Last updated on May 30th, 2021Activation of B cells requires two signals. Depending on the nature of the antigen, B-cell activation proceeds by two different routes, one dependent on helper T cells (TH cells), the […]
Last updated on June 11th, 2021Immunity is defined as the resistance offered by the host against microorganisms or any other foreign substance(s). Immunity can be broadly classified into two types: Innate Immunity-present right from the […]
Last updated on June 11th, 2021The initial encounter of a naïve immune-competent lymphocyte with an antigen induces a primary immune response; a later contact of the host with the same antigen will induce a more […]
Last updated on June 11th, 2021The advent of Electron Microscopy in 1932 opens the door to visualizing small subcellular structure and viruses which were beyond the scope of light microscopy which can’t resolve objects separated […]
Last updated on June 11th, 2021Major histocompatibility complex (MHC) is a tightly linked cluster of genes present in every mammalian species. The MHC is referred to as the HLA complex in humans and the H-2 complex […]
Last updated on June 11th, 2021Bacillary dysentery also known as shigellosis is a bacterial disease caused by a group of bacteria called Shigella spp. Other bacterial causes of dysentery are, Vibrio parahaemolyticus, Enteroinvasive E.coli (EIEC), […]
Last updated on June 11th, 2021Taeniasis is the parasitic infection of humans caused by adult tapeworm species; i.e. Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), or Taenia asiatica (Asian tapeworm). T. solium and T. saginata have a worldwide distribution but […]
Last updated on June 11th, 2021Staphylococcus and Micrococcus both are Gram-positive cocci (GPC). Both of these cocci are non-motile, non-sporing, and catalase positive. Both of these organisms are normal flora of the skin and mucous membranes […]
Last updated on June 11th, 2021Neisseria gonorrhoeae and Neisseria meningitides are Gram negative diplococci (kidney bean-shaped) with flattened sides. They are characteristically found inside polymorphonuclear leucocytes. They are non-sporing, non-motile and oxidase positive. They have […]
Last updated on June 11th, 2021All living cells can be classified as either prokaryotic or eukaryotic. Bacteria are prokaryotic, while fungi, protozoa, and other organisms are eukaryotic. Eukaryotic cells contain a nucleus with a nuclear […]
Last updated on June 11th, 2021Staphylococcus and Streptococcus are the two most common pathogenic gram-positive cocci of medical importance. They share some of the important properties. Common characteristics shared by these gram-positive cocci are: Nonmotile, […]
Last updated on June 12th, 2021The cell wall of Gram-negative bacteria is more complex than those of Gram-positive bacteria. Gram-negative bacteria contain an extra layer of cells called outer membrane or lipopolysaccharide (LPS) layer which […]
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