Abstract

Bacterial infections have a significant impact on animal and human immunity. Bacteria must encounter with host in order to produce infection and inflammation. Pathogenic microorganisms can be transmitted through a variety of mechanisms. Bacterial infections are induced by two main processes fist bacteria cause inflammation, which leads to tissue destruction at the infection site. Second, bacteria produce toxins. Collectins, pentraxins, and ficolins are soluble PRRs. Complement proteins are required for the quick clearance of invading bacteria by innate defense mechanisms such as inflammation, opsonization, and bacteriolysis. Inflammation is triggered when bacteria or their products interact with molecules and cells of the innate immune system. Natural killer cells are a diverse population of innate immune cells capable of killing cells with low expression of MHC class I molecules. Bacterial super antigens are protein toxins that have the ability to cause significant immune system activation. Cell-Mediated Immunity effector mechanisms are mediated by cells rather than antibodies in cell-mediated immunity.