Streptococcus pneumoniae is a Gram-positive and fast-growing bacteria which inhabit upper respiratory tract in humans. Moreover, it is an aerotolerant anaerobe and usually causes respiratory diseases including pneumonia, otitis media, meningitis, peritonitis, paranasal sinusitis, septic arthritis, and osteomyelitis (Todar, 2003). According to Tettelin et al., more than 3 million of children die from meningitis or pneumonia worldwide (2001). S.pneumoniae has an enzyme known as autolysin that is responsible for disintegration and disruption of epithelial cells. Furthermore, S.pneumoniae has many essential virulence factors like capsule which is made up of polysaccharides that avoids complement C3b opsonization of cells by phagocytes. Many vaccines contain different capsular antigens which were isolated from various strains (Todar, 2003). There are plenty of S.pneumoniae strains that developed resistance to most popular antibiotics like macrolides, fluoroquinolones, and penicillin since 1990 (Tettelin et al., 2001). Antibiotic resistance was developed by the gene mutation and selection processes that, as a consequence, lead to the formation of penicillin-binding proteins, etc. (Todar, 2003).
People infected with Human Immunodeficiency Virus (HIV) have a sequential destruction of CD4 T cells which always lead to a weakening of the immune system. Despite the reduction of CD4 T cells, the macrophages and dendritic cells are also affected by HIV. Moreover, HIV causes a dysfunctionality in B cells, CD8 T cells, and innate immune system cells (Shipley, 2013). For instance, the reduction of perforin production and IFN-γ secretion in CD8 T cells cannot help effector T cells to destruct virus-infected cells (Kuerten et al., 2008). The reduction of costimulatory activity, chemotaxis, and ability to be activated by T helper cells are caused by HIV in B cells. Another examples of dysfunctionality in innate immune system are the loss of phagocytic ability in neutrophils and macrophages, decreased number of dendritic cells (DCs), less production of IFN-γ, and disruption of the synthesis of Th1 cytokines (Shipley, 2013). All of these negative consequences impair the immune system by the cause of Human Immunodeficiency Virus.
Our task was to design a vaccine against opportunistic infection, which can be used in HIV patients. The designed vaccine should fight the pathogen in that way that could alter the immune response in people having HIV. In our case, the vaccine should destruct Streptococcus pnemoniae bacteria avoiding obstacles which caused by Human Immunodeficiency Virus. In fact, the majority of current vaccines contain pneumococcal capsular polysaccharides. Although most of them reduced pneumococcal diseases, some limitations have been eventually occurred due to horizontal gene transfer, genetic mutations and variations which change the composition of capsule in bacteria (Denoel et al., 2011).
The designed vaccine will be a conjugated pneumococcal...