Salmonella Enterica Mechanisms of Overcoming Host Acquired Immune System: A Review

Salmonella spp. are pathogenic Gram-negative, rod-shaped, motile bacteria belonging to the family Entero bacteriaceae. Salmonella enterica serovar Typhi (S. typhi) causes typhoid fever in humans, with an annual global burden of about 16 million cases, leading to 600 000 deaths. Following infections by Salmonella, the innate immune cells like macrophages, dendritic cells (DCs) and neutrophils engulf and destroy microorganisms while adaptive immunity is mediated via the generation of antigen-specific B and T lymphocytes, through a process of gene rearrangement resulting in the production and development of specific antibodies and killer T cell, respectively. However, Salmonella has developed molecular mechanisms to prevent the presentation of bacterial antigens that prime naive T cells and therefore avoid the initiation of the acquired immunity. Such mechanisms include; modulating phagocytosis by dendritic cells, avoiding lysosomal degradation and preventing antigen presentation to T cells. The paper reviews the concept of acquired immune and some strategies used by Salmonella to deal with the different levels of acquired immunity of the host.

Keywords: Acquired immunity, Immune system, Lymphocyte, Salmonella.