Immatology Assignment

The immune system is made up of several types of cells that work together to fight infections. Lymph cells (called lymphocytes) are the main type of cell in the adaptive immune system. There are 2 types of lymph cells: T cells and B cells. When B cells respond to an infection, they change into plasma cells. The plasma cells are found mainly in the bone marrow—the soft, inner part of some bones. The plasma cells

Innate immunity refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. Adaptive immunity refers to antigen-specific immune response.

They are known as T- Lymphocytes and B-Lymphocytes. B-cells are usually distinguished with humoral immunity because b-cells circulate freely through the lymph system. Whereas T-cells are distinguished by humoral immune response because they act with antigens within other cells. Once these lymphocyte have been produced with the help of bone marrow stromal cells (which are a type of stem cell that is present in red bone marrow) they are released into the blood stream where they travel up to the thymus, and other lymphoid organs. When B-cells, also known as memory cells, leave the bone marrow, they become activated (true b-cells) This process involves the addition of a membrane protein known as immunoglobin M. (IgM) This membrane protein acts a receptor for antigens. Therefore they can said to be the binding site for antibodies. Once an antigen attaches itself to IgM receptor, a signal transduction pathway occurs through tails that descend down into the cells cytoplasm causing them to release antibodies. The second cell type, T-cells, are produced in the bone marrow, through the the same way B-cells are produced. The only difference is they mature in the thymus. This occurs because they undergo genetic recombination of their alpha

Humans such as us alike cannot live in a world without a highly effective defense system that helps us to resist against infections and toxins caused by microorganisms. The immune system is a complex network of consorting cells, tissues and organs that defend the body from pathogens and other harmful substances. This essential complex consists of two subsections : the innate immune system and the adaptive immune system.

They go through negative selection after V(D)J recombination where the self-reacting cells are eliminated. Positive selection is in the periphery and where B cells become mature B-cells. Unlike T-cells, B-cells also go through hypermuation and class switching in the lymph nodes after they are activated. This helps them be more specific for antigens. B-cells either proliferate into memory B-cells or plasma cells that secrete antibodies. Antibodies opsonize, neutralize or fight by complement fixation against the virus. The memory cells are used if an infection of the same virus occurs

The effector cells of the cellular immunity are responses from T-cell-mediated cells. The humoral effect on the immune systems is that the B cells recognize the antigen in the blood or the lymph. Once it recognizes the antigen, it is able to produce antibodies that are specific to the antigen, thus removing the antigen from the body. The B cells also create memory cells that will provide immunity to the antigen in the future. The cellular immunity’s effect on the immune response is the T cells recognize antigens. T cells are not able to bind with the antigens directly, so they require the assistance from MHC-bound peptides. Once the T cell is activated, the T cells produce gene products and create memory cells. T cell activation activates B cells as

The immune system utilizes vaccination as a method of triggering the immune system. Small doses of an antigen, such as either a dead or a weakened live virus, are then given to activate immune system “memory” (activated B cells and sensitized T cells), Memory allows the human body to react quickly and efficiently to future exposures with the pathogen. Through the use of the specific immune system, the immune system will develop a defence against the invading virus.

The killer T cells detect the antigen located on the surface of the infected cells which then releases perforin that attaches to the infected cells. This makes pores within the infected cell and can let ions and water to diffuse inside the cell which therefore causes cell lysis.

The memory T cells can differentiate into Central memory T cells (TCM), effector memory T cells (TEM), or tissue-resident memory T cells (TRM). In addition, these memory T cells produce more IFN-gamma and other cytokines that recruit other effector cells. Also, CD4 T cell help is required for CD8 T-cell memory and involves CD40 and IL-2 signaling. The differentiation of Memory T cells into effector TH1 and CTLs cells can help eliminate this viral infection in the ways that I described in part (a).

It can then activate and rapidly reproduce the B cells, certain proteins that the virus releases allow the infected B cells to survive the germinal centre reaction and form resting memory B cells. Thereafter the virus slows its release of proteins to a rate where it’s still able to avoid any responses the hosts immune system may have.

B cells recognize current or past antigens, ‘mark’ what cells are invaders, and produce antibodies for those antigens. The killer T cells are the cells that expel those antigens from the body. Killer T cells have one objective and that is to be the terminator(imagine Arnold Schwarzenegger saying that) of those viruses and antigens in your body. Helper T cells also regulate immunity.

Adaptive, or acquired, immunity refers to antigen-specific defence mechanisms that take several days to become protective and are designed to react with and remove a specific antigen. This is immunity develops throughout life.

Lymphocytes are a type of white blood cell, which are an important part of the immune system. Lymphocytes can defend the body against infection because they can distinguish the body’s own cells from foreign ones. Once they recognize foreign material in the body, they produce chemicals to destroy that material. Two types of lymphocyte are produced in the bone marrow before birth.

The immune system is comprised of two responses: the adaptive immune response and the innate immune response. The first line of defence against invading organisms is classified as the innate immune response and the second line of defence and protection against re- exposure to the same pathogen is known as the adaptive immune response.

Our immune system is made up of two parts that work together to keep us healthy. The first part is called the innate immune system, it is made up mostly of ‘scavenger’ and ‘killer’ cells that fight off bacterial infections and give the body a general defense against harmful substances. The second part of the immune system is called the adaptive immune system. This part