Targeted vaccines against pulmonary NTM infections in vulnerable populations - NTM infections have now surpassed tuberculosis in the U.S. and are a global concern. Long (>12 months) treatment regimens and severe toxic side effects of drug treatment warrant urgent development of new strategies. We hypothesize that a vaccine targeted against pathogenic NTM will improve immunity in at- risk individuals, prevent NTM-lung disease (NTM-LD), and improve therapeutic clinical outcomes when used as an adjunct to drug treatment. We propose the development of two innovative NTM-LD vaccine candidates: an adjuvated subunit vaccine and a novel replicon RNA-based vaccine. The 13 vaccine candidate antigens, which have known importance in Mycobacterium avium (MAV) and Mycobacteroides abscessus (MAB) infections, will undergo a thorough search for homology to >1,700 clinical NTM isolates. The 3 adjuvants that will be tested are similar to those that have undergone human clinical vetting, including AS01E, GLA-SE, and CAF01. Subunit vaccine candidates will be screened using an innovative NTM mycobacterial growth inhibition assay (N- MGIA). The top 4 antigen candidates that provide the greatest reduction in bacteria in the N-MGIA will be included as a ‘combo’ and mixedwith the 3 clinically relevant adjuvants. RNA-based replicon vaccines, designed to express the 4 antigens, will be combined similar to the subunit vaccine, for further in vivo efficacy studies. We have a scientifically rigorous plan to evaluate efficacy of the NTM vaccine candidates in mouse models incorporating (i) parenteral and mucosal routes of immunization, (ii) vaccine durability (6 months), (iii) efficacy evaluation using two different clinical NTM isolates (MAV and MAB), (iv) use of BCG as a control vaccine, and (iv) C57BL/6, Beige, and C3HeB/FeJ (Kramnik) mouse models for vaccine efficacy testing (reduction in bacteria and lung pathology). Rigor of prior research is included in 2 published papers showing efficacy with BCG and a prototype subunit vaccine against a clinical isolate of MAV. In this work, the aerosol route of infection leads to lung disease in Beige mice. We are also utilizing the published MAB model in C3HeB/FeJ mice, where infection with a clinical MAB isolate is achieved through intravenous (i.v.) injection. Both male and female mice will be included to determine whether ‘sex as a biological variable’ mimics that seen in women, where incidence and prevalence of NTM-LD is greater than that observed in men. Animal numbers for our experiments are powered for efficacy based on prior statistical power calculations and past NTM challenge experiments. Our vaccine candidates will be evaluated in high-risk target population mouse models, including (i) use of anti-TNF strategies, (ii) aged populations, and (iii) chronic obstructive pulmonary disease (COPD). Vaccine efficacy will also be tested as an adjunct to drug treatment (Amikacin) in a MAV therapy model. This work, through an extension of our prior R21 and based on a systematic approach towards vaccine development, will allow delivery of an NTM-LD vaccine. We have previously developed M72/AS01E and ID93+GLA-SE, both in Phase 2 clinical trials. Funding this R01 project to develop an NTM-LD vaccine will address this global infectious disease threat.
