Which neisserial virulence factor is known for high-frequency antigenic variation?

Pilin is a critical virulence factor for Neisseria species, particularly in how it contributes to the bacteria's ability to evade the host immune response. High-frequency antigenic variation refers to the ability of specific surface proteins to change their structure and, therefore, their antigenic properties frequently. This dynamic allows the pathogen to escape detection and destruction by the host's immune system.

In Neisseria, pilin is particularly known for undergoing significant antigenic variation. This occurs through processes like gene conversion and shuffling of pilin genes, allowing the bacteria to produce different forms of pilin on its surface over time. As a result, even if the immune system mounts an attack against a previous form of the pilin, the evolving structure may not be recognized, enabling the bacteria to persist and propagate within the host.

Other factors, such as lipooligosaccharide, while important in eliciting immune responses, do not exhibit the same level of variation as pilin. Capsules can provide a physical barrier to phagocytosis, and opacity proteins may contribute to adhesion and invasion but are not as renowned for variable expression as pilin. Understanding the role of pilin and its ability to change is crucial for comprehending how Neisseria species can