Abstract

Nontuberculous mycobacteria (NTM) are the mycobacterial species other than Mycobacterium tuberculosis, which causes tuberculosis, and Mycobacterium leprae, which causes leprosy. Diseases caused by NTM are on the rise in the United States and are steadily becoming a significant public health problem globally, particularly in developed countries. Despite the ability of NTM pathogens to interact with the host immune system, the proteins responsible for eliciting host immune responses remain unidentified, making the accurate and timely diagnosis of the disease a challenge. In this study, we tested the hypothesis that NTM strains secrete proteins that stimulate immune responses. Our study showed that the culture filtrate proteins (CFP) prepared from Mycobacterium abscessus, M. intracellulare subsp. chimaera, and M. intracellulare stimulated human peripheral blood mononuclear cells (PBMC) from healthy adults to produce IFN-γ. Similarly, the CFP induced IL-6, TNF-α, and IL-10 production by monocyte-derived macrophages (MDMs) and monocyte-derived dendritic cells (MDDCs) without the involvement of lipopolysaccharide. Superdex 75 size-exclusion chromatography and immune cell stimulation screening of the five major protein fractions of the CFP from Mycobacterium intracellulare identified the fractions with a molecular weight of 45 - 60 kDa as the major immune cell stimulator. We conclude that specific proteins of NTM CFP stimulate human immune cells and identification of these proteins will guide us to design novel diagnostic and preventive measures with improved clinical management of NTM diseases.

Date of publication

Spring 5-14-2026

Document Type

Thesis

Language

english

Persistent identifier

http://hdl.handle.net/10950/5068

Degree

Master of Science in Biotechnology

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