Adaptive immunity mechanisms: Nursing pathophysiology

Adaptive immunity is part of the immune system that can provide longlasting immunity. It's sometimes called acquired immunity because it's not present at birth and develops over time.

Now, adaptive immunity has certain characteristics that sets it apart from the innate or the general immune defense, an individual is born with, including that it's inducible specific systemic, long lived and it has an immunologic memory.

So, inducible and specific mean that adaptive immunity is not always actively present, but instead it's explicitly developed against a particular antigen which are molecules found on the surfaces of microorganisms and abnormal cells that trigger an immune response.

Next, systemic means that immune cells can mount an attack throughout the body. Finally, adaptive immunity is long lived and has an immunologic memory, meaning certain immune cells called memory cells linger in the body.

So the next time the body is exposed to the same pathogen, it can mount a faster and stronger response. The main components of adaptive immunity include lymphocytes or white blood cells and antibodies.

The most prominent lymphocytes in the adaptive immune system are T lymphocytes or T cells and B lymphocytes or B cells. These cells interact with other components of the immune system such as dendritic cells, natural killer cells and macrophages.

Antibodies also called immunoglobulins are glycoproteins that assist in fighting infections. Now, the main mechanisms of adaptive immunity are induction, cell mediated immunity, humoral immunity.

And immunologic memory induction involves the activation of the adaptive immune system in response to an antigen and the process differs between B and T cells.

The first step in T cell induction is when certain cells most often macrophages and dendritic cells serve as antigen presenting cells or AP CS because they identify process and present antigens to at cell, which is called a naive T cell at this stage.

However, the T cell will only recognize the antigen if it's presented on a molecule called a major histocompatibility complex or MHC, which are proteins found on the surface of most human cells.

Now, there are two main types of MHC proteins that work with T cells. MHC, one proteins present to T cells that express CD eight surface receptors.

Once the antigen is presented, CD, eight T cells are activated and differentiate into cytotoxic T cells or TC cells which kill infected or other abnormal cells like cancer cells.

MHC two proteins present to T cells that express CD four surface receptors. After presentation, these cells differentiate into helper T cells called T cells which primarily support other immune cells like macrophages, B cells and cytotoxic T cells.

These helper T cells include th one cells that help macrophages become better phagocytes and help cytotoxic T cells to proliferate th two cells that help B cells differentiate th 17 cells that promote inflammation and help maintain the epithelial cell barrier and regulatory T cells or Tregg cells that inhibit the immune response.

So it will end when the infection has been controlled. On the other hand, B cells can become activated by binding to an antigen directly or it can become activated with the assistance of a th cell.

Once activated B cells differentiate into plasma cells which produce antibodies against the specific antigen. Now, the primary player in cell mediated immunity are cytotoxic T cells and they have a couple of different ways to kill target cells.

First, they produce cytotoxic Granules like perforin and enzymes. Once the cytotoxic T cell binds to the target cell, the perforans punch holes in the cell's membrane and release the grand enzymes into the target cell triggering apoptosis or cell death.

Cytotoxic T cells also have a death ligand called a CD 95 ligand, also called a fast ligand that can bind to complement proteins on the surface of target cells triggering apoptosis.

In addition to their role in innate immunity, other cells involved in adaptive cell mediated immunity include natural killer cells and macrophages.

Natural killer cells can identify and then kill abnormal cells using cytotoxic Granules or death ligans, macrophages. In addition to acting as an antigen presenting cell use phagocytosis and the release of proinflammatory cytokines to kill abnormal cells, humoral immunity fights infection with antibodies which are produced by B cells that have transformed into plasma cells.

These antibodies are classified by their chemical structure and function and include five types, IgG, IG M IG A I GE and I GD.

Some antibodies are expressed on the B cell surface and directly bind to an antigen. While other antibodies are secreted by the B cell, which are also called soluble antibodies that circulate freely in body fluids like blood and lymph.

Lastly, immunologic memory develops during T and B cell activation. When some of these cells differentiate into memory T cells and memory B cells, these cells are long lived, remain in the lymphatic system and remember how to recognize specific antigens.

So they can rapidly respond during a subsequent exposure. All right, as a quick recap adaptive immunity is part of the immune system that can provide longlasting immunity following exposure to an antigen.

It's inducible specific systemic long lived and has a memory. Adaptive immunity involves induction where an antigen activates immune cells, cell mediated immunity that creates cytotoxic T cells and T cells humoral immunity which creates antibodies and immunologic memory that uses memory B and T cells to help remember the pathogen upon subsequent exposures.