THE HUMAN IMMUNE SYSTEM
TYPES OF IMMUNITY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Engulfing a pathogen inside a phagosome
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Digesting the pathogen using antibodies
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Attraction of phagocytes to pathogens by chemicals
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Phagosome fuses with lysosomes
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Each phagocyte will only destroy a specific pathogen
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Detailed explanation-1: -Macrophages internalize pathogens through phagocytosis, entrapping them into organelles called phagosomes. Phagosomes then fuse with lysosomes to mature into phagolysosomes, acquiring an acidic and hydrolytic lumen that kills the pathogens.
Detailed explanation-2: -In the final step, the phagosome fuses with the cell’s lysosomes, forming a phagolysosome which functions to finally destroy the pathogen. Acidification of phagosomes is an important part of phagocytosis.
Detailed explanation-3: -Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation.
Detailed explanation-4: -The fusion of the phagosome with lysosomes forms the mature phagolysosome (PL) which has full degradative and microbicidal capacity. Heterotypic fusion between the phagosome and lysosome is imperative for phagocytes to carry out their functions in immunity and homeostasis and is a tightly regulated process.
Detailed explanation-5: -Phagosomes Fuse with Late Endosomes and/or Lysosomes by Extension of Membrane Protrusions along Microtubules: Role of Rab7 and RILP.