Entry mechanisms of mycobacteria
Related Experiment Video
Updated: Oct 7, 2026
Preparation of Mycobacterium tuberculosis Culture Filtrate to Understand TB Pathogenesis
Published on: March 28, 2025
1Dept. of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, 203 VBS, Fair and East Campus Loop, Lincoln, NE 68583, USA.
Abstract:
Since many mycobacteria are facultative intracellular pathogens, their ability to cause disease involves entry, survival and replication within host cells. Despite the fact that mycobacteria were first associated with disease more than 125 years ago, the first step in the production of an infection, entry into host cells, is not well understood. Mycobacteria have the ability to enter a number of different cell types, but the primary cell type that they are thought to replicate within during human disease is macrophages. Since macrophages have a large number of receptors that are designed for relatively non-specific uptake of foreign particles, there are multiple routes by which nearly any bacteria can be taken up. The outcome of mycobacterial entry into macrophages via different mechanisms is unclear. Although it is thought that mycobacteria may enter macrophages by a mechanism that allows them to avoid lysosomal fusion, it remains possible that mycobacteria enter by more than one mechanism, yet remain viable and replicate intracellularly through modification of the phagosome. In the current discussion we will review mycobacterial research specifically relating to the mechanisms of entry into host cells. Although much progress has been made in our understanding of entry by mycobacteria, we anticipate that clarification of the role of entry in pathogenesis will require further application of newly developed molecular tools to dissect each of the proposed mechanisms.
Insights
Mycobacteria cause disease by entering host cells, but the exact entry mechanisms remain unclear. Further research using molecular tools is needed to understand how mycobacteria infect macrophages and cause disease.
Area of Science:
- Microbiology
- Immunology
- Pathogenesis
Background:
- Mycobacteria are facultative intracellular pathogens causing disease through host cell entry, survival, and replication.
- Despite over 125 years of study, the initial step of infection, host cell entry by mycobacteria, is poorly understood.
- Macrophages are the primary host cells for mycobacterial replication during human disease.
Purpose of the Study:
- To review current research on mycobacterial mechanisms of entry into host cells.
- To highlight the lack of understanding regarding the consequences of mycobacterial entry via different pathways into macrophages.
- To emphasize the need for further investigation into mycobacterial entry mechanisms and their role in pathogenesis.
Main Methods:
- Review of existing mycobacterial research focusing on host cell entry mechanisms.
- Discussion of potential entry routes into macrophages, considering their non-specific particle uptake receptors.
- Exploration of hypotheses regarding mycobacterial survival and replication post-entry, including lysosomal fusion avoidance and phagosome modification.
Main Results:
- Mycobacteria can enter various host cell types, with macrophages being a key target for replication.
- Multiple entry routes into macrophages exist due to their non-specific uptake mechanisms.
- The precise outcome of mycobacterial entry via different mechanisms and their intracellular survival strategies are not fully elucidated.
Conclusions:
- Understanding mycobacterial entry into host cells is critical for comprehending pathogenesis.
- Further research employing advanced molecular tools is essential to dissect the proposed entry mechanisms.
- Clarifying the role of entry mechanisms in mycobacterial pathogenesis will advance disease control strategies.
More Related Videos
Related Concept Videos
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:23Tuberculosis
01:25Mechanism of Antibiotic Resistance in MRSA
01:20Determinants of Bacterial Pathogenicity and Virulence
01:25Colonisation of Pathogens
01:20Receptor-mediated Endocytosis
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...