Oriented Research (POR) on Chlamydia trachomatis (CT) Infections. I, Dr. William Geisler, am a federally-funded physician scientist at the University of Alabama at Birmingham (UAB) with expertise in CT infections and significant mentoring experience. During the initial K24 period, I obtained new funding (R01 renewal, a new R01, a new R21, etc.), expanded my POR program in new directions, had 35 publications, became UAB Assistant Dean for Physician Scientist Development, and mentored 16 early stage investigators who had many successes (awards included a K08, KL2, TL1, an F30, an F31-D, etc.). The protected time afforded by this K24 renewal would enable me to: 1) broaden my mentoring knowledge and develop new research skills, 2) continue providing POR mentoring to early stage investigators, and 3) expand my research program in new directions. Despite current CT prevention and control efforts, CT infection rates continue to rise and CT remains the most prevalent bacterial STI worldwide, one with significant disparities in women and African Americans and associated with reproductive morbidity. A CT vaccine is urgently needed. However, a better understanding of immunogenetic determinants that impact CT infection risk and which CT antigens are most immunogenic and induce protective immunity to CT is needed to advance vaccine development; My Current POR is focused on this need (2R01AI093692 and 1R01AI148359). CT vaccine availability does not ensure it will be utilized. Lessons learned from HPV vaccine implementation have taught us that psychosocial and behavioral factors influence STI vaccine acceptability and studies on factors impacting CT vaccine acceptability are needed. In this K24 renewal, I plan to broaden my mentoring knowledge through didactic and interactive experiences, develop new research skills in entrepreneurship and research commercialization through didactic and experiential training under mentorship, and continue mentoring early stage investigators in POR. Mentees will be provided with educational and research experiences tailored to their career stage and interests. Mentoring will be on my Current CT immunogenetics POR (noted above and discussed in detail in this application) and on two new POR studies suported by this K24 renewal award that will expand my CT POR program. New Study 1 aims to determine if HLA-DQB1*06 and CT-specific CD4+ IFN-g can be useful biomarkers for predicting incident CT infection; I previously found that DQB1*06 was a risk marker and CD4+ IFN-g a protective marker for CT reinfection. Findings can be used to guide CT testing frequency in women based on incident CT infection risk determined by the biomarkers. New Study 2 seeks to identify enabling and limiting factors that affect acceptability of a CT vaccine through surveys and qualitative interviews to aid in designing strategies to increase CT vaccine uptake. The long-term goa...