Bacterial Evasion Essay

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Humans and bacteria have a unique relationship, which has both positive and negative outcomes on human beings. In fact, the human body’s surfaces are inhabited by numerous bacteria, known as normal flora (Hornef et al., 2002). These normal flora may act as commensals or be mutualistic, which means that they are either harmless or beneficial microorganisms (Cogen et al., 2008). However, serious invasive diseases, such as meningitis and septicemia are caused by several pathogenic bacteria (Hornef et al., 2002). The occurrence of such diseases requires unique strategies, which assist bacteria to survive inside the host and evade their immune response (Akira et al., 2006). Several pathogenic bacteria have developed efficient capabilities to counteract and circumvent innate immune defenses, as well as adaptive immune defenses (Hornef et al., 2002). This paper will discuss several bacterial evasion mechanisms for innate immunity and the consequences of these for the adaptive …show more content…
The following is a brief review for some evasion mechanisms of adaptive immunity. T cells and B cells are the main components of the adaptive immunity. Besides their abilities to produce a diversity of antibodies against pathogens, they develop memory cells that can remember pathogens antigens (Medzhitov, 2007). Some pathogenic bacteria intervene with T and B cells receptors in order to avoid these cells (Hornef et al., 2002). Yersinia pseudotuberculosis is a good illustration of this mechanism. Yersinia outer membrane protein H (YopH) produces tyrosine phosphatase protein, which suppresses interleukin 2 (IL-2) synthesis by the T cell. Moreover, this protein inhibits the activation of T cell antigen- specific receptors. In addition, the B cell shows an incapacity for the up-regulation of the co-stimulatory molecules expression of CD86, in interaction with pathogen stimulation (Yao et al.,

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