Using your pathogen chosen in the Week 1 discussion, describe its cellular characteristics. Describe which of these structures are used to help it attach/invade/survive in the host.
Pathogen: Mycobacterium tuberculosis (MTB) is an acid-fast bacillus-shaped bacterium that infects lung alveoli and is the causative agent of tuberculosis – a disease that is currently known as a global challenge. Tuberculosis may remain latent in approximately 90% of the individuals, and active disease is considered to be a failure of CD4 T-cell-mediated immunity (Korb et al., 2016). MTB infection is established via inhalation of infected droplets from sick individuals and results in symptoms like bloody cough and apnea. MTB is recognized by pattern recognition receptors (PPR) located in macrophages and dendritic cells (DC) – which results in MTB engulfment. Although modified phagosomes within macrophages are classical reservoirs for MTB replication, macrophages, are also the main cell responsible for MTB clearance (Korb et al., 2016). Infected macrophages elicit a strong initial response against MTB via TLR-2 signaling. Chronic TLR-2 signaling, however, may impair proper immunity, and may even hide MTB from T-cell recognition – thus, contributing to this pathogen’s known latency status (Korb et al., 2016). Additionally, alveolar macrophages enter the lung interstitium after MTB engulfment, which results in the establishment of the site of infection. MTB may also prevent apoptosis within macrophage’s phagosomes, which also contributes to MTB’s latency (Korb et al., 2016).
References:
Korb, V. C., Chuturgoon, A. A., & Moodley, D. (2016). Mycobacterium tuberculosis: Manipulator of Protective Immunity. International journal of molecular sciences, 17(3), 131. https://doi.org/10.3390/ijms17030131 (Links to an external site.)
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