Neisseria meningitidis Antigens

Neisseria meningitidis, also known as the meningococcus, is a gram-negative, β-proteobacterium. It can survive for only a few hours on inanimate surfaces and exists in encapsulated or unencapsulated forms as an aerobic diplococcus. The human species is the only natural host for the meningococcus. Approximately 10% of the human population carries N. meningitidis asymptomatically in the oropharynx mucosal surface. Transmission occurs through close contact with carriers by inhaling respiratory secretions and saliva. Certain clonal groups of meningococci have evolved the capacity to cause invasive disease. Invasive meningococcal disease (IMD) is a significant global public health concern, resulting in high morbidity and mortality rates. IMD can occur as an endemic disease with sporadic cases or epidemics with outbreaks. Among the 13 serogroups of N. meningitidis, serogroups A, B, C, W-135, and Y are primarily responsible for the majority of IMD cases worldwide.

Fig. 1. Cross-sectional view of the meningococcal cell membrane. (Rouphael NG, et al. 2011).

The subcapsular cell envelope of N. meningitidis includes several layers: an outer membrane (OM), a peptidoglycan layer, and an inner membrane. The OM consists of an external layer primarily composed of lipooligosaccharide (LOS) and proteins. The inner membrane contains phospholipids, including phosphatidylethanolamine (PE), phosphatidylglycerol (PG), cardiolipin (CL), and phosphatidate (PA). The primary virulence factor of N. meningitidis is the polysaccharide capsule which helps the bacterium evade the host's immune system by resisting phagocytosis, which is the process by which immune cells engulf and destroy pathogens. Apart from the capsule, N. meningitidis produces other virulence factors such as pili, porins (PorA and B), and adhesion molecules (Opa and Opc). These factors aid in the attachment to host cells and colonization of the mucosal surfaces in the upper respiratory tract. In addition, its endotoxin LOS can induce host inflammatory response.

With years of production experiences in the field of antigens and antibodies, Creative Diagnostics now can provide various Neisseria meningitidis antigens for multiple applications for both academic and industry researches, including various serogroups of Neisseria meningitidis capsule polysaccharide (CPS) and their CRM197-conjugates.