The advantage of the H factor in bacteria. Introduction: The series of 20 proteins naturally found in serum form the complement. The complement pathway is the cascade process that attacks foreign invaders by enhancing the effect of antibodies. The complement system induces pores in the bacterial membrane leading to cytoplasmic leakage. Sometimes the pathogen can take advantage of these controls to avoid being destroyed by the immune system of the human body.

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Chapter 23.6, Problem 1TQ

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The advantage of the H factor in bacteria.

Introduction:

The series of 20 proteins naturally found in serum form the complement. The complement pathway is the cascade process that attacks foreign invaders by enhancing the effect of antibodies. The complement system induces pores in the bacterial membrane leading to cytoplasmic leakage. Sometimes the pathogen can take advantage of these controls to avoid being destroyed by the immune system of the human body.

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Mannose binding lectins (MBL) and ficolins are the two classes of proteins that can initiate the lectin pathway of complement activation. These proteins are selective for activating complement on the surfaces of microbial pathogens rather than host cells because: Their higher-order oligomeric structure can be assembled only after the monomers first bind to pathogen membranes. They only recruit MASP (MBL-associated serine proteases) proteins when bound to pathogen surfaces and not when bound to host cells. They only undergo the conformational change needed to activate MASP proteins when bound to a pathogen and not when bound to a host cell. They only bind to carbohydrate side chains and oligosaccharide modifications found on pathogen surfaces but not on host cell membranes. The activated MASP proteins are rapidly inactivated by hydrolysis when present on the surface of a host cell.

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