That person looks sick... hopefully he does not spread it to me
That person made me sick! My eyes are red and itchy I have a runny nose, a fever and pale skin.
You have measles. Your 3rd line of defence and immune system will make you feel better
When measles invades your body, it attempts to break through the first line of defence, which acts as a barrier to prevent infectious diseases. The first line of defence has physical and chemical barriers. Your first line of defence includes skin, tears, saliva, mucus, stomach acids, cilia and urine flow. The first and second line of defence act as non-specific defence mechanisms, responding to every infection the same way.
If an infectious disease like measles was to invade your body, the third line of defence will target that specific pathogen that has invaded the body. The third line of defence is a specific defence mechanism. When measles invades your body, you will feel symptoms like cough, runny nose, inflamed eyes, sore throat, fever and a red, blotchy skin rash for the first few days, because the third line of defence needs to recognise and identify the pathogen that is invading. The cells that identify specific pathogens are called B-cells(Lymphocyte).
IMMUNE SYSTEM MEMORY CELLS
As the B-cells locate the pathogen in the blood, the B-cells carry proteins called antibodies which bind to markers on the pathogens surface, called antigens. Every single pathogen known to the body has different markers, meaning every time a foreign pathogen invades the body new antibodies are formed.
My immune system cleared of the virus! Am I now immune to measles?
Your memory B-Cells remember the antibodies used in the first encounter so yes
Once the measles pathogen markers are identified and antibodies are formed, the B-cells clones itself to produce millions of antibodies into the blood stream to kill the pathogen. The antibodies that match the antigen’s markers are what neutralise measles from your body.
While the B-cells are fighting off the pathogen, memory b-cells are formed. These memory b-cells remember the antibodies which were formed so in case the antigen invaded the body again the antibodies are ready. The memory B-cells remain in the blood stream and stay therefor your whole life span. Memory B-cells are what allow your body to build immunity against pathogens.
The immune system’s memory b-cells remember the antibodies formed to fight measles, so if the body was exposed to measles again, symptoms will not persist as strong because immunity from the first exposure reduces them. That is how the human immune system works when measles invades the body!