This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Virulence factors for meningococci ? 
Select and explain. 
A. Capsule, B. Pili, C. Endotoxin, D. All
D: All
Answer: D: All 
Explanation: Ans. is 'a' i.e., Capsule; 'b' i.e., Pili & 'c' i.e., Endotoxin The capsular polysaccharide - It is a major virulence factors - It has antiphagocytic and antibactericidal propeies. - Based on capsular polysaccharide, meningococci have been divided into serogroups. Outer membrane proteins - Pili - Facilitate adhesions - Porins Por A and Por B - Opc - is involved in cell attachment and is a target for bactericidal antibodies. - IgA1 protease - protects from the action of mucosal IgA. - Systems for acquisition of iron - carrying molecules like transferrin and lactoferrin. Lipooligosaccharide (Endotoxin) - Mediates the induction of inflammatory cytokines. - The morbidity and moality of meningococcal bacteremia and meningitis have been directly correlated with the amount of circulating meningococcal endotoxin.