Which is an automatic response provided by our skin when subjected to an infectious agent?

The automatic response to any infectious agent by our body is inflammation which is an automatic response by the tissues of body to any external stimulus like pathogens or any other infectious agent like virus, bacteria, insects etc.  

The antigen stimulates the immune response by activation of the lymphocytes either to produce the antibody or to attack directly. The receptors of the lymphocytes for the molecules on the antigen's surface stimulates lymphocytes and starts the immune response .

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