Question

Each of the following will enhance and promote phagocytosis, except Multiple Choice tumor necrosis factor (TNF) and other cytokines. deposition of complement fragments on bacterial cells. interaction of TLRs and PAMPs. deposition of interferon on bacterial cells.

Answer 1

Answer:

The correct answer is: deposition of interferon on bacterial cells.

Explanation:

Phagocytosis is the mechanism by which a cell uses its plasma membrane to ingest a big particle, forming a phagosome within the cell. It's a form of endocytosis used by the immune system to eliminate pathogens such as bacteria and cell debris.

Phagocytosis can be enhanced through various ways when an infection is taking place in the body. For example, cytokines and TNF are secreted by different kinds of cells to stimulate this process - for these cytokines to be released, certain parts of the bacteria called PAMPs need to be recognized by specific receptors located in phagocytes and epithelial cells called TLRs. Another way to stimulate this mechanism is by depositing complement fragments on bacterial cells, which is done thanks to the Complement cascade, a system of great importance in the innate immune response against extracellular bacteria - these fragments will opsonize ("mark") the pathogens for the phagocytes to recognize them and engulf them.

Interferon, on the other hand, while hugely important on the immune response against viruses and other pathogens that infect our cells by entering them and using their organelles to replicate and translate proteins, is not an enhancer of phagocytosis, as it is mostly involved in the translation of genes that will lead to the infected cell's death.