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MNS
Question | Answer |
---|---|
Glycophorins A and B carry the MNS antigens, and they may also serve as receptors for | cytokines and pathogens, including the malaria parasite, Plasmodium falciparum. |
Which chromosome contains the MNS antigen gene? | chromosome 4 |
Frequency of MNS antigens (%) | M: 78% Caucasians, 74% Blacks N: 72% Caucasians, 75% Blacks S: 55% Caucasians, 31% Blacks s: 89% Caucasians, 93% Blacks |
Frequency of MNS phenotypes (%) | M+N+S-s+: 22% whites, 33% Blacks M+N+S+s+: 24% Caucasians, 13% Blacks M-N+S-s+: 15% Caucasians, 19% Blacks M+N-S+s+: 14% Caucasians, 7% Blacks M+N-S-s+: 8% Caucasians, 16% Blacks M-N+S+s+: 6% Caucasians, 5% Blacks M+N-S+s: 6% Caucasians, 2% Blacks |
Function of MNS antigens | Glycophorins A and B may serve as receptors for cytokines, bacteria, and viruses, but the lack of the glycophorins does not result in disease, indicating that their function is not physiologically significant |
Individuals who have rare blood types in which either the glycophorin A or B is absent, e.g., phenotypes En(a-) and S-s-U-, have RBCs that are resistant to invasion by these organisms. | Plasmodium |
Are Anti-M and anti-N considered to be a cause of transfusion reactions | Anti-M and anti-N are not considered to be a cause of transfusion reactions, although rare cases of delayed transfusion reactions have occurred as a result of anti-M. Anti-M is fairly common; mostly naturally occurring |
Describe complexity of glycophorins A and B | Glycophorins A and B are single-pass, transmembrane proteins. Glycophorin A contains abundant sialic acid, which contributes to the negative surface charge of the RBC membrane. |