Question

How do the following bacteria evade the immune system?

(1) Stahylococcus aureus

(2) Listeria monocytogenes

(3) Neisseria meningitidis

Answer 1

1. Staphylococcus aureus

Staphylococcus aureus secrete proteases that disrupt the structure of extracellular matrix and their intercellular connections, leads to disturbances in stability of host.

By another way S. aureus secretes proteins that can activate host zymogens which that targe defense components of host.

These Secreted protein also inhibit the anti-bacterial function of blood neutrophils & complement system, this benefits to survivalance of S. aureus.

2. Listeria monocytogene

Pathogenic gram positive bacteria, generally cause food borne diseases.

L. monocytogenes cause evade immune system by continues exposure to host cell when it is well adapted to this environment it produces multiple factors to compete with microbiota and counteract antimicrobial peptides, acidity, bile and iron deprivation etc.

L. monocytogenes has its capacity to invade enterocytes, hepatocytes and trophoblast cells. This phagocytic cell invade by pathogen's virulence capacity.

3. Neisseria meningitidis

N. meningitidis evade immune systems by mimicry of host molecules such as capsule and lipopolysaccharide, etc. This make to produce vaccines difficult. N. meningitidis uses multiple mechanisms to avoid host immune systems such as antimicrobial proteins, phagocytes & the complement system.