Question

At 2 years of age, John Locke was infected with the MIB virus that had the following serotype: A1, B7, C2. John was later (5 years of age) infected by a variant of he MIB virus that has a A2, B7, C4 serotype. When John was 20 years old he was infected by a virus that had a serotype of A1, B5, C2. Discuss which antigen was important for the response at the 5 year old and 20 year old infection, and what this general phenomenon is called.

I said that A2 and C4 were at the 5 year infecction and B5 at the 20 year infection and that the phenomenon is immunological memory, but I got this question wrong. Can you please expalain in as much detail as possible what the correct answer is? Thank you so much!

Answer 1

• Antigen is a foreign body often a small portion such as a polysaccharide or a protein of a microorganism which holds the capacity to evoke or generate a immunological response i.e production of antibodies and bringing the phagocytic cells into action to eliminate the pathogen from the body.
• There might be more than one antigen on a single microbe such as flagellum and lipopolysaccharides are two different antigens on a single microbe.
• Every time a type of pathogen infects the human body antibodies are produced against all its antigens i.e all the antigens present on that microbe and there are memory cells in the body which store this antigen information for future responses thats why they say if you once get chicken pox you wont get it again because the information regarding its antigen will be stored in the body and even if you get infected by it your body produces a counter attack so fast that it wont give enough time for the pathogen to cause disease condition.
• The question was about the immune response of the body towards the serotype.
• Hence in the above mentioned case when John Locke gets infected for the first time with serotype A1 B7 C2 he gets immunized for these antigens and at five years of age with a different serotype with A2 B7 C4 since there is already a known antigen B7 the memory cells have the machinery ready for attack they induce an immediate immunological response unlike the first when immune cells didnt have any idea about the antigens so body takes a long time to study and get the knowledge of the antigen.
• Again when he got infected at 20yrs age with serotype A1 B5 C2 his body might have immediately launched the immune response because there would be memory cells each for A1 & C2 antigens.