Individuals with a genetic polymorphism in the Fc$\gamma$ receptor, Fc$\gamma$RIIa (CD32), have an increased susceptibility to bacterial meningitis (inflammation of the membranes (meninges) surrounding the brain and spinal cord) caused by the encapsulated bacterium, Neisseria meningitidis. This polymorphism reduces the efficiency with which the phagocytes expressing Fc$\gamma$RIIa bind to the constant region of this receptor's target antibody. The reason this Fc$\gamma$RIIa-dependent response it the major form of protection against Neisseria meningitidis is because:

Question

Quizplus · Accepted Answer

IgG antibodies are able to diffuse into tissues and bind to the capsule of encapsulated bacteria, such as Neisseria meningitidis. This binding allows phagocytes expressing FcRIIa to recognize and phagocytose the bacteria, providing protection against infection. As the FcRIIa-dependent response is the major form of this protection, a genetic polymorphism that reduces the efficiency of this binding can result in an increased susceptibility to bacterial meningitis.

Individuals with a Genetic Polymorphism in the Fc γ\gammaγ Receptor, Fc γ\gammaγ

Individuals with a Genetic Polymorphism in the Fc $\gamma$ Receptor, Fc $\gamma$