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Humoral immunity :
Immunology is the study of the molecular and cellular components that make up the immune system, as well as their function and interaction. Invertebrates have two immune systems: an innate immune system and an acquired or adaptive immune system, both of which contain humoral and cellular immunological elements
Humoral immunity refers to the part of immunity mediated by macromolecules found in extracellular fluids, such as released antibodies, complement proteins, and some antimicrobial peptides. Humoral immunity gets its name from the fact that it incorporates humours, or bodily fluids. It’s the polar opposite of cell-mediated immunity. Antibody-mediated immunity is another term for humoral immunity.
What is the process of making antibodies?
Each B cell produces antibodies with antigen-specific binding sites that are distinct from those produced by other B cells. To recognise potential infections, toxins, and external material, naive B cells produce antibodies that adhere to the cellular surface. Immunoglobulin is the term used to refer to an antibody that is surface-bound.
When an antigen that attaches to the antigen-binding site binds to a naive or memory B cell, the B cell is activated, and it produces and secretes additional antigen-specific antibodies. A plasma cell is a B cell that has fully matured and will continue to generate and release antigen-specific antibodies throughout the rest of its life cycle.
What role do antibodies play in the battle against pathogens?
Antibodies are free-floating proteins that can operate as defence molecules with both direct and indirect immunological effects once they reach the bloodstream. These are some of the functions:
inhibiting or antibody-dependent cellular cytotoxicity to neutralise pathogenic pathogens.
Activation of the complement system – cytotoxicity that is dependent on the complement system opsonization and phagocytosis are the binding of foreign substances to be eliminated.
Cell mediated immunity:
In response to a non-self-antigen, cell mediated immunity (CMI) includes the activation of macrophages and natural killer cells (NK cells) to enable them to destroy intracellular pathogens, the generation of antigen-specific CD8 cytotoxic T lymphocytes (CTLs), as well as the release of cytokines that regulate the activity of other cells engaged in both adaptive and innate immune responses
Cell-mediated immunity is primarily responsible for the removal of virus-infected cells, but it also plays a role in the defence against fungi, protozoa, intracellular bacteria, and cancers.
It also plays a significant role in transplant rejection.
Lymphocytes that play a role in cell-mediated immunity include the following:
Nave T cells, helper T cells, killer T cells, and macrophages are the most common lymphocytes involved in cell-mediated immunity. The bloodstream and lymphatic system contain naive T cells, which have not yet become activated. These naive cells become activated when they come into contact with an antigen-presenting cell,quickly multiplying into several T-cell subsets. CD4+ helper T cells, for example, release a series of signalling proteins known as cytokines. These cytokines can either directly harm the target cell or aid in the activation of “killer” T cells and macrophages. CD8+ killer T cells, also known as cytotoxic T cells, lyse target cells directly, while macrophages, a kind of antigen-presenting cell, are also involved in T-cell activation.
Humoral vs cell-mediated immunity: table.
Humoral | Cell Mediated |
It’s a response mediated by antibodies | It’s a T-cell-mediated reaction. |
Extracellular fluids is where it works. | its activity is centred on the location of antigen-presenting tissue. |
Main type of Cells Involved is B cells | Main type of Cells Involved is T cells |
There is a Fast response upon detection | There is a Slow response |
The type of antigen is Extracellular pathogens | The type of antigen is Intracellular pathogens, cancer cells |
Method of removal is Antibody-mediated destruction or neutralization | Method of removal is Cell lysis and programed death |
MHC class II proteins is involved. | MHC class I proteins is involved. |
Conclusion :
The humoral immune response, in which antibodies produced by B cells destroy extracellular bacteria and limit the spread of intracellular illnesses, protects the extracellular spaces.
Cell-mediated immunity is primarily responsible for the removal of virus-infected cells, but it also plays a role in the defence against fungi, protozoa, intracellular bacteria, and cancers. It also plays a significant role in transplant rejection.
