During the primary immune response, IgM is typically the first antibody produced, followed by IgG.
The primary immune response is the body's initial reaction to a previously unencountered antigen. This process involves several key events and the production of various immune components. Here's a breakdown:
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Antigen Recognition: Naive B cells and T cells recognize the foreign antigen.
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Activation and Proliferation: These cells get activated, proliferate (clonal expansion), and differentiate.
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Antibody Production:
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IgM: Immunoglobulin M (IgM) is the first antibody isotype produced in significant quantities. IgM is effective at activating the complement system, which helps to eliminate the antigen.
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IgG: Immunoglobulin G (IgG) production follows that of IgM. IgG is considered a major protective antibody, and memory B cells exclusively release it upon subsequent encounters with the same antigen.
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Cell-Mediated Immunity:
- Cytotoxic T lymphocytes (CTLs): These cells are generated to directly kill infected cells.
- Helper T cells (Th cells): Different subsets of Th cells (e.g., Th1, Th2) are generated, producing cytokines that help coordinate the immune response.
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Memory Cell Generation: A subset of activated B and T cells differentiate into memory cells, which provide long-lasting immunity. These memory cells are quiescent but can quickly respond upon re-exposure to the same antigen.
In summary, the primary immune response results in the production of IgM and then IgG antibodies, cytotoxic T lymphocytes (CTLs), helper T cells (Th cells), and memory cells. These components work together to eliminate the antigen and provide future protection.
