are pathogenic bacteria antigenic
Abstract. Antigenic variation is the means by which a number of highly pathogenic microorganisms, ranging from the electronmicroscopic human viruses to bacteria to fungi and unicellular protozoan parasites, passively evade immune surveillance.ahoon LA and Seifert S (2011) Focussing homologous recombination: pilin antigenic variation in the pathogenic Neisseria. Molecular Microbiology 81(5): 1136–1143. Citti C and Rosengarten R (1997) Mycoplasma genetic variation and its implication for pathogenesis. Wiener Klinische Wochenschrift 109(14–15): 562–568. Antigenic variation is exhibited by a number of highly pathogenic microorganisms including human viruses, bacteria, fungi and unicellular protozoans.Antigenic variation poses challenges to vaccine development against microorganisms causing major public health problems globally.ahoon LA and Seifert S (2011) Focussing homologous recombination: pilin antigenic variation in the pathogenic Neisseria. Molecular Microbiology 81(5): 1136–1143. Citti C and Rosengarten R (1997) Mycoplasma genetic variation and its implication for pathogenesis. Wiener Klinische Wochenschrift 109(14–15): 562–568. Steven.J.Norris@uth.tmc.edu. Comment on Mol Microbiol. 2006 Jun;60(6):1329-43. A common mechanism of immune evasion in pathogenic bacteria and protozoa is antigenic variation, in which genetic or epigenetic changes result in rapid, sequential shifts in a surface-exposed antigen.In this issue of Molecular Microbiology, Dai et al.he vlsE antigenic variation locus of Lyme disease spirochaetes, although similar in sequence to the relapsing fever vlp genes, has evolved a completely different antigenic variation mechanism involving segmental recombination from a contiguous array of vls silent cassettes. Antigenic variation refers to the mechanism by which an infectious agent such as a protozoan, bacterium or virus alters its surface proteins in order to evade a host immune response. It is related to phase variation.ntigenic variation is the expression of various alternative forms of antigen on the cell surface. Whereas phase variation is the phenotypic switch that is usually reversible and is referred to as an ON-OFF switch. Pathogens are any foreign organisms that cause diseases in host plants and animals; e.g. virus and bacteria. Antigen is a molecule located in the cell wall of bacteria or the coating of organisms.Antigen causes our immune system to produce the antibody against it and protect our body from harmful foreign organisms.t causes our immune system to produce the antibody against it. Antibody is used by the immune system to identify and neutralize the foreign particles like bacteria and viruses. Basically, antigens are categorized as self-antigen and non-self-antigen. Many pathogenic bacteria exist in nature as multiple antigenic types or serotypes, meaning that they are variant strains of the same pathogenic species. For example, there are multiple serotypes of Salmonella typhimurium based on differences in cell wall (O) antigens or flagellar (H) antigens.any pathogenic bacteria exist in nature as multiple antigenic types or serotypes, meaning that they are variant strains of the same pathogenic species. For example, there are multiple serotypes of Salmonella typhimurium based on differences in cell wall (O) antigens or flagellar (H) antigens. Many pathogenic bacteria exist in nature as multiple antigenic types or serotypes, meaning that they are variant strains of the same pathogenic species. For example, there are multiple serotypes of Salmonella enterica based on differences in cell wall (O) antigens and/or flagellar (H) antigens.any pathogenic bacteria exist in nature as multiple antigenic types or serotypes, meaning that they are variant strains of the same pathogenic species. For example, there are multiple serotypes of Salmonella enterica based on differences in cell wall (O) antigens and/or flagellar (H) antigens. Pathogens are easily called as infectious agents. We contact pathogens in our daily life. These are microorganisms that cause diseases in host plants and animals; e.g. virus, bacteria, and fungi. Not all microbes are harmful; pathogens refer specifically to the ones that can cause disease in the host.t causes our immune system to produce the antibody against it. Antibody is used by the immune system to identify and neutralize the foreign particles like bacteria and viruses. Basically, antigens are categorized as self-antigen and non-self-antigen. Antigenic variation is employed by a number of different protozoan parasites. Trypanosoma brucei (the model for study of protozoan antigenic variation) and Plasmodium falciparum are some of the most well studied examples of protozoan parasites that exhibit antigenic variation.ntigenic variation is the expression of various alternative forms of antigen on the cell surface. Whereas phase variation is the phenotypic switch that is usually reversible and is referred to as an ON-OFF switch. We review how bacterial, protozoan and fungal pathogens from distant evolutionary lineages have evolved surprisingly similar mechanisms of antigenic variation to avoid eradication by the host immune system and can therefore maintain persistent infections and ensure their transmission to new hosts.echanisms involving DNA recombination. DNA recombination that leads to the movement of non-expressed coding regions into defined genomic expression sites is one of the most common molecular mechanisms used by both bacterial and eukaryotic pathogens to produce antigenic variation (Fig. 4a).
Yes