S. Pneumoniae is an abbreviation of streptococcus pneumonia, is a normal inhabitant in the human upper respiratory tract, which can lead to pneumonia, a disease of the lung, and is the major cause of invasive bacterial disease in children and the elderly. S. Pneumoniae cells are gram-positive coccus with lancet shap. They are usually seen as pairs of cocci, or diplococci, but they may also present singly and in short chains. When S. Pneumoniaes are cultured on blood agar, they reveal alpha hemolytic. These bacteria are nonmotile organisms and do not form spores. Like other streptococci, S. Pneumoniae lacks catalase and is able to ferment glucose to lactic acid. Unlike other streptococci, they do not display an M protein, but can hydrolyze inulin. FcαRI (Fc fragment of IgA receptor), also referred to FcalphaRI or CD89, is the most prominent and only human immunoglobulin A (IgA) Fc receptor that binds the heavy-chain constant region of IgA via two extracellular binding sites. This receptor is a transmembrane glycoprotein mapping at the chromosome 19q13.42 and belongs to the immunoglobulin (Ig) gene superfamily. FcαRI is expressed on the surface of blood myeloid cells, such as monocyte/macrophages, neutrophils, eosinophils, dendritic cells, and Kupffer cells, in which it mediates immunologic responses to pathogens. IgA plays an important role in immune protection. It interacts with IgA-opsonized targets and initiates a number of immunologic defense processes, for instance, phagocytosis, stimulation of the release of inflammatory mediators, and antibody-dependent cell-mediated cytotoxicity.