Question

Antigen processing would involve which of the following for antigen -presenting cells?

The immune cells take peptides 8 - 10 amino acids long directly from which organelle in the cytosol?

How does the immune system recognize that a cell is infected with a virus?

Answer 1

1. Answer:

Antigen processing occurs by the immune cells that engulf and process antigens and expose them to their surface to T- cells. These displayed foreign antigens complexed with MHCs (Major Histocompatability complexes) on their surfaces and recognized by the TCR (T – cell receptor). T cells responds to the complexed antigens or processed antigens by APC (antigen presenting cells) but not free antigens.

2. Answer:

The immune cells like MHC- I molecules are made by all nucleated cells in the body and had a deep grove which can bind to the peptides 8 – 10 amino acids from endogenous antigens. These MHC-I / Peptide which involves action with cytotoxic T & T8 lymphocytes which possess a complementary T – cell. These recognize infected cells and tumor cells and kill them with cytotoxic T lymphocytes or CTLs.

3. Answer: The immune system recognizes the viruses in early stages through rapid onset innate response against the virus and involves in the protein synthesis known as interferons which stimulates natural killer lymphocytes. If the infection proceeds, the adaptive immune response destroys very rapidly through humoral response (synthesis of virus specific antibodies by B - lymphocytes) and through cell mediated response (the synthesis of specific cytotoxic T lymphocytes that kill infected cells) and very effective against virus.

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