The Expression, Regulation And Function Of Superantigens Of Streptococcus And Staphylococcus

Signaling proteins that alert the immune system an infection is present and that sometimes directly fight pathogens are the:

The immune system is made up of trillions of specialised cells (white blood cells) that detect and destroy pathogens or their toxins. Some white blood cells, which are

“Bacterial illness is a result of complex interactions between bacteria and the host. During evolution, humans developed many ways to protect themselves against bacterial pathogens. On the other hand, bacteria have developed strategies to evade, subvert or circumvent these defenses” (Sousa, 2003) “One of the most important characteristics of bacterial pathogenicity is the various strategies developed by prokaryotic organisms to use host molecules for their own benefit” (Sousa, 2003). “To accomplish this, bacteria have evolved elaborate control mechanisms to turn genes on and off, varying the transcriptional activator or

this occurs in a series of steps, the first of which is incorporation of unidentified antigens by APCs in the epidermis and dermis. This process involves binding of the antigens to the MHC on the APC surface and the APC migrates to the lymph nodes. There, the APC binds reversibly and briefly with naïve or resting T cells through interactions between surface molecules located on both cells. Next, the MHC presents the antigen to a T lymphocyte receptor to begin activation of the T lymphocyte. The second signal for T lymphocyte activation is a non-antigen/ cell-cell interaction known as costimulation. If costimulation does not occur, the T lymphocyte will either undergo apoptosis or become unresponsive. Costimulation involves pairing of receptor with ligand on the T cell; these pairs include (LFA)-3 interacting with CD2, B7 interacting with CD28, and ICAM-1 interacting with LFA-1 (Lebwohl, 2003).

Within the immune system, the thymus receives immature T cells from the bone marrow and turns them to mature T cells so that they can detect foreign substances. Antigens from epithelial cells are presented to the immature T cells. The T cells that recognize the antigens of the foreign cells continue to be tested and shown native cells from the body. If the T cells bind to the native cell, they are labeled autoimmune and destroyed, but those that

Abstract When performing this lab, we demonstrated that Ecoli bacteria could have its DNA changed through a process called transformation. We inserted a plasmid for pGLO into the DNA of bacteria through a method know as heat shock. The pGLO was inserted in order to alter the phenotipic characteristics of that bacteria, and manipulate it's genetic code, so that it would glow when exposed to an ultra violet light.

The TH1 response is cell mediated and promotes inflammation while the TH2 response is an antibody response and anti-inflammatory. When excessive, the TH1 response can cause extensive tissue damage. TH1 responses are characterized by IFN-gamma production. IFN-gamma produces macrophage activity and causes B cells to create a coating of Abs. This creates a cell-mediated response. This is effective against invaders that are inside of the host cells. In a cell-mediated response, the APC phagocytizes the invader via macrophage, monocyte, or dendritic cell. Next, the antigen enters the lymphatic system via lymph node. The APC presents the antigen to T cells where the T cells recognize the antigen and cytokines are secreted to search and destroy

Both, Dr. Bassler and Dr. Dalino, explain how bacteria communicate and work together through quorum sensing. As Basler explained in her TED talk, bacterial cells make single producing proteins that attract other surrounding bacteria. They are able to receive these signals trough the signal receptor protein; this protein allows the bacteria to recognize when the cell density is high or low. If the cell density is high enough to perform the desired action, the group behavior turns on and they are able to work effectively as a way to reach their purpose. By working together, they are able to control pathogenicity and virulence; they continue to grow in their biofilms until they know they will be successful. Additionally, these single producing proteins are specific for intra-species communication meaning that the protein

And then even if the immune system is like, hey! Code Red! We’ve got cancer over here! It often can’t muster a strong enough response to kill those multiplying cells without help.

This is one method through which the body regulates the immune system, to avoid an overreaction. Many cancer cells make PD-L1, which inhibits T cells from

Escherichia coli (E.coli) is a gram-negative bacterium meaning that it is bacteria that does not retain crystal violet after the decolorization step. However alcohol used in this stage degrades the outer membrane making the cell wall more porous and incapable of retaining the crystal violet strain. Compared to staphylococcus epidermidis their peptidoglycan layer is much thinner and is surrounded between an inner cell membrane and a bacterial outer membrane. It is a facultative anaerobe, which is an organism that makes ATP by aerobic respiration if oxygen is present. However it is capable of switching to anaerobic respiration is oxygen is not present. E.coli is a rod shape bacterium of the genus Escherichia. This type of bacteria is commonly found in the lower intestine of endotherms.

What is DNA? - DNA or deoxyribonucleic acid according to Genetic Home reference is the hereditary in humans and all other organisms. The website said that nearly every cell in a person’s body has the same DNA. They say that most DNA is located in the cell’s nucleus, but smaller amounts of DNA can be found in the mitochondria. They said that DNA bases pair up with each other. “A” or adenine goes with “T” or Thymine and “G” or guanine goes with “C” or cytosine. These pairs are called base pairs. According to genetics home reference an important property of DNA is that it can replicate, or make copies of itself. Your Genome said “DNA is a long molecule that contains our unique genetic code. Like a recipe book it holds instructions for making all the protein in our bodies.” They

They have rapid effector function and produce large amounts of IFN-, IL-4 and IL-5 within hours of antigenic stimulation (Lanzavecchia and Sallusto, 2000).

Quorum sensing isa form of cell-to-cell communication that bacteria use to coordinate the expression of genes involved in behaviours such as flagellar movement9,10 virulence factor production,11,12 and

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.